Brassinosteroids Act as a Positive Regulator of Photoprotection in Response to Chilling Stress
Brassinosteroids Act as a Positive Regulator of Photoprotection in Response to Chilling Stress
复制标题
油菜素类固醇作为响应寒冷胁迫的光保护的正调节剂
DOI：
10.1104/pp.19.00088
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发表时间：
2019-08-01
期刊：
影响因子：
7.4
通讯作者：
Yu, Jingquan
中科院分区：
文献类型：
--
作者：
Fang, Pingping;Yan, Mengyu;Yu, Jingquan
光保护是植物在逆境条件下为避免光抑制而采取的重要策略。然而，光保护的调节方式尚未完全了解。在这里，我们证明了番茄（番茄）突变体的油菜素类固醇（BR）的生物合成（dwf）和相关的信号转导通过BRASSINAZOLE-RESISTANT 1（bzr 1）是更敏感的（PSII和PSI光抑制，减少循环电子流周围PSI和较低的非光化学淬灭，积累PSII亚基S（PsbS），紫黄质脱环氧酶（VDE）的活性，和D1蛋白丰度。低温诱导了活性BR的积累和激活的BZR 1，其直接激活了质外体中的植物爆发氧化酶同源物1（RBOH 1）的转录和过氧化氢的产生。虽然质外体过氧化氢对于诱导质子梯度调节（PGR 5）依赖性循环电子流是必不可少的，但PGR 5参与调节非光化学猝灭的冷冻和BR依赖性诱导、D1、VDE和PsbS蛋白的积累、参与氧化还原信号传导的基因转录、激素信号传导和几种抗氧化酶的活性。BZR 1和PGR 5的突变或RBOH 1的转录抑制损害了低温和BR诱导的光保护，导致对光抑制的敏感性增加。这些结果表明，BRs作为一个积极的调节光保护在氧化还原-PGR 5依赖的方式在番茄低温胁迫的反应。
Photoprotection is an important strategy adopted by plants to avoid photoinhibition under stress conditions. However, the way in which photoprotection is regulated is not fully understood. Here, we demonstrate that tomato (Solanum lycopersicum) mutants of brassinosteroid (BR) biosynthesis (dwf) and related signaling through BRASSINAZOLE-RESISTANT1 (bzr1) are more sensitive to (PSII and PSI photoinhibition, with decreased cyclic electron flow around PSI and lower nonphotochemical quenching, accumulation of PSII subunit S (PsbS), violaxanthin deepoxidase (VDE) activity, and D1 protein abundance. Chilling induced the accumulation of active BRs and activated BZR1, which directly activates the transcription of RESPIRATORY BURST OXIDASE HOMOLOG1 (RBOH1) and hydrogen peroxide production in the apoplast. While apoplastic hydrogen peroxide is essential for the induction of PROTON GRADIENT REGULATIONS (PGR5)-dependent cyclic electron flow, PGR5 participates in the regulation of chilling- and BR-dependent induction of nonphotochemical quenching, accumulation of D1, VDE, and PsbS proteins, transcription of genes involved in redox signaling, hormone signaling, and activity of several antioxidant enzymes. Mutations in BZR1 and PGR5 or suppressed transcription of RBOH1 compromised chilling- and BR-induced photoprotection, resulting in increased sensitivity to photoinhibition. These results demonstrate that BRs act as a positive regulator of photoprotection in a redox-PGR5-dependent manner in response to chilling stress in tomato.