An Shengmin, Liu Yue, Sang Kangqi, Wang Ting, Yu Jingquan, Zhou Yanhong, Xia Xiaojian
Department of Horticulture, Zhejiang University, Hangzhou, 310058, China.
Hainan Institute, Zhejiang University, Sanya, 572025, China.
J Integr Plant Biol. 2023 Jan;65(1):10-24. doi: 10.1111/jipb.13356. Epub 2023 Jan 4.
Brassinosteroids (BRs) and abscisic acid (ABA) are essential regulators of plant growth and stress tolerance. Although the antagonistic interaction of BRs and ABA is proposed to ensure the balance between growth and defense in model plants, the crosstalk between BRs and ABA in response to chilling in tomato (Solanum lycopersicum), a warm-climate horticultural crop, is unclear. Here, we determined that overexpression of the BR biosynthesis gene DWARF (DWF) or the key BR signaling gene BRASSINAZOLE-RESISTANT1 (BZR1) increases ABA levels in response to chilling stress via positively regulating the expression of the ABA biosynthesis gene 9-CIS-EPOXYCAROTENOID DIOXYGENASE1 (NCED1). BR-induced chilling tolerance was mostly dependent on ABA biosynthesis. Chilling stress or high BR levels decreased the abundance of BRASSINOSTEROID-INSENSITIVE2 (BIN2), a negative regulator of BR signaling. Moreover, we observed that chilling stress increases BR levels and results in the accumulation of BZR1. BIN2 negatively regulated both the accumulation of BZR1 protein and chilling tolerance by suppressing ABA biosynthesis. Our results demonstrate that BR signaling positively regulates chilling tolerance via ABA biosynthesis in tomato. The study has implications in production of warm-climate crops in horticulture.
油菜素甾醇（BRs）和脱落酸（ABA）是植物生长和胁迫耐受性的重要调节因子。尽管有人提出BRs和ABA之间的拮抗相互作用可确保模式植物生长与防御之间的平衡，但在喜温园艺作物番茄（Solanum lycopersicum）中，BRs和ABA在应对低温时的相互作用尚不清楚。在此，我们确定，BR生物合成基因DWARF（DWF）或关键BR信号基因BRASSINAZOLE-RESISTANT1（BZR1）的过表达通过正向调节ABA生物合成基因9-顺式-环氧类胡萝卜素双加氧酶1（NCED1）的表达，提高了番茄对低温胁迫的ABA水平。BR诱导的耐冷性主要依赖于ABA生物合成。低温胁迫或高BR水平降低了BR信号负调节因子BRASSINOSTEROID-INSENSITIVE2（BIN2）的丰度。此外，我们观察到低温胁迫会增加BR水平并导致BZR1的积累。BIN2通过抑制ABA生物合成负调节BZR1蛋白的积累和耐冷性。我们的结果表明，BR信号通过ABA生物合成正向调节番茄的耐冷性。该研究对园艺中喜温作物的生产具有重要意义。
