MYB家族转录因子OsMYB84通过ABA信号通路参与盐胁迫响应

The MYB Family Transcription Factor OsMYB84 Confers Salt Stress Response Through the ABA Pathway

MYB家族是植物中最大的转录因子家族之一,功能广泛,这类蛋白在植物器官形态建成、次生代谢、激素代谢和信号途径起关键调控作用.从水稻中克隆R2R3-MYB家族转录因子OsMYB84,聚类分析结果表明OsMYB84为拟南芥MYB84同源基因,洋葱表皮亚细胞定位研究显示OsMYB84为核定位蛋白.器官表达谱和原位杂交分析实验显示OsMYB84在水稻叶枕、茎以及根中高表达.构建OsMYB84过表达体系,筛选出纯合株系.与野生型相比,OsMYB84转基因水稻的株高明显矮化,因此推测OsMYB84可能通过影响茎和叶枕处侧生分生组织进而改变株高.另一方面,激素和胁迫表达谱分析结果表明,OsMYB84受到ABA、高盐的显著诱导.同时,OsMYB84显著提高了转基因水稻的耐盐特性,减少细胞损伤并且也提高了转基因水稻种子对ABA的敏感性,这暗示着OsMYB84基因可能通过依赖ABA信号通路参与水稻盐胁迫应答反应.

MYB family is one of the biggest transcription factors in plant with various functions.This type of genes plays a key regulatory role in organ morphogenesis,secondary plant growth,hormone metabolism and signaling pathways.OsMYB84,a member of R2R3-MYB transcription factors,was cloned from rice（Oryza sativa L.）.Phylogenetic analysis showed that OsMYB84 was a homologous gene of MYB84 in Arabidopsis thaliana.The OsMYB84-GFP fusion protein was localized to the nucleus in a transient expression assay.Expression pattern in organs and in situ hybridization analysis results showed that OsMYB84 was highly expressed in pulvini,stem and root in rice.In this study,we constructed OsMYB84 over-expression system,and identified homozygous transgenic lines.Compared with the wild type,the height of the transgenic lines was lower significantly,thus OsMYB84 might alter the plant height through the lateral meristem in stem and pulvini.Otherwise,expression pattern of hormones and abiotic stress showed that OsMYB84 was highly induced by ABA and high salinity.Meanwhile,transgenic lines of OsMYB84 were conferred enhanced tolerance to high salinity and reduced damage of cells and the seeds of transgenic lines also improved the sensitivity to abscisic acid,compared with wild type rice.Our data suggest that OsMYB84 plays a role in mediating salt stress responses through the ABA pathway in rice.