title: Transgenic expression of MYB15 confers enhanced sensitivity to abscisic acid and improved drought tolerance in Arabidopsis thaliana.
abstract: Abiotic stresses cause serious crop losses. Knowledge on genes functioning in plant responses to adverse growth conditions is essential for developing stress tolerant crops. Here we report that transgenic expression of MYB15, encoding a R2R3 MYB transcription factor in Arabidopsis thaliana, conferred hypersensitivity to exogenous abscisic acid (ABA) and improved tolerance to drought and salt stresses. The promoter of MYB15 was active in not only vegetative and reproductive organs but also the guard cells of stomata. Its transcript level was substantially upregulated by ABA, drought or salt treatments. Compared with wild type (WT) control, MYB15 overexpression lines were hypersensitive to ABA in germination assays, more susceptible to ABA-elicited inhibition of root elongation, and more sensitive to ABA-induced stomatal closure. In line with the above findings, the transcript levels of ABA biosynthesis (ABA1, ABA2), signaling (ABI3), and responsive genes (AtADH1, RD22, RD29B, AtEM6) were generally higher in MYB15 overexpression seedlings than in WT controls after treatment with ABA. MYB15 overexpression lines displayed improved survival and reduced water loss rates than WT control under water deficiency conditions. These overexpression lines also displayed higher tolerance to NaCl stress. Collectively, our data suggest that overexpression of MYB15 improves drought and salt tolerance in Arabidopsis possibly by enhancing the expression levels of the genes involved in ABA biosynthesis and signaling, and those encoding the stress-protective proteins.
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Ding
authors.forename: Shiming
authors.initials: S
authors.lastname: Li
authors.forename: Xueli
authors.initials: X
authors.lastname: An
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Huanju
authors.initials: H
authors.lastname: Qin
authors.forename: Daowen
authors.initials: D
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000096:biosynthesis / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics*; D055864:Droughts; D015870:Gene Expression; D020869:Gene Expression Profiling; D017343:Genes, Plant / Q000235:genetics*; D005818:Genetic Engineering; D018525:Germination; D054046:Plant Stomata / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000378:metabolism; D012492:Salts / Q000494:pharmacology; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D019076:Transgenes / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C539643:Myb15 protein, Arabidopsis; D012333:RNA, Messenger; D012492:Salts; D014157:Transcription Factors; D000040:Abscisic Acid