The control of axillary meristem fate in the maize ramosa pathway
The control of axillary meristem fate in the maize ramosa pathway
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DOI：
10.1242/dev.051748
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发表时间：
2010-09-01
期刊：
影响因子：
4.6
通讯作者：
Schmidt, Robert J.
中科院分区：
文献类型：
--
作者：
Gallavotti, Andrea;Long, Jeff A.;Schmidt, Robert J.
植物腋生分生组织由高度组织化、自我更新的干细胞组成，这些干细胞产生不确定的分支或终止于分化的结构，如花。这些由遗传和环境因素决定的相反的命运决定了植物结构的种间差异。Cys(2)-His(2)锌指转录因子RAMOSA1 （RA1）在玉米花序、穗和穗的早期发育过程中调控大多数腋生分生组织的命运，并与草结构的进化有关。RA1或RAMOSA2和RAMOSA3这两个已知的ramosa通路成员的突变会产生高度分枝的花序。在这里，我们报道了玉米花序分枝增强的遗传筛选，并发现了一个新的分生组织命运调节因子：RAMOSA1 ENHANCER LOCUS2 （REL2）基因。Rel2突变体显著增加了ra1和ra2突变体耳长分枝的形成。REL2编码一个类似于拟南芥toppless蛋白的转录共抑制因子，已知在胚胎发生过程中维持顶基极性。REL2能够挽救拟南芥toplless -1突变体的胚胎缺陷，这表明REL2在整个发育过程中也作为转录共抑制因子发挥作用。我们通过遗传和分子分析表明，REL2与RA1相互作用，表明REL2/RA1转录抑制复合物在玉米花序发育过程中拮抗不确定分枝的形成。我们的研究结果揭示了一种控制分生组织命运和植物结构的新机制。
Plant axillary meristems are composed of highly organized, self-renewing stem cells that produce indeterminate branches or terminate in differentiated structures, such as the flowers. These opposite fates, dictated by both genetic and environmental factors, determine interspecific differences in the architecture of plants. The Cys(2)-His(2)zinc-finger transcription factor RAMOSA1 (RA1) regulates the fate of most axillary meristems during the early development of maize inflorescences, the tassel and the ear, and has been implicated in the evolution of grass architecture. Mutations in RA1 or any other known members of the ramosa pathway, RAMOSA2 and RAMOSA3, generate highly branched inflorescences. Here, we report a genetic screen for the enhancement of maize inflorescence branching and the discovery of a new regulator of meristem fate: the RAMOSA1 ENHANCER LOCUS2 (REL2) gene. rel2 mutants dramatically increase the formation of long branches in ears of both ra1 and ra2 mutants. REL2 encodes a transcriptional co-repressor similar to the TOPLESS protein of Arabidopsis, which is known to maintain apical-basal polarity during embryogenesis. REL2 is capable of rescuing the embryonic defects of the Arabidopsis topless-1 mutant, suggesting that REL2 also functions as a transcriptional co-repressor throughout development. We show by genetic and molecular analyses that REL2 physically interacts with RA1, indicating that the REL2/RA1 transcriptional repressor complex antagonizes the formation of indeterminate branches during maize inflorescence development. Our results reveal a novel mechanism for the control of meristem fate and the architecture of plants.