Interaction of brassinosteroid and cytokinin promotes ovule initiation and increases seed number per silique in Arabidopsis
Interaction of brassinosteroid and cytokinin promotes ovule initiation and increases seed number per silique in Arabidopsis
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油菜素类固醇和细胞分裂素的相互作用促进拟南芥中胚珠的形成并增加每角果的种子数量
DOI：
10.1111/jipb.13197
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发表时间：
2022-03-01
影响因子：
11.4
通讯作者：
Lin，Wen-Hui
中科院分区：
文献类型：
--
作者：
Zu，Song-Hao;Jiang，Yu-Tong;Lin，Wen-Hui
胚珠发生是影响胚珠数量和种子产量的关键步骤。值得注意的是，与野生型植物相比，具有增强的油菜素类固醇（BR）和细胞分裂素（CK）信号传导的突变体产生更多的胚珠并且具有更高的每角果种子数（SNS）。在这里，我们将BR和CK相关突变体杂交，以测试这些植物激素是否在胚珠启动中一起起作用。同时提高BR和CK含量比单独提高BR或CK含量能增加胚珠数和种子数，且BR和CK是相互促进的。此外，BR-反应转录因子BZR 1直接与CK-反应转录因子拟南芥反应调节因子1（ARR 1）相互作用。BR或BR + CK处理加强了这种相互作用，随后ARR 1靶向和诱导下游基因，以促进胚珠启动。增强的CK信号转导部分地挽救了BR缺失/不敏感突变体的降低的SNS表型，而增强的BR信号转导未能挽救CK缺失突变体的低SNS，这表明BR通过CK介导的和非依赖的途径调节胚珠起始和SNS。因此，BR和CK互作促进胚珠发生，增加种子数量，为提高双子叶作物种子产量提供了重要线索。
Ovule initiation is a key step that strongly influences ovule number and seed yield. Notably, mutants with enhanced brassinosteroid (BR) and cytokinin (CK) signaling produce more ovules and have a higher seed number per silique (SNS) than wild‐type plants. Here, we crossed BR‐ and CK‐related mutants to test whether these phytohormones function together in ovule initiation. We determined that simultaneously enhancing BR and CK contents led to higher ovule and seed numbers than enhancing BR or CK separately, and BR and CK enhanced each other. Further, the BR‐response transcription factor BZR1 directly interacted with the CK‐response transcription factor ARABIDOPSIS RESPONSE REGULATOR1 (ARR1). Treatments with BR or BR plus CK strengthened this interaction and subsequent ARR1 targeting and induction of downstream genes to promote ovule initiation. Enhanced CK signaling partially rescued the reduced SNS phenotype of BR‐deficient/insensitive mutants whereas enhanced BR signaling failed to rescue the low SNS of CK‐deficient mutants, suggesting that BR regulates ovule initiation and SNS through CK‐mediated and ‐independent pathways. Our study thus reveals that interaction between BR and CK promotes ovule initiation and increases seed number, providing important clues for increasing the seed yield of dicot crops.