Institute of Biochemistry and Biology, University of Potsdam, Karl Liebknecht Straße 24-25, Haus 20, 14476, Potsdam, Germany; Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Germany.
Plant J. 2013 Oct;76(2):258-73. doi: 10.1111/tpj.12286. Epub 2013 Aug 26.
Growth regulation is an important aspect of plant adaptation during environmental perturbations. Here, the role of MULTIPASS (OsMPS), an R2R3-type MYB transcription factor of rice, was explored. OsMPS is induced by salt stress and expressed in vegetative and reproductive tissues. Over-expression of OsMPS reduces growth under non-stress conditions, while knockdown plants display increased biomass. OsMPS expression is induced by abscisic acid and cytokinin, but is repressed by auxin, gibberellin and brassinolide. Growth retardation caused by OsMPS over-expression is partially restored by auxin application. Expression profiling revealed that OsMPS negatively regulates the expression of EXPANSIN (EXP) and cell-wall biosynthesis as well as phytohormone signaling genes. Furthermore, the expression of OsMPS-dependent genes is regulated by auxin, cytokinin and abscisic acid. Moreover, we show that OsMPS is a direct upstream regulator of OsEXPA4, OsEXPA8, OsEXPB2, OsEXPB3, OsEXPB6 and the endoglucanase genes OsGLU5 and OsGLU14. The multiple responses of OsMPS and its target genes to various hormones suggest an integrative function of OsMPS in the cross-talk between phytohormones and the environment to regulate adaptive growth.
生长调控是植物在环境胁迫下适应的一个重要方面。在这里，我们探讨了水稻 R2R3 型 MYB 转录因子 MULTIPASS（OsMPS）的作用。盐胁迫诱导 OsMPS 的表达，并在营养和生殖组织中表达。过表达 OsMPS 会在非胁迫条件下降低生长，而敲低植物则表现出生物量增加。ABA 和细胞分裂素诱导 OsMPS 的表达，而生长素、赤霉素和油菜素内酯则抑制其表达。生长素的应用部分恢复了 OsMPS 过表达引起的生长迟缓。表达谱分析显示，OsMPS 负调控 EXPANSIN（EXP）和细胞壁生物合成以及植物激素信号转导基因的表达。此外，OsMPS 依赖基因的表达受生长素、细胞分裂素和脱落酸的调节。此外，我们还表明，OsMPS 是 OsEXPA4、OsEXPA8、OsEXPB2、OsEXPB3、OsEXPB6 和内切葡聚糖酶基因 OsGLU5 和 OsGLU14 的直接上游调节剂。OsMPS 及其靶基因对各种激素的多重反应表明，OsMPS 在植物激素与环境之间的交叉对话中具有整合功能，以调节适应性生长。
