MOTHER OFFT ANDTFL1regulates seed germination and fertility relevant to the brassinosteroid signaling pathway

Abstract

B rassinosteroids (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 lowfertility 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.Plant hormones exert profound effects on many fundamental processes during plant growth and development. With respect to seed development and germination, it has long been known that abscisic acid (ABA) and gibberellin (GA) are two major types of phytohormones that play antagonistic roles in regulating these events. Not until recently, another group of phytohormones, namely brassinosteroids (BRs),

Cyclin-Dependent Kinase Inhibitors KRP1 and KRP2 Are Involved in Grain Filling and Seed Germination in Rice (Oryza sativa L.)

“…In this study, we determined that KRP1 and KRP2 were preferentially induced by ABA and BR ( Figure 1C,D). Given that ABA and BR extensively regulate seed maturation and germination, as previously described [41][42][43][44][45][46], these results demonstrated that ABA and/or BR could affect the two cell cycle regulators by regulating cell proliferation during grain filling and seed germination processes.…”

Pleiotropy in developmental regulation by flowering‐pathway genes: is it an evolutionary constraint?

“…MOTHER OF FT AND TFL1 ( MFT ) is an inducer of flowering in A. thaliana and acts redundantly with FT (Yoo et al ., ). MFT is also an inducer of germination in A. thaliana , mediating GA, ABA and BR crosstalk (Xi & Yu, ; Xi et al ., ). Homologs of this gene, however, are expressed in seeds in several species, and they act primarily as a germination regulator (Nishikawa et al ., ; Q. Li et al ., ; Tao et al ., ).…”

Boosting Crop Yields with Plant Steroids

“…Exogenous BR application rescues the low germination phenotype of gibberellin mutants, and the seed germination of BR-related mutants is more sensitive to inhibition by abscisic acid (ABA) than the wild type (Steber and McCourt, 2001;Xue et al, 2009). Recent evidence suggests that the antagonistic effect of BRs on seed germination is partially mediated through the phosphatidylethanolamine binding protein MOTHER OF FT AND TFL1 (MFT) because application of BRs to loss-of-function mft mutants did not antagonize the inhibitory effect of ABA (Xi and Yu, 2010). The ABA inhibition of germination was overcome by overexpressing the Arabidopsis DWARF4 (DWF4) biosynthetic gene under the control of a seed-specific oleosin promoter in Arabidopsis .…”