Zostera marina, a monocotyledonous angiosperm, is one of the most important seagrass species. To inves- tigate the salt-tolerance mechanism and discover salt-tolerant genes in Z. marina, a cDNA library was con- struct...Zostera marina, a monocotyledonous angiosperm, is one of the most important seagrass species. To inves- tigate the salt-tolerance mechanism and discover salt-tolerant genes in Z. marina, a cDNA library was con- structed. Single-pass sequencing of the 5' ends of 4 081 clones yielded 4 002 high quality expressed sequence tags (ESTs), which were assembled into 241 contigs and 1 673 singletons, representing 1 914 unigenes. The average length of the ESTs was 582 bp, with sizes ranging from 100-1 500 bp. Basic Local Alignment Search Tool (BLASTX) analysis revealed that 1 664 unigenes had significant homology to known genes in the Na- tional Center for Biotechnology Information (NCBI) non-redundant (nr) database (E-value≤5-10). Among them, the two most abundant genes encoded metallothionein (157 ESTs) and chlorophyll a/b-binding pro- tein (38 ESTs), accounting for 7.1% and 1.7% of the total ESTs, respectively. Using Kyoto Encyclopedia of Genes and Genomes (KEGG), 1 462 unigenes were assigned to 1 161 pathways (E-value≤5-10). A total of 938 unigenes were assigned Gene Ontology (GO) terms based on the GO hierarchy analysis, and InterProScan searches recognized 1 003 InterPro families. Three genes for metallothionein in Z. marina that belonged to Class II was identified. Results of this study will improve understanding of the molecular mechanisms of saline tolerance in Z. marina.展开更多
Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Construction of a full-length cDNA library is an effective way to understand the expression of functional genes in muscle ...Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Construction of a full-length cDNA library is an effective way to understand the expression of functional genes in muscle tissues. In addition, novel genes for further research could be identified in the library. In this study, we constructed a full-length cDNA library from porcine muscle tissue. The estimated average size of the cDNA inserts was 1 076 bp, and the cDNA fullness ratio was 86.2%. A total of 1 058 unique sequences with 342 contigs (32.3%) and 716 singleton (67.7%) expressed sequence tags (EST) were obtained by clustering and assembling. Meanwhile, 826 (78.1%) ESTs were categorized as known genes, and 232 (21.9%) ESTs were categorized as unknown genes. 65 novel porcine genes that exhibit no identity in the TIGR gene index of Sus scrofa and 124 full-length sequences with unknown functions were deposited in the dbEST division of GenBank (accession numbers: EU650784-EU650788, GE843306, GH228978-GH229100). The abundantly expressed genes in porcine muscle tissue were related to muscle fiber development, energy metabolism and protein synthesis. Gene ontology analysis showed that sequences expressed in porcine muscle tissue contained a high percentage of binding activity, catalytic activity, structural molecule activity and motor activity, which involved mainly in metabolic, cellular and developmental process, distributed mainly in intracellular region. The sequence data generated in this study would provide valuable information for identifying porcine genes expressed in muscle tissue and help to advance the study on the structure and function of genes in pigs.展开更多
Vitis amurensis is a valuable resource for wine production. Ripening of the grape berry is the key phase which determines the com- position of wine. To better understand the gene expression that manifest in V. amurens...Vitis amurensis is a valuable resource for wine production. Ripening of the grape berry is the key phase which determines the com- position of wine. To better understand the gene expression that manifest in V. amurensis berry skins during the ripening, cDNA library of V. amurensis berry skins was constructed. A total of 935 high quality ex- pressed sequence tags (ESTs) were obtained from the library. These ESTs represent 636 unigenes, including 108 contigs and 528 singletons. The EST analysis was performed and genes were assigned to functional categories according to their primary BLAST match. Of these 25.35% were involved with metabolism, 6.27% with cell rescue and defense, 6.84% energy, 11.68% protein synthesis, 18.8% protein activity regula- tion, 11.11% cell structure, 7.98% transport, 6.27% transcription and the remaining 5.7% were signal transduction. The generated ESTs were characterized by the gene ontology analysis and were categorized ac- cording to its cellular component, molecular function and biological process. In the cDNA library, some genes are relevant to the biosynthesis of anthocyanins, while some genes are related to grape berry maturation.展开更多
In order to study the expression of function gene and its effect on metabolic control and other physiological function in liver, 438 expressed sequence tags (ESTs) were determined, which were from a cD-NA library of p...In order to study the expression of function gene and its effect on metabolic control and other physiological function in liver, 438 expressed sequence tags (ESTs) were determined, which were from a cD-NA library of porcine liver tissue. The results showed that the nucleotide sequences of 186 ESTs have already presented in GenBank database, and 37 ESTs could be found the homology with human and other species, while the others were not identified. 45 full length insertion of the clones randomly isolated from cDNA library were also completely sequenced with different size, and the results showed that 19 of them were function-known genes, 11 had no open reading frame ( ORF )at all and 15 had ORF but the function were not elucidated yet.展开更多
In order to detect the molecular mechanism of heterosis in pigs, the mRNA differential display technique was performedto investigate the differences of gene expression in the backfat tissue from Meishan, Large White a...In order to detect the molecular mechanism of heterosis in pigs, the mRNA differential display technique was performedto investigate the differences of gene expression in the backfat tissue from Meishan, Large White and MeishanLargeWhite cross pigs. Nine 3'-end anchored primers in combination with ten 5'-end arbitrary primers were used to perform thedifferential display PCR and nearly 3 000 reproducible bands were examined. Fifteen expressed sequence tags that weredifferentially expressed were isolated and then identified through semi-quantitative RT-PCR. BLAST analysis revealedthat the fifteen expressed sequence tags (ESTs) were not homologous to any of the known porcine genes or ESTs. Thesenovel ESTs were then submitted to GenBank.展开更多
Gymnadenia conopsea,an alpine Orchidaceae plant,was one of the widely used Tibetan traditional medicines.In this study,we sequenced total 105 expressed sequence tags (ESTs) from a full-length cDNA expression library c...Gymnadenia conopsea,an alpine Orchidaceae plant,was one of the widely used Tibetan traditional medicines.In this study,we sequenced total 105 expressed sequence tags (ESTs) from a full-length cDNA expression library constructed by the Oligo-capping technique.The further bioinformatic analyses suggested that the 65 represented unique sequences showed high homology to previously identified genes in other plants:30 sequences matched to other uncharacterized expressed sequence tags (ESTs),and 10 sequences showed no good matches to available sequences in DNA databases.Gene ontology annotation by InterProScan indicated that many of these cDNAs (7 percent) have no known molecular functions and may be unique to G.conopsea.Fifty-five ESTs with matched proteins were involved in a series of diverse functions,in which molecular function such as 'binding' (42.9 percent) and 'catalytic activity' (25.0 percent) were the most frequent functions of the cDNAs.This cDNA library provided a critical basis for further investigation of functional genes expression under cold stress in this alpine species.In addition,13 ESTs-based polymerase chain reaction (PCR) primers were designed and can also be used for genotypic identification and for the genetic diversity analysis of G.conopsea and its closely related species.展开更多
In this study,64 498 ESTs of Melampsoraspp.was assembled into 1 998 contigs,and 604SSR loci were detected on these contigs,with 736.6 bp containing one SSR on average.Among these SSRs,trinucleotide repeats were the mo...In this study,64 498 ESTs of Melampsoraspp.was assembled into 1 998 contigs,and 604SSR loci were detected on these contigs,with 736.6 bp containing one SSR on average.Among these SSRs,trinucleotide repeats were the most abundant repeats(44.70%).As for the composition of microsatellites, AC and AT repeats were the richest motif in dinucleotide repeats,and AGT and AAG repeats were the most frequent motifs in trinucleotide repeats,whereas(AAAN) n and(AAAAN) n repeats were dominant in tetranucleotide and pentanucleotide repeats,respectively.All the dominant repeat motifs of different types of SSRs were rich in A and T.In EST sequences of Melampsoraspp.genome,microsatellites longer than 20 bp accounted for about 15.07%.It was noticeable that microsatellites were highly rich in the expressed sequences of Melampsoraspp.genome,which implied that SSRs played a significant role in triggering the gene mutation in Melampsoraspp.genome.A total of 455 SSR primers were designed according to the detected microsatellites using Primer 5.0 and Oligo 6. 0,and 30 primer pairs were randomly selected for amplification test.Among these primer pairs,27 primer pairs succeed in amplification,with a successful rate of 90%.Eight primer pairs generated polymorphic fingerprints in Melampsoraspp.collected from different poplar genotypes,accounting for 26.7% of the total primer pairs.The EST-SSR markers developed fromMelampsoraspp.EST sequences provided important marker resources for studying Melampsoraspp.from the aspects of pathogen identification and survey of genetic variation.展开更多
We assembled a total of 297,239 Gossypium hirsutum (Gh, a tetraploid cotton, AADD) expressed sequence tag (EST) sequences that were available in the National Center for Biotechnology Information database, with ref...We assembled a total of 297,239 Gossypium hirsutum (Gh, a tetraploid cotton, AADD) expressed sequence tag (EST) sequences that were available in the National Center for Biotechnology Information database, with reference to the recently published G. raimondii (Gr, a diploid cotton, DD) genome, and obtained 49,125 UniGenes. The average lengths of the U niGenes were increased from 804 and 791 bp in two previous EST assemblies to 1,019 bp in the current analysis. The number of putative cotton UniGenes with lengths of 3 kb or more increased from 25 or 34 to 1,223. As a result, thousands of originally independent G. hirsutum ESTs were aligned to produce large contigs encoding transcripts with very long open reading frames, indicating that the G. raimondii genome sequence provided remarkable advantages to assemble the tetraploid cotton transcriptome. Significant different distribution patterns within several GO terms, including transcription factor activity, were observed between D- and A-derived assemblies. Tran- scriptome analysis showed that, in a tetraploid cotton cell, 29,547 UniGenes were possibly derived from the D subgenome while another 19,578 may come from the A subgenome. Finally, some of the in silico data were confirmed by reverse transcription polymerase chain reaction experiments to show the changes in transcript levels for several gene families known to play key role in cotton fiber development. We believe that our work provides a useful platform for functional and evolutionary genomic studies in cotton.展开更多
Low genetic diversity makes peanut (Arachis hypogaea L.) very vulnerable to plant pathogens, causing severe yield loss and reduced seed quality. Several hundred partial genomic DNA sequences as nucleotide-binding-si...Low genetic diversity makes peanut (Arachis hypogaea L.) very vulnerable to plant pathogens, causing severe yield loss and reduced seed quality. Several hundred partial genomic DNA sequences as nucleotide-binding-site leucine-rich repeat (NBS-LRR) resistance genes (R) have been identified, but a small portion with expressed transcripts has been found. We aimed to identify resistance gene analogs (RGAs) from peanut expressed sequence tags (ESTs) and to develop polymorphic markers. The protein sequences of 54 known R genes were used to identify homologs from peanut ESTs from public databases. A total of 1,053 ESTs corresponding to six different classes of known R genes were recovered, and assembled 156 contigs and 229 singletons as peanut-expressed RGAs. There were 69 that encoded for NBS-LRR proteins, 191 that encoded for protein kinases, 82 that encoded for LRR-PK/transmembrane proteins, 28 that encoded for Toxin reductases, 11 that encoded for LRR-domain containing proteins and four that encoded for TM-domain containing proteins. Twenty-eight simple sequence repeats (SSRs) were identified from 25 peanut expressed RGAs. One SSR polymorphic marker (RGA121) was identified. Two polymerase chain reaction-based markers (Ahsw-1 and Ahsw-2) developed from RGA013 were homologous to the Tomato Spotted Wilt Virus (TSWV) resistance gene. All three markers were mapped on the same linkage group AhIV. These expressed RGAs are the source for RGA-tagged marker development and identification of peanut resistance genes.展开更多
The cotton mealybug, Phenacoccus solenopsis Tinsley, is a serious and invasive pest. At present, genetic resources for studying P. solenopsis are limited, and this negatively affects genetic research on the organism a...The cotton mealybug, Phenacoccus solenopsis Tinsley, is a serious and invasive pest. At present, genetic resources for studying P. solenopsis are limited, and this negatively affects genetic research on the organism and, consequently, translational work to improve management of this pest. In the present study, expressed sequence tags (ESTs) were analyzed from a normalized complementary DNA library of/?. solenopsis. In addition, EST-derived microsatellite loci (also known as simple sequence repeats or SSRs) were isolated and characterized. A total of 1107 high-quality ESTs were acquired from the library. Clustering and assembly analysis resulted in 785 unigenes, which were classified functionally into 23 categories according to the Gene Ontology database. Seven EST-based SSR markers were developed in this study and are expected to be useful in characterizing how this invasive species was introduced, as well as providing insights into its genetic microevolution.展开更多
To identify the water stress induced genes of upland rice cultivar IRAT109, which is resistant to drought, a subtractive cDNA library was developed from polyethylene glycol- (PEG) treated and non-treated seedlings b...To identify the water stress induced genes of upland rice cultivar IRAT109, which is resistant to drought, a subtractive cDNA library was developed from polyethylene glycol- (PEG) treated and non-treated seedlings by suppression subtractive hybridization, from which 2112 recombinant colonies were obtained, Eight hundred clones were selected randomly for sequencing analysis, and 384 unique expressed sequence tags (ESTs) were obtained, They were found to be involved in diverse biological processes, such as metabolism, transcription, signal transduction, protein synthesis and others, Notably a number of known functional genes in drought tolerance, including genes related to biosynthesis of osmoprotectants, defense against active oxygen, removal of toxic compounds, recovery of proteins and reinforcement of cell wall were also found in the study, Several genes related to deleterious responses were upregulated by PEG stress, The differential expression patterns of 11 SSH-derived ESTs were confirmed by real-time polymerase chain reaction.展开更多
By using assembled expressed sequence tags (ESTs) from 14 different eDNA libraries that contain 84 132 sequences reads, 556 Populus candidate single nucleotide polymorphisms (SNPs) were identified. Because traces ...By using assembled expressed sequence tags (ESTs) from 14 different eDNA libraries that contain 84 132 sequences reads, 556 Populus candidate single nucleotide polymorphisms (SNPs) were identified. Because traces were not available from dbEST (http://www.ncbi.nlm.nih.gov/dbEST/index.html), stringent filters were used to identify reliable candidate SNPs. Sequences analysis indicated that the main types of substitutions among candidate SNPs were A/G and T/C transitions, which accounted for 22.0% and 30.8%, respectively. One hundred and ten candidate SNPs were tested. As a result, 38 candidate SNPs were confirmed by directed sequencing of PCR products amplified from six different individuals. Thirteen new SNPs in intron regions were found and multiple SNPs were found to be located in both intron and exon regions of four contigs. Heterozygosis was found in all 47 candidate sites and five SNP sites were heterozygous in all six samples. This is the first report of SNP identification in a tree species which reveals that assembled ESTs from multiple libraries of the public database may provide a rich source of comparative sequences for an SNP search in the poplar genome.展开更多
Background Porcine liver performing efficient physiological functions in the human body is prerequisite for successful liver xenotransplantation. However, the protein differences between pig and human remain largely u...Background Porcine liver performing efficient physiological functions in the human body is prerequisite for successful liver xenotransplantation. However, the protein differences between pig and human remain largely unexplored. Therefore we investigated the liver expression profile of a highly inbred minipig line. Methods A cDNA library was constructed from liver tissue of an inbred Banna minipig. Two hundred randomly selected clones were sequenced then analysed by BLAST programme. Results Alignments of the sequences showed 44% encoded previously known porcine genes. Among the 56% unknown genes, sequences of 72 clones had high similarities with known genes of other species and the similarities to human were mostly above 0.80. The other 40 clones showing no similarity to genes in National Centre for Biotechnology Information are newly discovered, expressed sequence tags specific to liver of inbred Banna minipig. Twenty-two of the 200 clones had full length encoding regions, 38 complete 5' terminal sequences and 140 complete 3' terminal sequences.Conclusion These newly discovered expression sequences may be an important resource for research involving physiological characteristics and medical usage of inbred pigs and contribute to matching studies in xenotransplantation.展开更多
Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificia...Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificial breeding and reproduction.We performed full-length transcriptome sequencing and assembly of the genome of yellowfin seabream.A total of 68086 unigenes were obtained,with an N50 of 3391 bp on average length of 2933 bp.A total number of 50593 expressed sequence tags linked to simple sequence repeats(EST-SSR)were identified,among them dinucleotide repeats(40.6%)and AC/GT motifs(38.5%)were the most frequent.Of the 190 EST-SSRs for which PCR primer pairs were designed,150 primer pairs successfully amplified target loci and 15 SSRs showed high polymorphism.The alleles per locus ranged 6-50 on average of 25.3.The expected and observed heterozygosity varied from 0.632 to 0.969 and from 0.519 to 0.953,respectively.The polymorphic index content(PIC)values of each locus ranged 0.587-0.966 on average of 0.851.Among six yellowfin seabream population samples preliminarily tested for genetic diversity and differentiation,the Fangchenggang(FCG)population in Guangxi Province had the highest mean observed heterozygosity(H_(o))value(0.786),whereas the Zhangzhou(ZZ)population in Fujian Province had the lowest(0.678).The pairwise fixation index(Fst)values indicated significant population differentiation among six yellowfin seabream populations.This study provided evidence for the usefulness of the transcriptomic resource information and EST-SSR markers for natural resource conservation,population genetics,and breeding studies of yellowfin seabream in South China.展开更多
Objective: To screen and analyze key express sequence tags (ESTs) which were differentially displayed in every period of SD rats' primary hepatic carcinoma and reveal the molecular mechanism of carcinogenesis. Met...Objective: To screen and analyze key express sequence tags (ESTs) which were differentially displayed in every period of SD rats' primary hepatic carcinoma and reveal the molecular mechanism of carcinogenesis. Methods: Using diethylnitrosamine (DENA) as a cancerigenic agent, animal models with different phases of primary hepatic cancer were constructed in SD rats. Rats were respectively sacrificed at d 14, d 28, d 56, d 77, d 105 and d 112 after the rats received DENA by gavage, then the livers were harvested. One part of the livers was classified according to their pathological changes, while the other was reserved for molecular mechanism studies on hepatocarcinogenesis. The differentially expressed genes were isolated from both normal and morbid tissues by mRNA differential display technique (DDRT-PCR). After the fragments were sequenced, bioinformatics were .used to analyze the results. Results: Twelve differentially expressed cDNA fragments were obtained. Nine fragments had the homology with known cDNA clones, especially EST-7 was similar to BN/SsNHsdMCW mitochondrion gene and the identity was 100% which suggested EST-7 may be the part of BN/SsNHsdMCW mitochondrion gene. In contrast, other three fragments (EST-1, EST-3 and EST-5) had extremely low identity to any genes registered in GENBANK databases. Conclusions: BN/SsNHsdMCW mitochondrion gene was expressed in different periods of hepatocarcinogenesis. Moreover, EST-I, EST-3 and EST-5 were suggested to contribute to the development of rat hepatocarcinogenesis, and thus may be candidates of new targets of oncogenes or cancer suppressor genes.展开更多
For the purpose of screening and analyzing the differentially expressed genes from the salivary gland of Rhipicephalus haemaphysaloides, two salivary gland-subtracted cDNA libraries of partially fed female ticks and f...For the purpose of screening and analyzing the differentially expressed genes from the salivary gland of Rhipicephalus haemaphysaloides, two salivary gland-subtracted cDNA libraries of partially fed female ticks and fed male ticks were constructed using suppression subtractive hybridization (SSH). A total of 247 female expression sequence tags (ESTs) and 168 male ESTs were obtained from the two SSH cDNA libraries. It is predicted that 25 female ESTs and 44 female ESTs contain the 5" and 3" ends, respectively, and that 53 male ESTs and 74 male ESTs contain the 5" and 3" ends, respectively. To identify the subtraction rate of the two SSH cDNA libraries, the RT-PCR method was used to test 24 female ESTs and 21 male ESTs selected randomly but not repeatedly. The results showed that there were 13 upregulated or differentially expressed genes in the partially fed salivary gland of the female R. haemaphysaloides and that the differentially expressed rate was 54%. In addition, they indicated that there were 9 upregulated or differently expressed genes in the fed salivary gland of the male R. haemaphysaloides and that the differentially expressed rate was 43%. Putative translations of 141 (57%) female ESTs and 125 (74%) male ESTs had similarity to GenBank sequences, and 32 (23%) female ESTs and 29 (23%) male ESTs exhibited similarity to tick proteins, which showed that most of the proteins in the libraries were mainly related to the feeding blood physiology of the ticks.展开更多
Rice endosperm plays a very important role in seedling germination and determines the qualities of rice grain. Although studies on specific gene categories in endosperm have been carried out, global view of gene expre...Rice endosperm plays a very important role in seedling germination and determines the qualities of rice grain. Although studies on specific gene categories in endosperm have been carried out, global view of gene expression at a transcription level In rice endosperm Is still limited. To gain a better understanding of the global and tissue-specific gene expression profiles In rice endosperm, a cDNA library from rice endosperm of immature seeds was sequenced. A cDNA array was constructed based on the tentative unique transcripts derived from expression sequence tag (EST) assembling results and then hybridized with cDNAs from five different tissues or organs including endosperm, embryo, leaf, stem and root of rice. Significant redundancy was found for genes encoding prolamin, glutelin, allergen, and starch synthesis proteins, accounting for ~34% of the total ESTs obtained. The cDNA array revealed 87 significantly expressed genes In endosperm compared with the other four organs or tissues. These genes included 13 prolamin family proteins, 17 glutelin family proteins, 12 binding proteins, nine catalytic proteins and four ribosomal proteins, indicating a complicated biological processing in rice endosperm. In addition, Northern verification of 1,4-alpha-glucan branching enzyme detected two isoforms in rice endosperm, the larger one of which only existed in endosperm.展开更多
Paris polyphylla Smith var.yunnanensis(Franch.) Hand.-Mazz.is a rhizomatous,herbaceous,perennial plant that has been used for more than a thousand years in traditional Chinese medicine.It is facing extinction due to o...Paris polyphylla Smith var.yunnanensis(Franch.) Hand.-Mazz.is a rhizomatous,herbaceous,perennial plant that has been used for more than a thousand years in traditional Chinese medicine.It is facing extinction due to overharvesting.Steroids are the major therapeutic components in Paris roots,the commercial value of which increases with age.To date,no genomic data on the species have been available.In this study,transcriptome analysis of an 8-year-old root and a 4-year-old root provided insight into the metabolic pathways that generate the steroids.Using Illumina sequencing technology,we generated a high-quality sequence and demonstrated de novo assembly and annotation of genes in the absence of prior genome information.Approximately 87,577 unique sequences,with an average length of 614 bases,were obtained from the root cells.Using bioinformatics methods,we annotated approximately 65.51% of the unique sequences by conducting a similarity search with known genes in the National Center for Biotechnology Information's non-redundant database.The unique transcripts were functionally classified using the Gene Ontology hierarchy and the Kyoto Encyclopedia of Genes and Genomes database.Of 3082 genes that were identified as significantly differentially expressed between roots of different ages,1518(49.25%) were upregulated and 1564(50.75%) were downregulated in the older root.Metabolic pathway analysis predicted that 25 unigenes were responsible for the biosynthesis of the saponins steroids.These data represent a valuable resource for future genomic studies on this endangered species and will be valuable for efforts to genetically engineer P.polyphylla and facilitate saponin-rich plant development.展开更多
Faba bean (Vicia faba L.), one of the most important legumes in the world, evolved different types of cultivars due to its partial cross-pollination. The development of simple sequence repeat (SSR) markers from ex...Faba bean (Vicia faba L.), one of the most important legumes in the world, evolved different types of cultivars due to its partial cross-pollination. The development of simple sequence repeat (SSR) markers from expressed sequence tags (EST) provided a useful tool for investigation of its genetic diversity. The purpose of the present study was to investigate the genetic diversity of faba bean from China and Europe using EST-SSR markers. 5 031 faba bean ESTs from the NCBI database were downloaded and assembled into 1 148 unigenes. A total of 107 microsatellites in 96 unigenes were identified, indicating that merely 8.36% of sequences contained SSRs. The most abundant SSR within faba bean was tri-nucleotide repeat motif, and among all the tri-nucleotide repeats, the motif AAG/CTT was the most abundant type. Based on these results, 11 EST-SSR markers were used to assess the genetic diversity of 29 faba bean cultivars from China and Europe with two to three alleles per locus. The polymorphism information content value ranged from 0.0644 to 0.4278 with an average of 0.2919. Principal coordinate analysis (PCA) and phylogenetic clustering based on these 11 EST-SSR markers distinguished these cultivars into different groups. The results indicated that faba bean in China had a narrow genetic basis, and the additional sources of genetic cultivars/accessions should be introduced to enhance the genetic variability. The results of this study proved that the EST-SSR marker is very effective in evaluation of faba bean germplasm.展开更多
MicroRNAs(miRNA)are recently discovered endogenous,small noncoding RNAs(of 22 nucleotides)that play pivotal roles in gene regulation.They are involved in post-transcriptional control of gene expression.miRNAs are emer...MicroRNAs(miRNA)are recently discovered endogenous,small noncoding RNAs(of 22 nucleotides)that play pivotal roles in gene regulation.They are involved in post-transcriptional control of gene expression.miRNAs are emerging as important regulators of cell proliferation,development,cancer formation,stress responses,cell death and physiological conditions.Increasing evidence has demonstrated the human miRNAs bind to their target mRNA sequences with perfect or near-perfect sequence complementarily.This provides a powerful strategy for discovering potential type 2 diabetes mellitus(T2DM)targets and gives the probability to exploit them for diagnostic and therapeutic causes.About 6%of the world population is affected by T2DM,and it is recognized as a global epidemic by the World Health Organization.At present there is no valid biomarker to control or manage T2DM.Therefore,the present study applied a mature sequence of miRNAs from publicly accessible databases to identify the miRNA from T2DM expressed sequence tags,and the results are detailed and discussed below.展开更多
基金The Key Science and Technology Program of Shandong Province under contract No. 2012GHY11527Natural Science Foundation of Shandong Province under contract No. Q2007E02+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education (New Teachers) under contract No. 20070423027the Public Science and Technology Research Funds Projects of Ocean, State Oceanic Administration of the People’s Republic of China under contract No. 201105021-8
文摘Zostera marina, a monocotyledonous angiosperm, is one of the most important seagrass species. To inves- tigate the salt-tolerance mechanism and discover salt-tolerant genes in Z. marina, a cDNA library was con- structed. Single-pass sequencing of the 5' ends of 4 081 clones yielded 4 002 high quality expressed sequence tags (ESTs), which were assembled into 241 contigs and 1 673 singletons, representing 1 914 unigenes. The average length of the ESTs was 582 bp, with sizes ranging from 100-1 500 bp. Basic Local Alignment Search Tool (BLASTX) analysis revealed that 1 664 unigenes had significant homology to known genes in the Na- tional Center for Biotechnology Information (NCBI) non-redundant (nr) database (E-value≤5-10). Among them, the two most abundant genes encoded metallothionein (157 ESTs) and chlorophyll a/b-binding pro- tein (38 ESTs), accounting for 7.1% and 1.7% of the total ESTs, respectively. Using Kyoto Encyclopedia of Genes and Genomes (KEGG), 1 462 unigenes were assigned to 1 161 pathways (E-value≤5-10). A total of 938 unigenes were assigned Gene Ontology (GO) terms based on the GO hierarchy analysis, and InterProScan searches recognized 1 003 InterPro families. Three genes for metallothionein in Z. marina that belonged to Class II was identified. Results of this study will improve understanding of the molecular mechanisms of saline tolerance in Z. marina.
基金supported by the National Basic Research Program of China(2007CB116201)
文摘Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Construction of a full-length cDNA library is an effective way to understand the expression of functional genes in muscle tissues. In addition, novel genes for further research could be identified in the library. In this study, we constructed a full-length cDNA library from porcine muscle tissue. The estimated average size of the cDNA inserts was 1 076 bp, and the cDNA fullness ratio was 86.2%. A total of 1 058 unique sequences with 342 contigs (32.3%) and 716 singleton (67.7%) expressed sequence tags (EST) were obtained by clustering and assembling. Meanwhile, 826 (78.1%) ESTs were categorized as known genes, and 232 (21.9%) ESTs were categorized as unknown genes. 65 novel porcine genes that exhibit no identity in the TIGR gene index of Sus scrofa and 124 full-length sequences with unknown functions were deposited in the dbEST division of GenBank (accession numbers: EU650784-EU650788, GE843306, GH228978-GH229100). The abundantly expressed genes in porcine muscle tissue were related to muscle fiber development, energy metabolism and protein synthesis. Gene ontology analysis showed that sequences expressed in porcine muscle tissue contained a high percentage of binding activity, catalytic activity, structural molecule activity and motor activity, which involved mainly in metabolic, cellular and developmental process, distributed mainly in intracellular region. The sequence data generated in this study would provide valuable information for identifying porcine genes expressed in muscle tissue and help to advance the study on the structure and function of genes in pigs.
基金supported by the China Agriculture Research System (CARS-30)
文摘Vitis amurensis is a valuable resource for wine production. Ripening of the grape berry is the key phase which determines the com- position of wine. To better understand the gene expression that manifest in V. amurensis berry skins during the ripening, cDNA library of V. amurensis berry skins was constructed. A total of 935 high quality ex- pressed sequence tags (ESTs) were obtained from the library. These ESTs represent 636 unigenes, including 108 contigs and 528 singletons. The EST analysis was performed and genes were assigned to functional categories according to their primary BLAST match. Of these 25.35% were involved with metabolism, 6.27% with cell rescue and defense, 6.84% energy, 11.68% protein synthesis, 18.8% protein activity regula- tion, 11.11% cell structure, 7.98% transport, 6.27% transcription and the remaining 5.7% were signal transduction. The generated ESTs were characterized by the gene ontology analysis and were categorized ac- cording to its cellular component, molecular function and biological process. In the cDNA library, some genes are relevant to the biosynthesis of anthocyanins, while some genes are related to grape berry maturation.
基金supported by the Chinese National Key Project of Basic Research(G20000161)
文摘In order to study the expression of function gene and its effect on metabolic control and other physiological function in liver, 438 expressed sequence tags (ESTs) were determined, which were from a cD-NA library of porcine liver tissue. The results showed that the nucleotide sequences of 186 ESTs have already presented in GenBank database, and 37 ESTs could be found the homology with human and other species, while the others were not identified. 45 full length insertion of the clones randomly isolated from cDNA library were also completely sequenced with different size, and the results showed that 19 of them were function-known genes, 11 had no open reading frame ( ORF )at all and 15 had ORF but the function were not elucidated yet.
文摘In order to detect the molecular mechanism of heterosis in pigs, the mRNA differential display technique was performedto investigate the differences of gene expression in the backfat tissue from Meishan, Large White and MeishanLargeWhite cross pigs. Nine 3'-end anchored primers in combination with ten 5'-end arbitrary primers were used to perform thedifferential display PCR and nearly 3 000 reproducible bands were examined. Fifteen expressed sequence tags that weredifferentially expressed were isolated and then identified through semi-quantitative RT-PCR. BLAST analysis revealedthat the fifteen expressed sequence tags (ESTs) were not homologous to any of the known porcine genes or ESTs. Thesenovel ESTs were then submitted to GenBank.
基金the Program for New Century Excellent Talents in University (NCET-06-0810)Young Scholars Foundation from the Science and Technology Committee of Sichuan,China (2008-31-371) for their financial support
文摘Gymnadenia conopsea,an alpine Orchidaceae plant,was one of the widely used Tibetan traditional medicines.In this study,we sequenced total 105 expressed sequence tags (ESTs) from a full-length cDNA expression library constructed by the Oligo-capping technique.The further bioinformatic analyses suggested that the 65 represented unique sequences showed high homology to previously identified genes in other plants:30 sequences matched to other uncharacterized expressed sequence tags (ESTs),and 10 sequences showed no good matches to available sequences in DNA databases.Gene ontology annotation by InterProScan indicated that many of these cDNAs (7 percent) have no known molecular functions and may be unique to G.conopsea.Fifty-five ESTs with matched proteins were involved in a series of diverse functions,in which molecular function such as 'binding' (42.9 percent) and 'catalytic activity' (25.0 percent) were the most frequent functions of the cDNAs.This cDNA library provided a critical basis for further investigation of functional genes expression under cold stress in this alpine species.In addition,13 ESTs-based polymerase chain reaction (PCR) primers were designed and can also be used for genotypic identification and for the genetic diversity analysis of G.conopsea and its closely related species.
基金Supported by the Key Forestry Public Welfare Project(201304102)the Key Project for Universities of Jiangsu Province(10KJA180018)+1 种基金enabled by the Program for Innovative Research Team in Universities of Jiangsu Province and the Educational Department of Chinathe Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘In this study,64 498 ESTs of Melampsoraspp.was assembled into 1 998 contigs,and 604SSR loci were detected on these contigs,with 736.6 bp containing one SSR on average.Among these SSRs,trinucleotide repeats were the most abundant repeats(44.70%).As for the composition of microsatellites, AC and AT repeats were the richest motif in dinucleotide repeats,and AGT and AAG repeats were the most frequent motifs in trinucleotide repeats,whereas(AAAN) n and(AAAAN) n repeats were dominant in tetranucleotide and pentanucleotide repeats,respectively.All the dominant repeat motifs of different types of SSRs were rich in A and T.In EST sequences of Melampsoraspp.genome,microsatellites longer than 20 bp accounted for about 15.07%.It was noticeable that microsatellites were highly rich in the expressed sequences of Melampsoraspp.genome,which implied that SSRs played a significant role in triggering the gene mutation in Melampsoraspp.genome.A total of 455 SSR primers were designed according to the detected microsatellites using Primer 5.0 and Oligo 6. 0,and 30 primer pairs were randomly selected for amplification test.Among these primer pairs,27 primer pairs succeed in amplification,with a successful rate of 90%.Eight primer pairs generated polymorphic fingerprints in Melampsoraspp.collected from different poplar genotypes,accounting for 26.7% of the total primer pairs.The EST-SSR markers developed fromMelampsoraspp.EST sequences provided important marker resources for studying Melampsoraspp.from the aspects of pathogen identification and survey of genetic variation.
基金supported by grants from the China National Basic Research Program(2010CB126002)the National Natural Science Foundation of China(90717009)the 111 Project funded by the Chinese Ministry of Education
文摘We assembled a total of 297,239 Gossypium hirsutum (Gh, a tetraploid cotton, AADD) expressed sequence tag (EST) sequences that were available in the National Center for Biotechnology Information database, with reference to the recently published G. raimondii (Gr, a diploid cotton, DD) genome, and obtained 49,125 UniGenes. The average lengths of the U niGenes were increased from 804 and 791 bp in two previous EST assemblies to 1,019 bp in the current analysis. The number of putative cotton UniGenes with lengths of 3 kb or more increased from 25 or 34 to 1,223. As a result, thousands of originally independent G. hirsutum ESTs were aligned to produce large contigs encoding transcripts with very long open reading frames, indicating that the G. raimondii genome sequence provided remarkable advantages to assemble the tetraploid cotton transcriptome. Significant different distribution patterns within several GO terms, including transcription factor activity, were observed between D- and A-derived assemblies. Tran- scriptome analysis showed that, in a tetraploid cotton cell, 29,547 UniGenes were possibly derived from the D subgenome while another 19,578 may come from the A subgenome. Finally, some of the in silico data were confirmed by reverse transcription polymerase chain reaction experiments to show the changes in transcript levels for several gene families known to play key role in cotton fiber development. We believe that our work provides a useful platform for functional and evolutionary genomic studies in cotton.
基金supported by funds provided by the Georgia Agricultural Commodity Commission for Peanuts,the National Peanut Board and the Peanut Foundation
文摘Low genetic diversity makes peanut (Arachis hypogaea L.) very vulnerable to plant pathogens, causing severe yield loss and reduced seed quality. Several hundred partial genomic DNA sequences as nucleotide-binding-site leucine-rich repeat (NBS-LRR) resistance genes (R) have been identified, but a small portion with expressed transcripts has been found. We aimed to identify resistance gene analogs (RGAs) from peanut expressed sequence tags (ESTs) and to develop polymorphic markers. The protein sequences of 54 known R genes were used to identify homologs from peanut ESTs from public databases. A total of 1,053 ESTs corresponding to six different classes of known R genes were recovered, and assembled 156 contigs and 229 singletons as peanut-expressed RGAs. There were 69 that encoded for NBS-LRR proteins, 191 that encoded for protein kinases, 82 that encoded for LRR-PK/transmembrane proteins, 28 that encoded for Toxin reductases, 11 that encoded for LRR-domain containing proteins and four that encoded for TM-domain containing proteins. Twenty-eight simple sequence repeats (SSRs) were identified from 25 peanut expressed RGAs. One SSR polymorphic marker (RGA121) was identified. Two polymerase chain reaction-based markers (Ahsw-1 and Ahsw-2) developed from RGA013 were homologous to the Tomato Spotted Wilt Virus (TSWV) resistance gene. All three markers were mapped on the same linkage group AhIV. These expressed RGAs are the source for RGA-tagged marker development and identification of peanut resistance genes.
文摘The cotton mealybug, Phenacoccus solenopsis Tinsley, is a serious and invasive pest. At present, genetic resources for studying P. solenopsis are limited, and this negatively affects genetic research on the organism and, consequently, translational work to improve management of this pest. In the present study, expressed sequence tags (ESTs) were analyzed from a normalized complementary DNA library of/?. solenopsis. In addition, EST-derived microsatellite loci (also known as simple sequence repeats or SSRs) were isolated and characterized. A total of 1107 high-quality ESTs were acquired from the library. Clustering and assembly analysis resulted in 785 unigenes, which were classified functionally into 23 categories according to the Gene Ontology database. Seven EST-based SSR markers were developed in this study and are expected to be useful in characterizing how this invasive species was introduced, as well as providing insights into its genetic microevolution.
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education of the Ministry of Education of China(20030019004)the National Natural Science Foundation of China(30250009).
文摘To identify the water stress induced genes of upland rice cultivar IRAT109, which is resistant to drought, a subtractive cDNA library was developed from polyethylene glycol- (PEG) treated and non-treated seedlings by suppression subtractive hybridization, from which 2112 recombinant colonies were obtained, Eight hundred clones were selected randomly for sequencing analysis, and 384 unique expressed sequence tags (ESTs) were obtained, They were found to be involved in diverse biological processes, such as metabolism, transcription, signal transduction, protein synthesis and others, Notably a number of known functional genes in drought tolerance, including genes related to biosynthesis of osmoprotectants, defense against active oxygen, removal of toxic compounds, recovery of proteins and reinforcement of cell wall were also found in the study, Several genes related to deleterious responses were upregulated by PEG stress, The differential expression patterns of 11 SSH-derived ESTs were confirmed by real-time polymerase chain reaction.
基金the National Natural Science Foundation of China,the Jiangsu Provincial Hi-Tech Research Project,the Jiangsu Provincial Graduate Innovation Project
文摘By using assembled expressed sequence tags (ESTs) from 14 different eDNA libraries that contain 84 132 sequences reads, 556 Populus candidate single nucleotide polymorphisms (SNPs) were identified. Because traces were not available from dbEST (http://www.ncbi.nlm.nih.gov/dbEST/index.html), stringent filters were used to identify reliable candidate SNPs. Sequences analysis indicated that the main types of substitutions among candidate SNPs were A/G and T/C transitions, which accounted for 22.0% and 30.8%, respectively. One hundred and ten candidate SNPs were tested. As a result, 38 candidate SNPs were confirmed by directed sequencing of PCR products amplified from six different individuals. Thirteen new SNPs in intron regions were found and multiple SNPs were found to be located in both intron and exon regions of four contigs. Heterozygosis was found in all 47 candidate sites and five SNP sites were heterozygous in all six samples. This is the first report of SNP identification in a tree species which reveals that assembled ESTs from multiple libraries of the public database may provide a rich source of comparative sequences for an SNP search in the poplar genome.
基金This study was supported by grants from the National Natural Science Foundation of China(No.30270679)National Basic Research Program of China(No.2003CB515504)National Basic Research Program of China(No.2004CCA01800).
文摘Background Porcine liver performing efficient physiological functions in the human body is prerequisite for successful liver xenotransplantation. However, the protein differences between pig and human remain largely unexplored. Therefore we investigated the liver expression profile of a highly inbred minipig line. Methods A cDNA library was constructed from liver tissue of an inbred Banna minipig. Two hundred randomly selected clones were sequenced then analysed by BLAST programme. Results Alignments of the sequences showed 44% encoded previously known porcine genes. Among the 56% unknown genes, sequences of 72 clones had high similarities with known genes of other species and the similarities to human were mostly above 0.80. The other 40 clones showing no similarity to genes in National Centre for Biotechnology Information are newly discovered, expressed sequence tags specific to liver of inbred Banna minipig. Twenty-two of the 200 clones had full length encoding regions, 38 complete 5' terminal sequences and 140 complete 3' terminal sequences.Conclusion These newly discovered expression sequences may be an important resource for research involving physiological characteristics and medical usage of inbred pigs and contribute to matching studies in xenotransplantation.
基金Supported by the National Key R&D Program of China (No. 2019YFD0901202)the Key-Area Research and Development Program of Guangdong Province (No. 2021B0202020002)+1 种基金the China Postdoctoral Science Foundation (No. 2021M693677)the Yellow Fin Bream Seed System Building Project (2021)
文摘Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificial breeding and reproduction.We performed full-length transcriptome sequencing and assembly of the genome of yellowfin seabream.A total of 68086 unigenes were obtained,with an N50 of 3391 bp on average length of 2933 bp.A total number of 50593 expressed sequence tags linked to simple sequence repeats(EST-SSR)were identified,among them dinucleotide repeats(40.6%)and AC/GT motifs(38.5%)were the most frequent.Of the 190 EST-SSRs for which PCR primer pairs were designed,150 primer pairs successfully amplified target loci and 15 SSRs showed high polymorphism.The alleles per locus ranged 6-50 on average of 25.3.The expected and observed heterozygosity varied from 0.632 to 0.969 and from 0.519 to 0.953,respectively.The polymorphic index content(PIC)values of each locus ranged 0.587-0.966 on average of 0.851.Among six yellowfin seabream population samples preliminarily tested for genetic diversity and differentiation,the Fangchenggang(FCG)population in Guangxi Province had the highest mean observed heterozygosity(H_(o))value(0.786),whereas the Zhangzhou(ZZ)population in Fujian Province had the lowest(0.678).The pairwise fixation index(Fst)values indicated significant population differentiation among six yellowfin seabream populations.This study provided evidence for the usefulness of the transcriptomic resource information and EST-SSR markers for natural resource conservation,population genetics,and breeding studies of yellowfin seabream in South China.
基金supported by the Key Program for Science and Technology Development of Henan Province [122102310174]the Zoology Key Subject of Henan Province
文摘Objective: To screen and analyze key express sequence tags (ESTs) which were differentially displayed in every period of SD rats' primary hepatic carcinoma and reveal the molecular mechanism of carcinogenesis. Methods: Using diethylnitrosamine (DENA) as a cancerigenic agent, animal models with different phases of primary hepatic cancer were constructed in SD rats. Rats were respectively sacrificed at d 14, d 28, d 56, d 77, d 105 and d 112 after the rats received DENA by gavage, then the livers were harvested. One part of the livers was classified according to their pathological changes, while the other was reserved for molecular mechanism studies on hepatocarcinogenesis. The differentially expressed genes were isolated from both normal and morbid tissues by mRNA differential display technique (DDRT-PCR). After the fragments were sequenced, bioinformatics were .used to analyze the results. Results: Twelve differentially expressed cDNA fragments were obtained. Nine fragments had the homology with known cDNA clones, especially EST-7 was similar to BN/SsNHsdMCW mitochondrion gene and the identity was 100% which suggested EST-7 may be the part of BN/SsNHsdMCW mitochondrion gene. In contrast, other three fragments (EST-1, EST-3 and EST-5) had extremely low identity to any genes registered in GENBANK databases. Conclusions: BN/SsNHsdMCW mitochondrion gene was expressed in different periods of hepatocarcinogenesis. Moreover, EST-I, EST-3 and EST-5 were suggested to contribute to the development of rat hepatocarcinogenesis, and thus may be candidates of new targets of oncogenes or cancer suppressor genes.
基金the National Natural Science Foundation of China (31172095)
文摘For the purpose of screening and analyzing the differentially expressed genes from the salivary gland of Rhipicephalus haemaphysaloides, two salivary gland-subtracted cDNA libraries of partially fed female ticks and fed male ticks were constructed using suppression subtractive hybridization (SSH). A total of 247 female expression sequence tags (ESTs) and 168 male ESTs were obtained from the two SSH cDNA libraries. It is predicted that 25 female ESTs and 44 female ESTs contain the 5" and 3" ends, respectively, and that 53 male ESTs and 74 male ESTs contain the 5" and 3" ends, respectively. To identify the subtraction rate of the two SSH cDNA libraries, the RT-PCR method was used to test 24 female ESTs and 21 male ESTs selected randomly but not repeatedly. The results showed that there were 13 upregulated or differentially expressed genes in the partially fed salivary gland of the female R. haemaphysaloides and that the differentially expressed rate was 54%. In addition, they indicated that there were 9 upregulated or differently expressed genes in the fed salivary gland of the male R. haemaphysaloides and that the differentially expressed rate was 43%. Putative translations of 141 (57%) female ESTs and 125 (74%) male ESTs had similarity to GenBank sequences, and 32 (23%) female ESTs and 29 (23%) male ESTs exhibited similarity to tick proteins, which showed that most of the proteins in the libraries were mainly related to the feeding blood physiology of the ticks.
基金the Zhejiang Provincial Science and Technology Project(2005C22002)
文摘Rice endosperm plays a very important role in seedling germination and determines the qualities of rice grain. Although studies on specific gene categories in endosperm have been carried out, global view of gene expression at a transcription level In rice endosperm Is still limited. To gain a better understanding of the global and tissue-specific gene expression profiles In rice endosperm, a cDNA library from rice endosperm of immature seeds was sequenced. A cDNA array was constructed based on the tentative unique transcripts derived from expression sequence tag (EST) assembling results and then hybridized with cDNAs from five different tissues or organs including endosperm, embryo, leaf, stem and root of rice. Significant redundancy was found for genes encoding prolamin, glutelin, allergen, and starch synthesis proteins, accounting for ~34% of the total ESTs obtained. The cDNA array revealed 87 significantly expressed genes In endosperm compared with the other four organs or tissues. These genes included 13 prolamin family proteins, 17 glutelin family proteins, 12 binding proteins, nine catalytic proteins and four ribosomal proteins, indicating a complicated biological processing in rice endosperm. In addition, Northern verification of 1,4-alpha-glucan branching enzyme detected two isoforms in rice endosperm, the larger one of which only existed in endosperm.
基金supported by the National Natural Science Foundation of China(81473310,31260075,31560085)
文摘Paris polyphylla Smith var.yunnanensis(Franch.) Hand.-Mazz.is a rhizomatous,herbaceous,perennial plant that has been used for more than a thousand years in traditional Chinese medicine.It is facing extinction due to overharvesting.Steroids are the major therapeutic components in Paris roots,the commercial value of which increases with age.To date,no genomic data on the species have been available.In this study,transcriptome analysis of an 8-year-old root and a 4-year-old root provided insight into the metabolic pathways that generate the steroids.Using Illumina sequencing technology,we generated a high-quality sequence and demonstrated de novo assembly and annotation of genes in the absence of prior genome information.Approximately 87,577 unique sequences,with an average length of 614 bases,were obtained from the root cells.Using bioinformatics methods,we annotated approximately 65.51% of the unique sequences by conducting a similarity search with known genes in the National Center for Biotechnology Information's non-redundant database.The unique transcripts were functionally classified using the Gene Ontology hierarchy and the Kyoto Encyclopedia of Genes and Genomes database.Of 3082 genes that were identified as significantly differentially expressed between roots of different ages,1518(49.25%) were upregulated and 1564(50.75%) were downregulated in the older root.Metabolic pathway analysis predicted that 25 unigenes were responsible for the biosynthesis of the saponins steroids.These data represent a valuable resource for future genomic studies on this endangered species and will be valuable for efforts to genetically engineer P.polyphylla and facilitate saponin-rich plant development.
基金supported by the Zhejiang Provincial Science and Technology Program, China (2007C32013)the Natural Science Foundation of Zhejiang Province, China (Y3090660)
文摘Faba bean (Vicia faba L.), one of the most important legumes in the world, evolved different types of cultivars due to its partial cross-pollination. The development of simple sequence repeat (SSR) markers from expressed sequence tags (EST) provided a useful tool for investigation of its genetic diversity. The purpose of the present study was to investigate the genetic diversity of faba bean from China and Europe using EST-SSR markers. 5 031 faba bean ESTs from the NCBI database were downloaded and assembled into 1 148 unigenes. A total of 107 microsatellites in 96 unigenes were identified, indicating that merely 8.36% of sequences contained SSRs. The most abundant SSR within faba bean was tri-nucleotide repeat motif, and among all the tri-nucleotide repeats, the motif AAG/CTT was the most abundant type. Based on these results, 11 EST-SSR markers were used to assess the genetic diversity of 29 faba bean cultivars from China and Europe with two to three alleles per locus. The polymorphism information content value ranged from 0.0644 to 0.4278 with an average of 0.2919. Principal coordinate analysis (PCA) and phylogenetic clustering based on these 11 EST-SSR markers distinguished these cultivars into different groups. The results indicated that faba bean in China had a narrow genetic basis, and the additional sources of genetic cultivars/accessions should be introduced to enhance the genetic variability. The results of this study proved that the EST-SSR marker is very effective in evaluation of faba bean germplasm.
文摘MicroRNAs(miRNA)are recently discovered endogenous,small noncoding RNAs(of 22 nucleotides)that play pivotal roles in gene regulation.They are involved in post-transcriptional control of gene expression.miRNAs are emerging as important regulators of cell proliferation,development,cancer formation,stress responses,cell death and physiological conditions.Increasing evidence has demonstrated the human miRNAs bind to their target mRNA sequences with perfect or near-perfect sequence complementarily.This provides a powerful strategy for discovering potential type 2 diabetes mellitus(T2DM)targets and gives the probability to exploit them for diagnostic and therapeutic causes.About 6%of the world population is affected by T2DM,and it is recognized as a global epidemic by the World Health Organization.At present there is no valid biomarker to control or manage T2DM.Therefore,the present study applied a mature sequence of miRNAs from publicly accessible databases to identify the miRNA from T2DM expressed sequence tags,and the results are detailed and discussed below.