Department of Plant Sciences, University of California, Davis, CA 95616, USA.
Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
Development. 2019 Jul 23;146(14):dev175398. doi: 10.1242/dev.175398.
The spikelet is the basic unit of the grass inflorescence. In this study, we show that wheat MADS-box genes , and play critical and redundant roles in spikelet and spike development, and also affect flowering time and plant height. In the -null triple mutant, the inflorescence meristem formed a normal double-ridge structure, but then the lateral meristems generated vegetative tillers subtended by leaves instead of spikelets. These results suggest an essential role of these three genes in the fate of the upper spikelet ridge and the suppression of the lower leaf ridge. Inflorescence meristems of -null and -null remained indeterminate and single -null and null mutants showed delayed formation of the terminal spikelet and increased number of spikelets per spike. Moreover, the -null mutant showed more florets per spikelet, which together with a higher number of spikelets, resulted in a significant increase in the number of grains per spike in the field. Our results suggest that a better understanding of the mechanisms underlying wheat spikelet and spike development can inform future strategies to improve grain yield in wheat.
小穗是禾本科植物花序的基本单位。本研究表明，小麦 MADS -box 基因、和在小穗和穗发育中起关键和冗余作用，同时也影响开花时间和株高。在 -null 三突变体中，花序分生组织形成正常的双脊结构，但随后侧生分生组织产生由叶片下延的营养分蘖，而不是小穗。这些结果表明这三个基因在顶部小穗脊的命运和下部叶片脊的抑制中起重要作用。-null 和 -null 的花序分生组织仍然不定，-null 和 -null 单突变体表现出终端小穗形成延迟，每穗小穗数增加。此外，-null 突变体表现出每个小穗的小花数增加，加上小穗数的增加，导致田间每穗粒数显著增加。我们的结果表明，更好地理解小麦小穗和穗发育的机制可以为未来提高小麦产量的策略提供信息。
