Plant Stress and Germplasm Development Unit, Cropping Systems Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Lubbock, TX 79415, USA.
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Int J Mol Sci. 2019 Oct 8;20(19):4951. doi: 10.3390/ijms20194951.
As in other cereal crops, the panicles of sorghum ( (L.) Moench) comprise two types of floral spikelets (grass flowers). Only sessile spikelets (SSs) are capable of producing viable grains, whereas pedicellate spikelets (PSs) cease development after initiation and eventually abort. Consequently, grain number per panicle (GNP) is lower than the total number of flowers produced per panicle. The mechanism underlying this differential fertility is not well understood. To investigate this issue, we isolated a series of ethyl methane sulfonate (EMS)-induced () mutants that result in full spikelet fertility, effectively doubling GNP. Previously, we showed that MSD1 is a TCP (Teosinte branched/Cycloidea/PCF) transcription factor that regulates jasmonic acid (JA) biosynthesis, and ultimately floral sex organ development. Here, we show that encodes a lipoxygenase (LOX) that catalyzes the first committed step of JA biosynthesis. Further, we demonstrate that MSD1 binds to the promoters of and other JA pathway genes. Together, these results show that a JA-induced module regulates sorghum panicle development and spikelet fertility. The findings advance our understanding of inflorescence development and could lead to new strategies for increasing GNP and grain yield in sorghum and other cereal crops.
与其他谷类作物一样，高粱（（L.）Moench）的圆锥花序由两种类型的小花组成（草花）。只有无梗小穗（SS）才能产生有活力的籽粒，而花梗小穗（PS）在起始后停止发育，最终败育。因此，每穗粒数（GNP）低于每穗产生的花总数。这种差异育性的机制尚不清楚。为了研究这个问题，我们分离了一系列导致整穗育性完全的乙磺酸（EMS）诱导突变体，有效地使 GNP 增加了一倍。此前，我们表明 MSD1 是一个 TCP（Teosinte branched/Cycloidea/PCF）转录因子，它调节茉莉酸（JA）的生物合成，最终调节花器官的发育。在这里，我们表明 编码一个脂氧合酶（LOX），它催化 JA 生物合成的第一步。此外，我们证明 MSD1 结合到 和其他 JA 途径基因的启动子上。这些结果表明，一个 JA 诱导的模块调节高粱花序发育和小穗育性。研究结果提高了我们对花序发育的认识，并可能为提高高粱和其他谷类作物的 GNP 和粒产量提供新的策略。
