Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr, 3 OT Gatersleben, D-06466, Seeland, Germany.
Technical University of Munich and Helmholtz Center Munich, Institute of Environmental Medicine, UNIKA-T, Neusäßer Str. 47, 86156, Augsburg, Germany.
Nat Commun. 2020 Oct 12;11(1):5138. doi: 10.1038/s41467-020-18890-y.
Grasses have varying inflorescence shapes; however, little is known about the genetic mechanisms specifying such shapes among tribes. Here, we identify the grass-specific TCP transcription factor COMPOSITUM 1 (COM1) expressing in inflorescence meristematic boundaries of different grasses. COM1 specifies branch-inhibition in barley (Triticeae) versus branch-formation in non-Triticeae grasses. Analyses of cell size, cell walls and transcripts reveal barley COM1 regulates cell growth, thereby affecting cell wall properties and signaling specifically in meristematic boundaries to establish identity of adjacent meristems. COM1 acts upstream of the boundary gene Liguleless1 and confers meristem identity partially independent of the COM2 pathway. Furthermore, COM1 is subject to purifying natural selection, thereby contributing to specification of the spike inflorescence shape. This meristem identity pathway has conceptual implications for both inflorescence evolution and molecular breeding in Triticeae.
禾本科植物的花序形状各异;然而,关于指定这些形状的遗传机制在族间的研究还很少。在这里,我们鉴定了在不同禾本科植物的花序分生组织边界表达的禾本科特异性 TCP 转录因子 COMPOSITUM 1(COM1)。COM1 在大麦(禾本科)中指定分支抑制,而在非禾本科禾本科植物中指定分支形成。对细胞大小、细胞壁和转录本的分析表明,大麦 COM1 调节细胞生长,从而影响分生组织边界的细胞壁特性和信号转导,以确定相邻分生组织的身份。COM1 在前缘基因 Liguleless1 的上游起作用,并部分独立于 COM2 途径赋予分生组织身份。此外,COM1 受到纯化自然选择的影响,从而有助于指定穗状花序的形状。这个分生组织身份途径对禾本科植物的花序进化和分子育种具有概念上的意义。