Liu Zhujun, Shi Xinxin, Wang Zhibo, Qu Ming, Gao Caiqiu, Wang Chao, Wang Yucheng
State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
Plant Physiol. 2024 Jun 28;195(3):2354-2371. doi: 10.1093/plphys/kiae168.
Teosinte branched 1/Cycloidea/Proliferating cell factor (TCP) transcription factors function in abiotic stress responses. However, how TCPs confer salt tolerance is unclear. Here, we characterized a TCP transcription factor, BpTCP20, that responds to salt stress in birch (Betula platyphylla Suk). Plants overexpressing BpTCP20 displayed increased salt tolerance, and Bptcp20 knockout mutants displayed reduced salt tolerance relative to the wild-type (WT) birch. BpTCP20 conferred salt tolerance by mediating stomatal closure and reducing reactive oxygen species (ROS) accumulation. Chromatin immunoprecipitation sequencing showed that BpTCP20 binds to NeuroD1, T-box, and two unknown elements (termed TBS1 and TBS2) to regulate target genes. In birch, salt stress led to acetylation of BpTCP20 acetylation at lysine 259. A mutated BpTCP20 variant (abolished for acetylation, termed BpTCP20259) was overexpressed in birch, which led to decreased salt tolerance compared with plants overexpressing BpTCP20. However, BpTCP20259-overexpressing plants still displayed increased salt tolerance relative to untransformed WT plants. BpTCP20259 showed reduced binding to the promoters of target genes and decreased target gene activation, leading to decreased salt tolerance. In addition, we identified dihydrolipoyllysine-residue acetyltransferase component of pyruvate dehydrogenase complex (BpPDCE23), an acetyltransferase that interacts with and acetylates BpTCP20 to enhance its binding to DNA motifs. Together, these results suggest that BpTCP20 is a transcriptional regulator of salt tolerance, whose activity is modulated by BpPDCE23-mediated acetylation.
玉米分枝1/环化蛋白/增殖细胞因子（TCP）转录因子在非生物胁迫响应中发挥作用。然而，TCP如何赋予植物耐盐性尚不清楚。在此，我们鉴定了一种TCP转录因子BpTCP20，它在白桦（Betula platyphylla Suk）中对盐胁迫作出响应。过表达BpTCP20的植物表现出耐盐性增强，而Bptcp20敲除突变体相对于野生型（WT）白桦表现出耐盐性降低。BpTCP20通过介导气孔关闭和减少活性氧（ROS）积累来赋予耐盐性。染色质免疫沉淀测序表明，BpTCP20与NeuroD1、T-box以及两个未知元件（称为TBS1和TBS2）结合以调控靶基因。在白桦中，盐胁迫导致BpTCP20在赖氨酸259处发生乙酰化。一种突变的BpTCP20变体（乙酰化被消除，称为BpTCP20259）在白桦中过表达，与过表达BpTCP20的植物相比，其耐盐性降低。然而，过表达BpTCP20259的植物相对于未转化的WT植物仍表现出耐盐性增强。BpTCP20259与靶基因启动子的结合减少，靶基因激活降低，导致耐盐性降低。此外，我们鉴定了丙酮酸脱氢酶复合物的二氢硫辛酰赖氨酸残基乙酰转移酶组分（BpPDCE23），一种与BpTCP20相互作用并使其乙酰化以增强其与DNA基序结合的乙酰转移酶。总之，这些结果表明BpTCP20是耐盐性的转录调节因子，其活性受BpPDCE23介导的乙酰化调节。
