Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, Kent Ridge, Singapore.
Plant Signal Behav. 2010 Oct;5(10):1315-7. doi: 10.4161/psb.5.10.13161. Epub 2010 Oct 1.
Brassinosteroids (BRs) are a family of plant steroid hormones that play diverse roles in many aspects of plant growth and development. For example, BRs promote seed germination by counteracting the inhibitory effect of ABA and regulate plant reproductive development, thus affecting seed yield. We have recently reported that MOTHER OF FT AND TFL1 (MFT) regulates seed germination through a negative feedback loop modulating ABA signaling in Arabidopsis. Here, we show that MFT function is also relevant to the BR signaling pathway. In mft loss-of-function mutants, the application of BR could not fully antagonize the inhibitory effect of exogenous ABA on seed germination, suggesting that BR promotes seed germination against ABA partly through MFT. In addition, mft enhances the low-fertility phenotype of det2 in which BR biosynthesis is blocked. This phenotype, together with the observation that MFT is expressed in gametophytes and developing seeds, suggests that MFT and BR play redundant roles in regulating fertility. Therefore, these results suggest that MFT affects seed germination and fertility relevant to the BR signaling pathway.
油菜素内酯（BRs）是一类植物甾体激素，在植物生长和发育的许多方面发挥着多样化的作用。例如，BRs 通过拮抗 ABA 的抑制作用促进种子萌发，并调节植物生殖发育，从而影响种子产量。我们最近报道，FT 和 TFL1 的母体蛋白（MFT）通过调节拟南芥中 ABA 信号转导，负反馈调节种子萌发。在这里，我们表明 MFT 功能也与 BR 信号通路有关。在 mft 功能丧失突变体中，BR 的应用不能完全拮抗外源 ABA 对种子萌发的抑制作用，这表明 BR 通过 MFT 促进种子萌发对抗 ABA。此外，mft 增强了 BR 生物合成受阻的 det2 低育性表型。这一表型，以及 MFT 在配子体和发育种子中表达的观察结果，表明 MFT 和 BR 在调节育性方面发挥冗余作用。因此，这些结果表明 MFT 影响与 BR 信号通路相关的种子萌发和育性。
