UNBRANCHED3 regulates branching by modulating cytokinin biosynthesis and signaling in maize and rice
UNBRANCHED3 regulates branching by modulating cytokinin biosynthesis and signaling in maize and rice
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UNBRANCHED3 通过调节玉米和水稻的细胞分裂素生物合成和信号传导来调节分枝
DOI：
10.1111/nph.14391
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发表时间：
2017-04-01
期刊：
影响因子：
9.4
通讯作者：
Zhang, Zuxin
中科院分区：
文献类型：
--
作者：
Du, Yanfang;Liu, Lei;Zhang, Zuxin
UNBRANCHED 3（UB 3）是SQUAMOSA启动子结合蛋白样（SPL）基因家族的成员，通过负调节玉米花序分生组织的大小来调节玉米籽粒行数。然而，UB 3介导分枝的调控途径尚不清楚，我们将UB 3分别导入水稻和玉米中，以揭示其在这两种作物中的作用。通过转录组测序和蛋白质-DNA结合分析，我们发现UB 3可以结合并调控LONELY GUY 1（LOG 1）和A型反应调节因子（ARRs）的启动子，这两个因子参与细胞分裂素的生物合成和信号转导。过量表达外源UB 3的水稻（Oryza sativa）显着抑制分蘖和穗分枝的活性细胞分裂素的量更大的减少的结果。与此相反，UB 3的适度表达对分蘖有一定的抑制作用，但与SPL基因协同作用促进了穗分枝，从而提高了水稻的穗粒数。在玉米（Zea mays）ub 3突变体中，与细胞分裂素生物合成相关的基因表达上调，而与降解相关的基因表达下调，表明UB 3通过调节细胞分裂素的生物合成和信号传导来调控玉米和水稻的营养分枝和生殖分枝。
UNBRANCHED3 (UB3), a member of the SQUAMOSA promoter binding protein-like (SPL) gene family, regulates kernel row number by negatively modulating the size of the inflorescence meristem in maize. However, the regulatory pathway by which UB3 mediates branching remains unknown.We introduced the UB3 into rice and maize to reveal its effects in the two crop plants, respectively. Furthermore, we performed transcriptome sequencing and protein-DNA binding assay to elucidate the regulatory pathway of UB3.We found that UB3 could bind and regulate the promoters of LONELY GUY1 (LOG1) and Type-A response regulators (ARRs), which participate in cytokinin biosynthesis and signaling. Overexpression of exogenous UB3 in rice (Oryza sativa) dramatically suppressed tillering and panicle branching as a result of a greater decrease in the amount of active cytokinin. By contrast, moderate expression of UB3 suppressed tillering slightly, but promoted panicle branching by cooperating with SPL genes, resulting in a higher grain number per panicle in rice. In maize (Zea mays) ub3 mutant with an increased kernel row number, UB3 showed a low expression but cytokinin biosynthesis-related genes were up-regulated and degradation-related genes were down-regulated.These results suggest that UB3 regulates vegetative and reproductive branching by modulating cytokinin biosynthesis and signaling in maize and rice.