花粉管
油菜素甾醇
花粉
扩张素
生物
细胞生物学
油菜素内酯
梨
核糖核酸酶P
泛素连接酶
植物
泛素
生物化学
拟南芥
授粉
核糖核酸
突变体
植物生长
基因表达
基因
作者
Yicheng Wang,Panpan Liu,Yiling Cai,Yu Li,Chao Tang,Nan Zhu,Peng Wang,Shaoling Zhang,Juyou Wu
出处
期刊:Plant Physiology
[Oxford University Press]
日期:2023-04-03
卷期号:192 (3): 2356-2373
被引量:6
标识
DOI:10.1093/plphys/kiad208
摘要
Abstract S-RNase-mediated self-incompatibility (SI) prevents self-fertilization and promotes outbreeding to ensure genetic diversity in many flowering plants, including pear (Pyrus sp.). Brassinosteroids (BRs) have well-documented functions in cell elongation, but their molecular mechanisms in pollen tube growth, especially in the SI response, remain elusive. Here, exogenously applied brassinolide (BL), an active BR, countered incompatible pollen tube growth inhibition during the SI response in pear. Antisense repression of BRASSINAZOLE-RESISTANT1 (PbrBZR1), a critical component of BR signaling, blocked the positive effect of BL on pollen tube elongation. Further analyses revealed that PbrBZR1 binds to the promoter of EXPANSIN-LIKE A3 (PbrEXLA3) to activate its expression. PbrEXLA3 encodes an expansin that promotes pollen tube elongation in pear. The stability of dephosphorylated PbrBZR1 was substantially reduced in incompatible pollen tubes, where it is targeted by ARIADNE2.3 (PbrARI2.3), an E3 ubiquitin ligase that is strongly expressed in pollen. Our results show that during the SI response, PbrARI2.3 accumulates and negatively regulates pollen tube growth by accelerating the degradation of PbrBZR1 via the 26S proteasome pathway. Together, our results show that an ubiquitin-mediated modification participates in BR signaling in pollen and reveal the molecular mechanism by which BRs regulate S-RNase-based SI.
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