Genome-Wide Identification of ALDH Gene Family under Salt and Drought Stress in Phaseolus vulgaris

Background:Aldehyde dehydrogenase(ALDH)genes constitute an important family of supergenes that play key roles in synthesizing various biomolecules and maintaining cellular homeostasis by catalyzing the oxidation of aldehyde products.With climate change increasing the exposure of plants to abiotic stresses such as salt and drought,ALDH genes have been identified as important contributors to stress tolerance.In particular,they help to reduce stress-induced lipid peroxidation.Objectives:This study aims to identify and characterize members of the ALDH supergene family in Phaseolus vulgaris through a genome-wide bioinformatic analysis and investigate their role in response to abiotic stressors such as drought and salt stress.Methods:Genome-wide identification of 26 ALDH genes in P.vulgaris was performed using bioinformatics tools.The identified ALDH proteins were ana-lyzed for molecular weight,amino acid number,and exon number.Phylogenetic analysis was performed to clas-sify P.vulgaris,Arabidopsis thaliana,and Glycine max ALDH proteins into different groups.Strong links between these genes and functions related to growth,development,stress responses,and hormone signaling were identified by cis-element analysis in promoter regions.In silico expression,analysis was performed to assess gene expression levels in different plant tissues.Results:RT-qPCR results showed that the expression of ALDH genes was signif-icantly altered under drought and salt stress in beans.This study provides a comprehensive characterization of the ALDH supergene family in P.vulgaris,highlighting their potential role in abiotic stress tolerance.Conclusion:Thesefindings provide a basis for future research on the functional roles of ALDH genes in enhancing plant resis-tance to environmental stressors.

Genome-wide identification and expression analysis of NIN-like Protein(NLP)genes reveals their potential roles in the response to nitrate signaling in watermelon

To balance the relationship between high yield and low nitrogen supply,the nitrogen utilization efficiency of watermelon needs to be improved urgently.Nodule inception-like Protein(NLP)transcription factors play a key node role in nitrate response and growth and development of plant,however,comprehensive analysis of the NLP gene family in watermelon is unclear.This study explored the functional classification,evolutionary characteristics,and expression profile of the ClNLP gene family.Three ClNLPs were categorized into three groups according to their gene structure and phylogeny.All of them contained the conserved RWP-RK and PB1 domains.Evolutionary analysis of ClNLPs revealed that ClNLP1 and ClNLP3 underwent strong purified selection.In addition,cis-acting elements related to plant hormones and abiotic stresses were present in the ClNLP promoter.According to tissue-specific analysis ClNLP was widely expressed in roots,stems,leaves,flowers and fruits,and ClNLP1 was significantly induced in the roots of different nitrogen utilization varieties under different nitrate nitrogen supply.The SRTING functional protein association network suggested that ClNLP1 is associated with most genes,such as NRT1.1,NRT2.1,NIA1,and NIR1,and the dual-luciferase reporter assay found that ClNLP1 positively regulates the expression of ClNRT2.1.We speculated that ClNLP1 might play a central role in regulating the response of watermelon to nitrate nitrogen.

Genome-wide Identification and Analysis of MVD Gene Family in Euphorbiaceae Plants

The mevalonate diphosphate deearboxylase （MVD） is an essential enzyme in mevalonate （MVA） pathway that catalyzes the irreversible Mg2＋ -ATP de- pendent decarboxylation of 6-carben compound mevalonate-5-diphosphate （MVAPP） into 5-carbon isopentenyl diphosphate （ IPP）, the building block of sterol and isoprenoid biosynthesis. In this study, based on the published geanme sequences and ESTs, a genome-wide search was carried out for the first time to identify MVD gene family in four genome-sequenced Euphorbiaceae plants, i.e. castor bean （ Ricinus communis）, physic nut （ Jatropha curcas）, cassava （Manihot esculenta） and rubber tree （Hevea brasiliensis）, and to analyze the gene structure and phylogenetic characteristics. According to the experimental results, 1, 1,2 and 2 MVD genes, which all contain 9 introns, were identh＇ied from castor bean, physic nut, cassava and rubber tree, respectively. Homology analysis indicates that MVD genes are widely distributed in eukaryotes, some archaea and eubacteria, which suggests an early origin of this gerte family. Although MVD genes were identified in most green plants, no homologous genes were found in unicellular green algae. In most genome-sequenced plants including castor bean and physic nut, a single copy of MVD gene was found; however, in cassava and rubber tree, two copies were identified just like that in moss, maize, Arabidopsis and poplar. ＂In castor bean, digital expression profiling suggests that in five examined tissues, i.e. leaf, flower, II/III stage endosperm, V/VI stage endosperm and seed, RcPMK was expressed strongly in flower and II/III stage endosperm, moderately in V/VI stage endosperm and leaf, and weakly in seed.

Genome-wide identification and expression analysis of NtbHLH gene family in tobacco(Nicotiana tabacum)and the role of NtbHLH86 in drought adaptation

The bHLH transcription factors play pivotal roles in plant growth and development,production of secondary metabolites and responses to various environmental stresses.Although the bHLH genes have been well studied in model plant species,a comprehensive investigation of the bHLH genes is required for tobacco with newly obtained high-quality genome.In the present study,a total of 309 NtbHLH genes were identified and can be divided into 23 subfamilies.The conserved amino acids which are essential for their function were predicted for the NtbHLH proteins.Moreover,the NtbHLH genes were conserved during evolution through analyzing the gene structures and conserved motifs.A total of 265 NtbHLH genes were localized in the 24 tobacco chromosomes while the remained 44 NtbHLH genes were mapped to the scaffolds due to the complexity of tobacco genome.Moreover,transcripts of NtbHLH genes were obviously tissue-specific expressed from the gene-chip data from 23 tobacco tissues,and expressions of 20 random selected NtbHLH genes were further confirmed by quantitative real-time PCR,indicating their potential functions in the plant growth and development.Importantly,overexpressed NtbHLH86 gene confers improve drought tolerance in tobacco indicating that it might be involved in the regulation of drought stress.Therefore,our findings here provide a valuable information on the characterization of NtbHLH genes and further investigation of their functions in tobacco.

Genome-wide identification and analysis of the regulation wheat DnaJ family genes following wheat yellow mosaic virus infection

The co-chaperone DnaJ plays an important role in protein folding and regulation of various physiological activities, and participates in several pathological processes. DnaJ has been extensively studied in many species including humans,drosophila, mushrooms, tomatoes, and Arabidopsis. However, few studies have examined the role of DnaJ in wheat(Triticum aestivum), and the interaction mechanism between TaDnaJs and plant viruses. Here, we identified 236 TaDnaJs and performed a comprehensive genome-wide analysis of conserved domains, gene structure and protein motifs, chromosomal positions and duplication relationships, and cis-acting elements. We grouped these Ta Dna Js according to their domains, and randomly selected six genes from the groups for tissue-specific analysis, and expression profiles analysis under hormone stress, and 17 genes for plant virus infection stress. In qRT-PCR, we found that among the 17 TaDnaJ genes tested, 16 genes were up-regulated after wheat yellow mosaic virus(WYMV) infection, indicating that the TaDnaJ family is involved in plant defense response. Subsequent yeast two-hybrid assays verified the WYMV NIa, NIb and 7 KD proteins interacted with TaDJC(TraesCS7 A02 G506000), which had the most significant changes in gene expression levels after WYMV infection.Insights into the molecular mechanisms of Ta Dna J-mediated stress tolerance and sensitivity could inform different strategies designed to improve crop resistance to abiotic and biotic stress. This study provides a basis for future investigation of the TaDnaJ family and plant defense mechanisms.

Genome-wide identification and analysis of cytokinin dehydrogenase/oxidase(CKX) family genes in Brassica oleracea L.reveals their involvement in response to Plasmodiophora brassicae infections

Cytokinins are a class of phytohormones that promote cell division and differentiation and are thought to affect plant immunity to multiple pathogens.However,a comprehensive analysis of cytokinin dehydrogenase/oxidase(CKX)family genes in cabbage has not been reported.In this study,a total of 36 CKX genes were identified using a genome-wide search method.Phylogenetic analysis classified these genes into three groups.They were distributed unevenly across nine chromosomes in B.oleracea,and 15 of them did not contain any introns.The results of colinearity analysis showed that 36 CKX gene in Arabidopsis was present in several copies in the Brassica oleracea genome.An analysis of cisacting elements indicated that all genes possessed at least one stress or hormone responsive cis-acting element.A heatmap of CKX gene expression showed the patterns of expression of these genes in various tissues and organs.Three genes(Bol028363,Bol031036 and Bol018140)were relatively highly expressed in all of the investigated tissues under normal conditions,showing the expression profile of housekeeping genes.Generally,the expression patterns of CKX genes in Jingfeng 1 and Xiangan 336 were quite different under the same treatment.Notably,three genes(Bol020547,Bol028392 and Bol045724)were significantly down-regulated and up-regulated in the susceptible and resistant material,respectively,after inoculation,which may indicate their crucial roles in resistance to clubroot disease.The results provide insights for better understanding the roles of CKX genes in the B.oleracea–P.brassicae interaction.

Genome-wide identification and co-expression analysis of GDSL genes related to suberin formation during fruit russeting in pear

Glycine-aspartic acid–serine-leucine(GDSL)type lipases/esterases genes play critical roles in plant development and are related to the responses to abiotic and biotic stress.However,little is known about the GDSL family in pear(Pyrus spp.).Studies have shown GDSL-domain proteins play key roles in suberin deposition.Suberin deposition in the fruit epidermis,also called russeting,is an important defect that negatively affects consumer's appeal in some fruit species,such as pear,apple and grapevine.Fruit russeting is mainly associated with cuticle microcracking and suberin accumulation in the inner part of the epidermal cell walls.To gain insight into the role of the GDSL gene family in suberin deposition and russet development in pear,we performed a genome-wide characterization of the GDSL family,including their identification,chromosomal localization,phylogenetic relationships,and expression patterns,in different tissues/organs in pear.One hundred and thirteen GDSL-type lipases/esterases genes were identified in the pear genome,and a phylogenetic analysis revealed that GDSL family can be classified into four distinct groups.Thirty GDSL genes were co-expressed with five homolog pear genes of three well-known suberin biosynthesis Arabidopsis genes(AtGPAT5,AtASFT,and AtCYP86B1)in the transcriptional co-expression network during pear fruit development.Among the 30 co-expressed GDSL genes,twelve genes were further analyzed by quantitative Real-time PCR,and the results showed the expression levels of the 12 genes were different between the russet exocarp and green exocarp of sand pear at different fruit development stages.Our study provides a detailed overview of the GDSL gene family and lays the foundation for future functional characterization of GDSL genes in P.bretschneideri.

Genome-wide identification and characterization of the JAZ gene family and its expression patterns under various abiotic stresses in Sorghum bicolor

The jasmonate ZIM domain(JAZ)protein belongs to the TIFY((TIF[F/Y]XG)domain protein)family,which is composed of several plant-specific proteins that play important roles in plant growth,development,and defense responses.However,the mechanism of the sorghum JAZ family in response to abiotic stress remains unclear.In the present study,a total of 17 JAZ genes were identified in sorghum using a Hidden Markov Model search.In addition,real-time quantification polymerase chain reaction(RT-qPCR)was used to analyze the gene expression patterns under abiotic stress.Based on phylogenetic tree analysis,the sorghum JAZ proteins were mainly divided into nine subfamilies.A promoter analysis revealed that the SbJAZ family contains diverse types of promoter cis-acting elements,indicating that JAZ proteins function in multiple pathways upon stress stimulation in plants.According to RT-qPCR,SbJAZ gene expression is tissuespecific.Additionally,under cold,hot,polyethylene glycol,jasmonic acid,abscisic acid,and gibberellin treatments,the expression patterns of SbJAZ genes were distinctly different,indicating that the expression of SbJAZ genes may be coordinated with different stresses.Furthermore,the overexpression of SbJAZ1 in Escherichia coli was found to promote the growth of recombinant cells under abiotic stresses,such as PEG 6000,NaCl,and 40℃ treatments.Altogether,our findings help us to better understand the potential molecular mechanisms of the SbJAZ family in sorghum in response to abiotic stresses.

Genome-wide identification of apple auxin receptor family genes and functional characterization of MdAFB1

The auxin receptor(TIR1/AFBs)family encodes the F-box protein subunit,which is involved in the formation of the E3 ubiquitin ligase SCFTIR1/AFBs complex,a key component of the auxin signaling pathway.However,there are few studies on the auxin receptor family in apple(Malus×domestica).In this study,eight MdAFBs were identified,and phylogenetic analysis showed that they were classified into four groups and distributed on eight chromosomes.Herein,a comprehensive analysis of the MdAFB gene family was conducted to identify cis-acting elements,gene structures,protein structures,aligned sequences,conserved motifs,conserved amino acids,and the protein–protein interaction network.The results of yeast two-hybrid assays showed that MdAFB1 interacted with three auxin repressor proteins.The results of qRT-PCR showed that MdAFB1 responded to osmotic and salt stress.The overexpression of MdAFB1 increased osmotic and salt resistance in apple calli,and the ectopic expression of MdAFB1 enhanced osmotic and salt tolerance in Arabidopsis.This study provided a basis for the identification of auxin receptor genes in apple and their functions in mediating osmotic and salt stress.

Genome-wide identification and expression analysis of GDSL esterase/lipase genes in tomato

The GDSL esterase/lipase family contains many functional genes that perform important biological functions in growth and development, morphogenesis, seed oil synthesis, and defense responses in plants. The expression of GDSL esterase/lipase genes can respond to biotic and abiotic stresses. Although GDSL esterase/lipase family genes have been identified and studied in other plants, they have not been identified and their functions remain unclear in tomato. This study is the first to identify 80 GDSL esterase/lipase family genes in tomato, which were named SlGELP1–80. These genes were mapped to their positions on the chromosomes and their physical and chemical properties, gene structure, phylogenetic relationships, collinear relationships, and cis-acting elements were analyzed. The spatiotemporal expression characteristics of the Sl GELP genes in tomato were diverse. In addition, RNA-seq analysis indicated that the expression patterns of the SlGELP genes in tomato differed before and after inoculation with Stemphylium lycopersici. qRT-PCR was used to analyze the expression of five Sl GELP genes after treatments with S. lycopersici, salicylic acid and jasmonic acid. Finally, this study was the first to identify and analyze GDSL esterase/lipase family genes in tomato via bioinformatics approaches, and these findings provide new insights for improving the study of plant disease resistance.

Genome-wide identification of NAC gene family and expression analysis under abiotic stresses in Salvia miltiorrhiza

NAC(NAM,ATAF,CUC)is a class of transcription factors involved in plant growth regulation,abiotic stress responses,morphogenesis and metabolism.Salvia miltiorrhiza is an important Chinese medicinal herb,but the characterization of NAC genes in this species is limited.In this study,based on the Salvia miltiorrhiza genomic databases,82 NAC transcription factors were identified,which were divided into 14 groups.Meanwhile,phylogenetic analysis,gene structure,chromosomal localization and potential role of SmNACs in abiotic stress conditions were also studied.The results revealed that some SmNACs had different structures than others,which advised that these genes may have multiple/distinct functions.Real-time quantitative polymerase chain reaction(RT-qPCR)analysis showed that SmNACs exhibited differential expression patterns under salt and drought stress.The NaCl induced salinity treatments modulated the expression of several SmNAC genes more in roots compared with leaves.Conversely,under drought stress conditions,more genes were upregulated in leaves compared with roots.These results will be useful for the further study involved in the functional characteristics of SmNAC genes,especially in response to salt and drought stresses,thereby may facilitate genetic breeding in Salvia miltiorrhiza.

Genome-Wide Identification and Expression Profiling of the Shaker K+ Channel and HAK/KUP/KT Transporter Gene Families in Grape (Vitis vinifera L.)

Potassium(K+)is an essential macronutrient for plants to maintain normal growth and development.Shaker-like K+channels and HAK/KUP/KT transporters are critical components in the K+acquisition and translocation.In this study,we identified 9 Shaker-like K+channel(VvK)and 18 HAK/KUP/KT transporter(VvKUP)genes in grape,which were renamed according to their distributions in the genome and relative linear orders among the distinct chromosomes.Similar structure organizations were found within each group according to the exon/intron structure and protein motif analysis.Chromosomal distribution analysis showed that 9 VvK genes and 18 VvKUP genes were unevenly distributed on 7 or 10 putative grape chromosomes.Three pairs of tandem duplicated genes and one pair of segmental duplicated genes were observed in the expansion of the grape VvKUP genes.Gene expression omnibus(GEO)data analysis showed that VvK and VvKUP genes were expressed differentially in distinct tissues.Various cis-acting regulatory elements pertinent to phytohormone responses and abiotic stresses,including K+deficiency response and drought stress,were detected in the promoter region of VvK and VvKUP genes.This study provides valuable information for further functional studies of VvK and VvKUP genes,and lays a foundation to explore K+uptake and utilization in fruit trees.

Genome-wide identification and expression analysis of the β-amylase genes strongly associated with fruit development,ripening, and abiotic stress response in two banana cultivars

β-amylase(BAM) is an important enzyme involved in conversion of starch to maltose in multiple biological processes in plants. However, there is currently insufficient information on the BAM gene family in the important fruit crop banana. This study identified 16 BAM genes in the banana genome. Phylogenetic analysis showed that Ma BAMs were classified into four subfamilies. Most Ma BAMs in each subfamily shared similar gene structures. Conserved motif analysis showed that all identified Ma BAM proteins had the typical glyco hydro14 domains. Comprehensive transcriptomic analysis of two banana genotypes revealed the expression patterns of Ma BAMs in different tissues, at various stages of fruit development and ripening, and in responses to abiotic stresses. Most Ma BAMs showed strong transcript accumulation changes during fruit development and late-stage ripening. Some Ma BAMs showed significant changes under cold, salt, and osmotic stresses. This finding indicated that Ma BAMs might be involved in regulating fruit development, ripening, and responses to abiotic stress. Analysis of five hormone-related and seven stressrelevant elements in the promoters of Ma BAMs further revealed that BAMs participated in various biological processes. This systemic analysis provides new insights into the transcriptional characteristics of the BAM genes in banana and may serve as a basis for further functional studies of such genes.

Advancing healthcare through laboratory on a chip technology:Transforming microorganism identification and diagnostics

In a recent case report in the World Journal of Clinical Cases,emphasized the crucial role of rapidly and accurately identifying pathogens to optimize patient treatment outcomes.Laboratory-on-a-chip(LOC)technology has emerged as a transformative tool in health care,offering rapid,sensitive,and specific identification of microorganisms.This editorial provides a comprehensive overview of LOC technology,highlighting its principles,advantages,applications,challenges,and future directions.Success studies from the field have demonstrated the practical benefits of LOC devices in clinical diagnostics,epidemiology,and food safety.Comparative studies have underscored the superiority of LOC technology over traditional methods,showcasing improvements in speed,accuracy,and portability.The future integration of LOC with biosensors,artificial intelligence,and data analytics promises further innovation and expansion.This call to action emphasizes the importance of continued research,investment,and adoption to realize the full potential of LOC technology in improving healthcare outcomes worldwide.

Genome-wide identification and characterization of thaumatin-like protein family genes in wheat and analysis of their responses to Fusarium head blight infection

Thaumatin-like proteins (TLPs) play potential roles in plant resistance to various diseases. Identifying TLPs is neces-sary to determine their function and apply them to plant disease resistance. However, limited information is available about TLP-family genes in wheat, especially regarding their responses to Fusarium species, which cause Fusarium head blight in wheat. In this study, we conducted a comprehensive genome-wide survey of TLP genes in wheat and identified 129 TLP genes in the wheat genome, which were unevenly distributed on 21 wheat chromosomes, with 5A containing the highest number. Phylogenetic analysis showed that these 129 wheat TLP genes together with 24 Arabidopsis TLPs were classified into 7 groups based on the protein sequences. We systematically analyzed the genes in terms of their sequence characterization, chromosomal locations, exon-intron distribution, duplication (tandem and segmental) events and expression profiles in response to Fusarium infection. Furthermore, we analyzed differen-tially expressed TLP genes based on publicly available RNA-seq data obtained from a resistant near isogenic wheat line at different time points after Fusarium graminearum inoculation. Then, the expression of 9 differentially expressed TLP genes was confirmed by real-time PCR, and these 9 genes were all upregulated in the resistant Sumai 3 variety, which was generally consistent with the RNA-seq data. Our results provide a basis for selecting candidate wheat TLP genes for further studies to determine the biological functions of the TLP genes in wheat.

Genome-wide and candidate gene association studies identify BnPAP17 as conferring the utilization of organic phosphorus in oilseed rape

Phosphorus(P)is essential for living plants,and P deficiency is one of the key factors limiting the yield in rapeseed production worldwide.As the most important organ for plants,root morphology traits(RMTs)play a key role in P absorption.To investigate the genetic variability of RMT under low P availability,we dissected the genetic structure of RMTs by genome-wide association studies(GWAS),linkage mapping and candidate gene association studies(CGAS).A total of 52 suggestive loci were associated with RMTs under P stress conditions in 405 oilseed rape accessions.The purple acid phosphatase gene BnPAP17 was found to control the lateral root number(LRN)and root dry weight(RDW)under low P stress.The expression of BnPAP17 was increased in shoot tissue in P-efficient cultivars compared to root tissue and P-inefficient cultivars in response to low P stress.Moreover,the haplotype of BnPAP17^(Hap3)was detected for the selective breeding of P efficiency in oilseed rape.Over-expression of the BnPAP17^(Hap3)could promote the shoot and root growth with enhanced tolerance to low P stress and organic phosphorus(Po)utilization in oilseed rape.Collectively,these findings increase our understanding of the mechanisms underlying BnPAP17-mediated low P stress tolerance in oilseed rape.

Genome-wide identification and characterization of odorant-binding protein （OBP） genes in the malaria vector Anopheles sinensis （Diptera： Culicidae）

Anopheles sinensis is a major malaria vector. Insect odorant-binding proteins （OBPs） may function in the reception of odorants in the olfactory system. The classification and characterization of the An. sinensis OBP genes have not been systematically studied. In this study, 64 putative OBP genes were identified at the whole-genome level of An. sinensis based on the comparison between OBP conserved motifs, PBP_GOBE and phylogenetic analysis with An. gambiae OBPs. The characterization of An. sinensis OBPs, including the motifs conservation, gene structure, genomic organization and classification, were investigated. A new gene, AsOBP73, belonging to the Plus-C subfamily, was identified with the support of transcript and conservative motifs. These An. sinensis OBP genes were classified into three subfamilies with 37, 15 and 12 genes in the subfamily Classic, Atypical and Plus-C, respectively. The genomic organization of An. sinensis OBPs suggests a clustered distribution across nine different scaffolds. Eight genes （0BP23-28, 0BP63- 64） might originate from a single gene through a series of historic duplication events at least before divergence of Anopheles, Culex and Aedes. The microsynteny analyses indicate a very high synteny between An. sinensis and An. gambiae OBPs. OBP70 and OBP71 earlier classified under Plus-C in An. gambiae are recognized as belonging to the group Obp59a of the Classic subfamily, and OBP69 earlier classified under Plus-C has been moved to the Atypical subfamily in this study. The study established a basic information frame for further study of the OBP genes in insects as well as in An. sinensis.

Identification of commercial cultivars of Agaricus bisporus in China using genome-wide microsatellite markers

Agaricus bisporus is one of the most widely cultivated mushrooms in the world. Commercial cultivars are usually phenotypically alike and easy to be copied by isolating tissue cultures. This brings great challenges to distinguish different cultivars and to protect new varieties. Thus, techniques for the accurate identification of cultivars are essentially required. In this study, we accurately identified 11 commercial cultivars of A. bisporus released in China by using microsatellite(SSR, simple sequence repeat) markers. SSR markers were developed by mining the genome sequence. A total of 3 134 SSRs were identified, of which 1 490 SSRs were distributed in gene models, and 1 644 in the intergenic regions. A total of 17 polymorphic primer pairs were developed and SSR fingerprints were constructed for all the commercial cultivars. These SSR markers generated a total of 73 alleles, with an average of 4.29 per locus. Specifically, the primer combination of AB_SSR_2341 and AB_SSR_2590 could distinguish all the 11 commercial cultivars. The similarity coefficients of the 11 commercial cultivars were between 0.56 and 0.95 indicating that some of them were close related. Our results provide an efficient technique for the identification of A. bisporus cultivars in China, which can also facilitate the marker-assisted breeding in the future.

Identification of New Resistance Loci Against Sheath Blight Disease in Rice Through Genome-Wide Association Study

Sheath blight(SB) caused by the soil borne pathogen Rhizoctonia solani is one of the most serious global rice diseases. Breeding resistant cultivar is the most economical and effective strategy to control the disease. However, no rice varieties are completely resistant to SB, and only a few reliable quantitative trait loci(QTLs) linked with SB resistance have been identified to date. In this study, we conducted a genome-wide association study(GWAS) of SB resistance using 299 varieties from the rice diversity panel 1(RDP1) that were genotyped using 44 000 high-density single nucleotide polymorphism(SNP) markers. Through artificial inoculation, we found that only 36.5% of the tested varieties displayed resistance or moderate resistance to SB. In particular, the aromatic and aus sub-populations displayed higher SB resistance than the tropical japonica(TRJ), indica and temperate japonica sub-populations. Seven varieties showed similar resistance levels to the resistant control YSBR1. GWAS identified at least 11 SNP loci significantly associated with SB resistance in the three independent trials, leading to the identification of two reliable QTLs, qSB-3 and qSB-6, on chromosomes 3 and 6. Using favorable alleles or haplotypes of significantly associated SNP loci, we estimated that both QTLs had obvious effects on reducing SB disease severity and can be used for enhancing SB resistance, especially in improving SB resistance of TRJ sub-population rice varieties. These results provided important information and genetic materials for developing SB resistant varieties through breeding.

Identification of powdery mildew resistance loci in wheat by integrating genome-wide association study(GWAS) and linkage mapping

Wheat powdery mildew(Blumeria graminis f.sp.tritici, Bgt) is a disease of increasing importance globally due to the adoption of high yielding varieties and modern sustainable farming technologies.Growing resistant cultivars is a preferred approach to managing this disease, and novel powdery mildew resistance genes are urgently needed for new cultivar development.A genome-wide association study was performed on a panel of 1292 wheat landraces and historical cultivars using 5011 single nucleotide polymorphism(SNP)markers.The association panel was evaluated for reactions to three Bgt inoculants, OKS(14)-B-3-1, OKS(14)-C-2-1, and Bgt15.Linkage disequilibrum(LD) analysis indicated that genome-wide LD decayed to 0.1 at 23 Mb, and population structure analysis revealed seven subgroups in the panel.Association analysis using a mixed linear model(MLM) identified three loci for powdery mildew resistance on chromosome 2 B, designated QPm.stars-2BL1,QPm.stars-2BL2, and QPm.stars-2BL3.To evaluate the efficacy of GWAS in gene discovery,QPm.stars-2BL2 was validated using F2 and F2:3 populations derived from PI420646 × OK1059060-126135-3.Linkage analysis delimited the powdery mildew resistance gene in PI 420646 to an interval where QPm.stars-2BL2 was located, lending credence to the GWAS results.QPm.stars-2BL1 and QPm.stars-2BL3, which were associated with four SNPs located at 457.7–461.7 Mb and two SNPs located at 696.6–715.9 Mb in the Chinese Spring reference IWGSC RefSeq v1.0, respectively, are likely novel loci for powdery mildew resistance and can be used in wheat breeding to improve powdery mildew resistance.