Liu Ye, Liu Zhihan, Li Chuang, Li Min, She Daixi, Zhang Jiahao, Ren Huiqi, Zhong Xitong, Huang Yafei, Huang Yuxiang, He Yuting, Liu Yuan, Chen Jiacai, Geng Yan, Li Xiaoli, Bo Kailiang, Weng Yiqun, Zhang Xiaolan, Zhao Jianyu
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing, 100193, China.
College of Horticulture Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, 066004, China.
J Integr Plant Biol. 2025 Jun 12. doi: 10.1111/jipb.13947.
Shoot branching is an important crop agronomic trait that directly affects plant architecture and crop productivity. Although phytochrome B (phyB), BRANCHED1 (BRC1), and abscisic acid (ABA) mediate axillary bud outgrowth, it is unknown if there is any integrating factor among them in the Plantae. We report that mutation of CsphyB or inactivation of CsphyB by shade inhibits lateral bud outgrowth in cucumber. Cucumber PHYTOCHROME INTERACTING FACTOR 4 (CsPIF4) interacts with CsphyB and directly binds to the promoter of CsBRC1 to activate CsBRC1 expression. CsBRC1 also directly promotes the expression of ABA biosynthesis gene 9-CIS-EPOXICAROTENOID DIOXIGENASE 3 (CsNCED3). Functional disruption of CsPIF4 decreased expression of CsBRC1 and CsNCED3, reduced ABA accumulation, and increased bud outgrowth in cucumber. Csnced3 mutants had reduced ABA levels and increased lateral bud outgrowth. These results suggest that a regulatory network involving CsphyB-CsPIF4-CsBRC1 exists that integrates light signaling and ABA biosynthesis to modulate bud outgrowth. This provides a strategy to manipulate branch numbers in crop breeding to realize ideal branching characteristics to maximize yield.
枝条分枝是一种重要的作物农艺性状，直接影响植株形态和作物产量。尽管光敏色素B（phyB）、BRANCHED1（BRC1）和脱落酸（ABA）介导腋芽生长，但在植物界中它们之间是否存在整合因子尚不清楚。我们报道，黄瓜中CsphyB的突变或遮荫导致的CsphyB失活会抑制侧芽生长。黄瓜光敏色素相互作用因子4（CsPIF4）与CsphyB相互作用，并直接结合到CsBRC1的启动子上以激活CsBRC1的表达。CsBRC1还直接促进脱落酸生物合成基因9-顺式环氧类胡萝卜素双加氧酶3（CsNCED3）的表达。CsPIF4的功能破坏降低了CsBRC1和CsNCED3的表达，减少了ABA积累，并增加了黄瓜中的芽生长。Csnced3突变体的ABA水平降低，侧芽生长增加。这些结果表明，存在一个涉及CsphyB-CsPIF4-CsBRC1的调控网络，该网络整合光信号和ABA生物合成以调节芽生长。这为作物育种中控制分枝数量以实现理想的分枝特性从而最大化产量提供了一种策略。
