胞外多肽激素基因CHAL/CLL1/CLL2在拟南芥雄蕊发育过程中发挥重要作用

Peptide hormones CHAL, CLL1, and CLL2 are important for stamen development in Arabidopsis

细胞-细胞间通讯是雄蕊正常发育过程所必需的,然而目前对于参与此过程的信号分子却鲜有报道。前期报道CHAL/CLL1/CLL2胞外多肽激素在拟南芥气孔发育过程中发挥重要作用,但是chal cll1 cll2三突变体同时表现出植株育性异常的表型。然而,这三个基因在植物雄蕊发育过程中的表达和具体功能并未见深入研究。本研究发现CHAL/CLL1/CLL2这三个基因在拟南芥花丝及5-9期花药的绒毡层和生殖细胞中高表达。同时,对三个基因功能缺失突变体的雄性育性情况进行分析后发现:单基因突变植株未表现出明显的育性异常,但双突(chal cll1和chal cll2)和三突(chal cll1 cll2)植株育性逐级下降,尤其是三突表现出一系列雄蕊异常的表型:花丝短小、花药绒毡层发育异常、部分花粉败育,且花粉萌发率亦较野生型有显著降低。进一步研究发现,chal cll1 cll2三突变体中雄蕊发育途径中关键基因BAM1、EMS1、TPD1、b HLH089、TSM1、MS1和AMS的表达水平发生显著变化。以上结果一致表明CHAL/CLL1/CLL2基因在拟南芥雄蕊发育过程中发挥重要作用。

Cell-cell communication is important for normal anther development and male fertility, but little is known about signals important for this process. The polypeptide hormones CHAL/CLL1/CLL2 are redundantly required for normal stomata cell development in Arabidopsis, but the chal cll1 cll2 triple mutants exhibited reduced fertility. However, the function of the CHAL/CLL1/CLL2 genes in the regulation of Arabidopsis fertility has not been investigated. In this study, we showed that the CHAL/CLL1/CLL2 genes were highly expressed in anther filaments, tapetal cells, and male reproductive cells at anther stage 5–9. Single mutants of the CHAL/CLL1/CLL2 genes did not show obvious fertility defects, but the double（chal cll1 and chal cll2） and triple mutants（chal cll1 cll2） showed incremental defects in fertility： short filaments, abnormal tapetal development, aborted pollens, and extremely low pollen germination rate. Further studies showed that, the expression of many anther development-required genes were obviously altered in the chal cll1 cll2 triple mutant, including BAM1, EMS1, TPD1, bHLH089, TSM1, MS1, and AMS. These data together strongly support the idea that CHAL/CLL1/CLL2 play important roles in Arabidopsis stamen development.