State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China.
Heilongjiang Academy of Forestry, 143 Haping Road, Harbin, 150081, China.
BMC Plant Biol. 2024 Nov 28;24(1):1136. doi: 10.1186/s12870-024-05738-6.
Salt stress is one of the major environmental factors affecting plant growth and productivity. BRI1-EMS suppressor 1/brassinazole-resistant 1 ((BES1/BZR1) plays an important role in responding to abiotic stress in plants. Although the impacts of BES1/BZR1 on plant growth and resistance have been documented, the potential mechanisms are not fully elucidated in Betula platyphylla. This work contributes to the understanding of how BES1/BZR1 promotes stress tolerance in woody plants.
Six BES1/BZR1 family members were identified from Betula platyphylla. Cis-element analysis showed that the promoters of six genes were rich in ABA-responsive element (ABRE), MYB and MBS cis-acting elements, which are reported to be involved in abiotic stress responses. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that BpBZR1-6 (BPChr10G06000) could be induced by salt stress, ABA and BRs. BpBZR1-6 was localized in the nucleus and had transactivation activity. Ectopic expression of BpBZR1-6 enhanced Arabidopsis tolerance and decreased abscisic acid (ABA) sensitivity under salt treatment. Specifically, the seed germination rate, root length, fresh weight and chlorophyll content were significantly higher in BpBZR1-6-overexpressing (OE) transgenic plants than in wild-type (WT) plants after salt stress (P < 0.05). Additionally, BpBZR1-6 overexpression showed enhanced the reactive oxygen species (ROS) scavenging capability under salt stress, including increasing the activities of antioxidant enzyme, resulting in a decrease in O and HO accumulation, and reducing malondialdehyde (MDA) content. Meanwhile, the expression levels of six antioxidant enzyme genes were higher in OE plants than in WT plants after stress.
BpBZR1-6 overexpression enhanced the salt tolerance of transgenic plants by modulating antioxidant enzyme gene expression and ROS scavenging, which may provide underlying strategy for breeding of salt-tolerant plants.
盐胁迫是影响植物生长和生产力的主要环境因素之一。BRI1-EMS 抑制剂 1/油菜素内酯抗性 1（BES1/BZR1）在植物应对非生物胁迫中发挥重要作用。尽管已经记录了 BES1/BZR1 对植物生长和抗性的影响，但在白桦中其潜在机制尚未完全阐明。这项工作有助于理解 BES1/BZR1 如何促进木本植物的胁迫耐受性。
从白桦中鉴定出 6 个 BES1/BZR1 家族成员。顺式作用元件分析表明，6 个基因的启动子富含 ABA 响应元件（ABRE）、MYB 和 MBS 顺式作用元件，这些元件被报道参与非生物胁迫反应。定量实时聚合酶链反应（qRT-PCR）分析表明，BpBZR1-6（BPChr10G06000）可以被盐胁迫、ABA 和 BRs 诱导。BpBZR1-6 定位于细胞核内，具有转录激活活性。BpBZR1-6 的异位表达增强了拟南芥的耐盐性，并降低了盐处理下的 ABA 敏感性。具体来说，在盐胁迫后，BpBZR1-6 过表达（OE）转基因植物的种子发芽率、根长、鲜重和叶绿素含量均显著高于野生型（WT）植物（P<0.05）。此外，BpBZR1-6 过表达增强了盐胁迫下的活性氧（ROS）清除能力，包括提高抗氧化酶的活性，导致 O 和 HO 积累减少，丙二醛（MDA）含量降低。同时，胁迫后 OE 植物中六种抗氧化酶基因的表达水平高于 WT 植物。
BpBZR1-6 的过表达通过调节抗氧化酶基因表达和 ROS 清除来增强转基因植物的耐盐性，这可能为培育耐盐植物提供了潜在策略。
