Advances in DNA methylation and its role in cytoplasmic male sterility in higher plants

The impact of epigenetic modifications like DNA methylation on plant phenotypes has expanded the possibilities for crop development.DNA methylation plays a part in the regulation of both the chromatin structure and gene expression,and the enzyme involved,DNA methyltransferase,executes the methylation process within the plant genome.By regulating crucial biological pathways,epigenetic changes actively contribute to the creation of the phenotype.Therefore,epigenome editing may assist in overcoming some of the drawbacks of genome editing,which can have minor off-target consequences and merely facilitate the loss of a gene’s function.These drawbacks include gene knockout,which can have such off-target effects.This review provides examples of several molecular characteristics of DNA methylation,as well as some plant physiological processes that are impacted by these epigenetic changes in the plants.We also discuss how DNA alterations might be used to improve crops and meet the demands of sustainable and environmentally-friendly farming.

Analysis of Culture Expression in the Garden Plants Disposition

Culture of the garden plants disposition was expressed in many aspects,such as the plant disposition with special cultural environment and specific environment,expression of urban culture in the plant disposition,application of plants with historical and cultural connotations in the design and protection for ancient and famous trees.

Effects of Pigment Indicators on the Color Expression of Leaves of the Colored-leaf Garden Plants

[Objective] In this study, the relationship between the pigments and the color expression of leaves of colored-leaf plants was discussed. [Method] The colors of leaf blades of 6 kinds of plants were analyzed with the Royal Horticultural Soci-ety Colour Chart. The chlorophyl content, carotenoids content and anthocyanin con-tent in leaf blades were determined. In addition, the color types of leaf blades, kinds of pigments, pigment contents and pigment distributions of 6 kinds of plants were compared. [Result] The chlorophyl contents ranked as Populus canadensis Moench （green leaves） 〉 Populus deltoids cv. Zhonghuahongye （purple green leaves） 〉 Populus euramericana cv. Quanhong （red leaves）; Acer palmatum Thunb. （green leaves） 〉 Acer palmatum cv. Atropurpureum （purple red leaves） 〉 Acer pal-matum Thunb. cv. Atropurpureum （red leaves）. The ranking of anthocyanin contents was just opposite. The chlorophyl content was negatively related to the anthocyanin content. The leaf color of plants is determined by various pigments. The more the chlorophyl is, the greener the leaf is. The more the anthocyanin is, the redder the leaf is. In the colored-leaf plants, the chlorophyl content represents about 80% of the content of pigments, the carotenoids content represents about 17%, and the an-thocyanin represents about 3%. There is a difference in the chlorophyl content be-tween colored-leaf plants and green plants. However, the relatively low chlorophyl content wil not hamper the normal life activities of colored-leaf plants. [Conclusion] We hoped to provide reference and basis for the production and landscaping of col-ored-leaf plants.

Screening of Epstein-Barr Virus Early Antigen Expression Inducers from Chinese Medicinal Herbs and Plants

Ether extrilcls of 1693 Chinesc medicinal herbs and plilnts from 268 families werestudied for the induction of Epstcin-Barr viral (EBV ) early antigcn (EA ) expression in theRaji cell line. Fifty-two from 18 families were found to have inducing activity. Twenty-fiveand seven of them were from Euphorbiaccae and Thymclaeaceae, respectively. Some ofthem, such as Croton tiglium, Euphorbia kansui, Daphnc genkwa, Wikstrocmia chamacdaphen, Wikstroemia indica, Prunus mandshurica Koehne and Achyranthes bidentata arecommonly used drugs. The significance of these herbs in the activation of EBV in vivo andtheir relation to the development of nasopharyngeal carcinoma were discussed.

Immunomodulatory effects of selected Malaysian plants on the CD18/11a expression and phagocytosis activities of leukocytes

Objective:To investigate the effects of 20 methanolic extracts from Malaysian selected plants on CD18/11 a expression and phagocytosis activity of leukocytes using flow cytometry analysis.Methods:The effects of methanolic extracts on CD18/11 a expression and phagocytosis of leukocytes were measured by labelling the cells with CD18-fluorescein isolhiocyanaie and ingestion labelled with Escherichia coli-fluorescein isothiocyanate and then analyzed using flow cytometer.Results:About 12 out of 20 methanolic extracts of selected Malaysian medicinal plants significantly(P≤0.05) inhibited the CD18/1 la expression of leukocytes at both concentrations of 6.25 μg/mL and 100 μg/mL in dose dependent manner.The most active inhibitory was shown in Citrus aurantifolia(Christm.) Swingle and Alpinia galangal(L.) Willd.at dosage 100ug/mL.Moreover,the Orthosiphon aristatus(Blume) Miq(O.aristatus).showed the highest stimulatory activity at the concentration of 100 μg/mL.Other than that,four plant extracts significantly(P<0.05) rose the phagocytosis activities of leukocytes in dose dependent manner.However,Annona muricata L.and O.aristatus showed the highest stimulated activities at the 100 pg/mL concentration.Conclusions:The results suggest that methanolic extracts of Cirrus aurantifolia.Alpinia gaiangal,O.aristatus and Annona muricata are able to modulate innate immune system and can potentially be recognized as therapeutic agents for modulating immune system.

Changes in Gene Expression in Needles and Stems of Pinus radiata Rootstock Plants of Different Ontogenic Age

A major problem in forest clonal productivity is the loss of morphogenetic capability with the increasing age of plants. However, despite of the importance of loss of morphogenetic competence, very little research has been done about the underlying mechanisms involved in this process. For this reason, a gene expression analysis using dot blot technique was performed in needles and stems of 1- and 3-year old Pinus radiata rootstock plants with a proved decrease in morphogenetic competence. Needles of one year old rootstock plants showed a higher number of up-regulated in genes mainly corresponding to photosynthesis and protein synthesis, degradation and modification, reflecting a higher number of active pathways in younger hedges, contrary to the older ones. Gene expression profiles found in stems are in agreement with those found in needles, indicating more active pathways in younger rootstock plants than in older ones. Several transcripts regulating transcription and translation were up-regulated in young competent tissues. Three-year-old stems presented an increase in the expression of an ethylene response factor, involved in plant organ senescence, indicating that pathways involved in senescence and ageing might inhibit the adventitious root formation, as in the older cuttings.

Gene Expression:A Review on Methods for the Study of Defense-Related Gene Differential Expression in Plants

The plant genes involved in cellular signaling and metabolism have not been fully identified, while the function(s) of many of those which have are as yet incompletely characterized. Gene expression analysis allows the identification of genes and the study of their relationship with cellular processes. There are several options available for studying gene expression, including the use of cDNA and microarray libraries and techniques such as suppression subtractive hybridization (SSH), differential display (DD), RNA fingerprinting by arbitrary primed PCR (RAP), expressed sequence tags (EST), serial analysis of gene expression (SAGE), representational difference analysis (RDA), cDNA-amplified fragment length polymorphism (cDNA-AFLP) and RNA sequencing (RNA-Seq). Focusing on defense-related processes in plants, we present a brief review and examples of each of these methodologies and their advantages and limitations regarding the study of plant gene expression.

Construction of Plant Expression Vector for Recombinant Human Epidermal Growth Factor (hEGF)

ObjectiveThis study aimed to construct plant expression vector for recombinant human epidermal growth factor （hEGF） and further to provide a basis for the expression of hEGF in peanut hairy root system. MethodAccording to the hEGF sequence in GenBank, hEGF was synthesized artificially; subsequently, hEGF gene was ligated with green fluorescent protein （GFP） gene, and their ligation product was then amplified with primers flanked with corresponding endonuclease cleavage sites, followed by double digestion by Sal I and EcoR I of the amplified products; next, pRI 101 AN DNA was extracted and digested by both Sal I and EcoR I; susequently, the digestion products of hEGF and GFP ligation fragment by Sal I and EcoR I and the digestion products of pRI 101 AN plasmid DNA by Sal I and EcoR I were ligated, and their ligation product was transformed into Escherichia coli XL10-Gold, followed by extraction of DNA from the recombinants exhibiting green fluorescence, which was then identified by enzymatic digestion and PCR, and the verified recombinant plasmid DNA was named pBZG101. ResultHuman epidermal growth factor gene （hEGF） and green fluorescent protein gene （GFP） were successfully ligated, and their ligation fragment was successfully ligated to pRI 101 AN DNA, finally with the acquirement of the plant expression vector for recombinant human epidermal growth factor-（pBZG101）. ConclusionThe plant expression vector for recombinant human epidermal growth factor-（pBZG101）- was successfully constructed in this study.

Construction of Plant Virus Expression Vector pClYVV/CP/W and Expression of GFP

[ Objective] The study was to report the construction of plant virus expression vector pCIYVV/CP/W and the expression of green fluorescent protein（GFP） with pCIYVV/CP/W, and to develop effective plat virus vector for plant bioreactor to produce useful protein. [ Method] A section of multiple cloning sites among NIb/CP genes in pCIYVV genome and deoxyribonucleotide polylinker of cleavage recognition sequence containing viral protease Nla were cloned with infectivity full-length cDNA of clover yellow vein virus （CIYVV）, and pCIYVV/CP/W vector was constructed, GFP gene was inserted into pCIyVV/CP/W to construct the pCIYVV/CP/W/GFP vector. The transcription situation of recombinant virus clone was detected by RT-PCR, and targeted gene products expressed by recombinant virus clone were detected with western blot （WB）. [Result] The broad bean seedling inoculated with pCIYVV/CP/W/GFP expressed the same symptom as wild type CIYVV, morbidity was of 100%, the result showed that recombinant virus clone pCIYVV/CP/W/GFP didn＇t suppress, insertion of foreign gene didn＇t destroy the open reading frame of pCIYVV/CP/W. Foreign gene can keep living in F, progeny virus genorne steadily, recombinant virus clone pCIYVV/CP/W/GFP could steadily express GFP in progeny virus at least.[ Conclusion] The useful plant virus vector was provided for useful protein expressing.

Cloning of H6H Gene from Atropa belladonna and Construction of the Efficient Plant Expression Vector

[Objective] The aim was to clone H6H gene from Atropa belladonna and construct an efficient plant expression vector.[Method] The coding sequence of H6H（Hyoscyamine 6β-hydroxylase）was cloned from Atropa belladonna with RT-PCR.Then,the sequence was subcloned into the reconstructed plant binary expression vector p2301 to construct the recombinant vector p2301-H6H,which was then introduced into Agrobacterium tumefaciens strain LBA4404 and Agrobacterium rhizogenes strain C58C1,respectively.[Result] The engineering bacteria p2301-H6H-LBA4404 and p2301-H6H-C58C1 which could be directly used in genetic improvement were obtained.[Conclusion] The present research provided basis for the increasing of alkaloid content of Atropa belladonna by plant genetic engineering technology.

Cloning of CBF3 Gene from Arabidopsis thaliana and Construction of Plant Expression Vector

[Objective] The aim was to clone CBF3 gene from Arabidopsis thaliana and construct plant expression vector pCAMBIA1301-Rd29A-CBF3.[Method] CBF3 gene and stress-inducible promoter Rd29A were amplified from the genomic DNA of A.thaliana for the construction of plant expression vector.[Result] Sequencing results showed that the cloned CBF3 gene had 750 bp,and showed 100% identity with the sequence published on GenBank.The promoter Rd29A had 1 425 bp,and showed 100% identity with the sequence published on GenBank.[Conclusion] Based on the binary vector pCAMBIA1301,the plant expression vector pCAMBIA1301-Rd29A-CBF3 was constructed successfully,which could materially improve the salt resistance,drought-tolerance,cold resistance of plants.

Transient Expression of Exogenous Gene into Plant Cell Mediated by PEI Nanovector

This study was carried out to investigate the transfection effect of exogenous gene into plant protoplast cell mediated by polyethylenimine （PEI） nanovector, based on PEI gene delivery system in the field of medical science. PEI/DNA complexes were prepared by using PEI polymer to bind the plant expression plasmid, pCMl205-GFPn. The ability of PEI combining and protecting DNA was investigated by agarose gel electrophoresis retardation assay. The surface characteristics of PEI/DNA complexes were observed with transmission electron microscope. The transfection efficiency of Arabidopsis thaliana protoplasts mediated by PEI/DNA complexes at different N/P ratios was analyzed based on observation of transient expression of green fluorescent protein with confocal laser scanning microscope. PEI could bind and condense DNA, and form stable 100-200 nm PEI/DNA complexes when the proportion of PEl and DNA is in the range of 5：1-1：4. Transfection efficiency of PEI/DNA complexes increased with N/P ratios in range of N/P〈5 and reached the highest at N/P=5, and began to decrease beyond N/P〉5 as higher toxicity to cells. The transfection efficiency of PEI/DNA complexes at N/P=5 was higher than PEG. This study confirmed that PEI nanovector could effectively mediate foreign gene entering into A. thaliana protoplast cell to obtain transient expression, which may be developed as a hopeful and novel transgenic method combined with plant protoplast regeneration.

Thansgenic peanut plants obtained by particle bombardment via somatic embryogenesis regeneration system

After pre-culture and treatment of osmosis, cotyledons of immature peanut (Arachis hypogaea L.) zygotic embryos were transformed via particle bombardment with a plasmid containing a chimeric hph gene conferring resistance to hygromycin and a chimeric intron-gus gene. Selection for hygromycin resistant calluses and somatic embryos was initiated at 10th d post-bombardment on medium containing 10-25 mg/L hygromycin. Under continuous selection, hygromycin resistant plantlets were regenerated from somatic embryos and were recovered from nearly 1.6% of the bombarded cotyledons. The presence and integration of foreign DNA in regenerated hygromycin resistant plants was confirmed by PCR (polymerase chain reaction) for the intron-gus gene and by Southern hybridization of the hph gene. GUS enzyme activity was detected in leaflets from transgenic plants but not from control, non-transformed plants. The production of transgenic plants are mainly based on a newly improved somatic embryogenesis regeneration system developed by us.

Application of Real-time Fluorescent Quantitative PCR in Studies on Plants

Real-Lime fluorescent quantitative PCR is a method for quantitative analysis of gene expression developed in recent years, which has been widely used in various fields such as basic scientific research, clinical diagnosis, disease study, drug research and development since its appearance. It starts relatively late in study on plants, but has already been used for analysis of gene expression in plants and gene identification of exogenous genes. The principles or advantages and dis- advantages of real-time fluorescent quantitative PCR, or its potential problems and condition optimizations in tests were introduced in this study, and then the appli- cation and prospect of real-time fluorescent quantitative PCR in study on plants were also been discussed.

Cloning of XET gene from Anthocephalus chinensis and its plant expression vector construction

A full-length cDNA sequence of xyloglucan endotransglycosylase gene （XET）, abundantly expressed in the cambium of Anthocephalus chinensis was cloned by conserved PCR, rapid-amplification of cDNA ends and by chromosome walking. Analytical results of the DNA sequence show that a 912 bp complete open reading frame （ORF） encoded a 303-amino acid protein was in the 1205 bp full cDNA sequence. The deduced amino acid sequence of AcXET, which contained the conserved specific EIDFE catalytic site sequence to XETs was homologous to the other known XET proteins. In order to study the gene function of AcXET and obtain transgenic plants, a plant expression vector pBIAcXET was constructed by recombinating the AcXET fragment from the cloning vector pMD19AcXET and the binary vector pBI121 between the XbaI and SmaI sites. The fragment ofAcXET gene was inserted between the CaMV 35S promotor and the coding region of the GUS gene in pBI121. The identification results show that the plant expression binary vector pBIAcXET was constructed successfully. These results lay the foundation for studying the molecular mechanism ofAcXET gene during wood formation.

Cloning the Promoter of BcNA1 from Brassica napus and Fad2 Gene from Arabidopsis thaliana and Construction of the Plant Expression Vector

The upstream regulatory region of a seed specific gene was isolated from the genomic DNA of Brassica napus by PCR amplification. The cloned fragment contained 1755 nucleotides, and shared a sequence homology of 99.6% with the reported data. The coding region of oleic acid desaturase gene was then cloned from Arabidopsis thaliana. The sequencing analysis indicated that the sequence of the PCR product was just the same as reported before. In addition, the plant expression vector harboring the seed specific promoter and trans Fad2 gene was constructed.

Dietary plant extracts modulate gene expression profiles in alveolar macrophages of pigs experimentally infected with porcine reproductive and respiratory syndrome virus

Background: Our previous study showed that 3 plant extracts enhanced the immune responses and growth efficiency of weaned pigs infected with porcine reproductive and respiratory syndrome virus(PRRSV), which is one of the most economically important disease in swine industry. However, each plant extract differently effected on growth efficiency and immune responses. Therefore, the objective of this study was conducted to characterize the effects and investigate the potential underlying mechanisms of 3 plant extracts on gene expression of alveolar macrophages in weaned pigs experimentally infected with PRRSV.Results: PRRSV infection altered(P < 0.05) the expression of 1,352 genes in pigs fed the control(CON;755 up, 597 down). Compared with the infected CON, feeding capsicum(CAP), garlic botanical(GAR), or turmeric oleoresin(TUR) altered the expression of 46 genes(24 up, 22 down), 134 genes(59 up, 75 down), or 98 genes(55 up, 43 down) in alveolar macrophages of PRRSV-infected pigs, respectively. PRRSV infection up-regulated(P < 0.05) the expression of genes related to cell apoptosis, immune system process, and response to stimulus, but downregulated(P < 0.05) the expression of genes involved in signaling transduction and innate immune response.Compared with the infected CON, feeding TUR or GAR reduced(P < 0.05) the expression of genes associated with antigen processing and presentation, feeding CAP up-regulated(P < 0.05) the expression of genes involved in antigen processing and presentation. Supplementation of CAP, GAR, or TUR also enhanced(P < 0.05) the expression of several genes related to amino acid metabolism, steroid hormone synthesis, or RNA degradation, respectively.Conclusions: The results suggest that 3 plant extracts differently regulated the expression of genes in alveolar macrophages of PRRSV-infected pigs, especially altering genes involved in immunity.

Plant Antifreeze Proteins and Their Expression Regulatory Mechanism

Low temperature is one of the major limiting environmental factors which constitutes the growth, development, productivity and distribution of plants. Over the past several years, the proteins and genes associated with freezing resistance of plants have been widely studied. The recent progress of domestic and foreign research on plant antifreeze proteins and the identifica- tion and characterization of plant antifreeze protein genes, especially on expression regulatory mechanism of plant antifreeze proteins are reviewed in this paper. Finally, some unsolved problems and the trend of research in physiological functions and gene expression regulatory mechanism of plant antifreeze proteins are discussed.

Novel expressed sequence tags of an alpine-cold plant species,Gymnadenia conopsea (Orchidaceae)

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.

Construction of Plant Expression Vector of Heat Shock Factor Gene AtHsfA1a from Arabidopsis

[ Objective ] Heat shock factors （HSFs） are the major transcription factors of eukaryotic heat shock responses. This study aims to investigate the adversity stress tolerance functions of Arabidopsis heat shock factor AtHsfAla, which has important significance for in-depth understanding of adversity stress tolerance mechanisms of plants and further utilization of heat shock factor genes. [Method] Genomic DNA of Arabidopsis was extracted with CTAB method and purified to obtain Arabidopsis DNA samples for in vitro site-specific recombination cloning （ Gateway cloning） to construct plant expression vector of heat shock factor AtHs- fAla. Firstly, donor vector pDONR 201/AtHsfAla was constructed based on attB and attP site-specific recombination method （BP reaction）, to identify E. coli transformants harboring correct sequence of AtHsfAla by sequencing; secondly, plant expression vector pBTWG2/AttlsfAla overexpressing Arabidopsis heat shock factor AtHsfAla was constructed based on attL and attR site-specific recombination method （LR reaction）, to screen E. coli transformants harboring target plasmid. [ Result] Plant expression vector of Arabidopsis heat shock factor gene AtHsfAla was constructed successfully. [ Conclusion] This study not only provided experimental materials for acquiring transgenic plants overexpressing heat shock transcription factor AtHsfAla, but also laid the foundation for further investigation of the diversity of adversity stress tolerance functions reanlated by HSFs.