Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong 637009, China.
Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong 637009, China.
Plant Sci. 2022 Jul;320:111281. doi: 10.1016/j.plantsci.2022.111281. Epub 2022 Apr 4.
Brassinosteroids (BRs) regulate plant development and response to stress. BRASSINOSTEROID INSENSITIVE 1 (BRI1) is a BR receptor that activates BR signaling. Although the function of the tomato BR receptor SlBRI1 in regulating growth and drought resistance has been examined, that of SlBRI1 in cold tolerance is unclear. This study indicated that the expression of SlBRI1 in tomato was rapidly induced and reached its highest level at 3 h under chilling treatment and then decreased. The overexpression of SlBRI1 displayed low relative electrolyte leakage, malondialdehyde content, and reactive oxygen species (ROS) accumulation under chilling stress. The proline content and activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in SlBRI1OE plants were higher than those in the wild-type (WT) plants after chilling stress. The transcript abundances of five cold-responsive genes were higher in SlBRI1OE plants than in WT plants during chilling stress. RNA sequence analysis showed that the expression of the majority of genes encoding photosystem I and II were downregulated. The degree of suppression in SlBRI1OE plants was weaker than that in WT plants. Additionally, the Pn and Fv/Fm of SlBRI1OE plants were significantly higher than those of WT plants under chilling stress. We identified several genes encoding key enzymes in BRs; indole acetic acid (IAA), gibberellin (GA), and abscisic acid (ABA) biosynthesis or signaling were upregulated or downregulated during chilling stress. Chilling stress decreased the BRs and GA3 content, and increased IAA and ABA content. The contents were lower or higher in SlBRI1OE than in WT plants. Furthermore, chilling stress regulated the expression levels of 43 transcription factors. The expression of seven cold-regulated protein genes was higher or lower in SlBRI1OE plants than in WT plants under chilling stress. These results suggest that SlBRI1 positively regulates chilling tolerance mainly through ICE1-CBF-COR pathway in tomato.
油菜素甾醇（BRs）调节植物的发育和对胁迫的响应。BRASSINOSTEROID INSENSITIVE 1（BRI1）是一种 BR 受体，能激活 BR 信号。尽管番茄 BR 受体 SlBRI1 调节生长和抗旱性的功能已被研究，但它在耐寒性方面的功能尚不清楚。本研究表明，在番茄中 SlBRI1 的表达在冷胁迫下迅速诱导，在 3 h 时达到最高水平，然后下降。过表达 SlBRI1 可在冷胁迫下显示较低的相对电解质渗出率、丙二醛含量和活性氧（ROS）积累。冷胁迫后，SlBRI1OE 植株脯氨酸含量和超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性均高于野生型（WT）植株。在冷胁迫下，SlBRI1OE 植物中五个冷响应基因的转录丰度均高于 WT 植物。RNA 序列分析表明，大多数编码光系统 I 和 II 的基因的表达下调。SlBRI1OE 植物的抑制程度弱于 WT 植物。此外，冷胁迫下 SlBRI1OE 植物的 Pn 和 Fv/Fm 明显高于 WT 植物。我们鉴定了几个编码 BRs 中关键酶的基因；吲哚乙酸（IAA）、赤霉素（GA）和脱落酸（ABA）的生物合成或信号在冷胁迫下被上调或下调。冷胁迫降低了 BRs 和 GA3 的含量，增加了 IAA 和 ABA 的含量。SlBRI1OE 中的含量低于或高于 WT 植物。此外，冷胁迫调节了 43 个转录因子的表达水平。冷胁迫下 SlBRI1OE 植物中七个冷调节蛋白基因的表达高于或低于 WT 植物。这些结果表明，SlBRI1 通过番茄中的 ICE1-CBF-COR 途径正向调控耐冷性。
