State Key Laboratory of Crop Genetics & Germplasm Enhancement, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (East China), Ministry of Agriculture and Rural Affairs, PR China; Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education, PR China; Nanjing Suman Plasma Engineering Research Institute, Nanjing Agricultural University, Nanjing 210095, China.
State Key Laboratory of Crop Genetics & Germplasm Enhancement, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (East China), Ministry of Agriculture and Rural Affairs, PR China; Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education, PR China.
Plant Sci. 2022 Aug;321:111291. doi: 10.1016/j.plantsci.2022.111291. Epub 2022 Apr 30.
Cold stress is a key factor limiting the yield and quality of non-heading Chinese cabbage. The hydrophilic protective protein LEA plays an important role in plant abiotic stress. In this study, 72 BcLEAs were identified from non-heading Chinese cabbage and divided into 9 subfamilies by phylogenetic analysis. Gene structure analysis showed that BcLEAs were unevenly distributed on 10 chromosomes, with few introns. Through analyzing the expression of these genes under cold stress by RNA-seq and qRT-PCR, two genes (BcLEA4-7 and BcLEA4-18) highly sensitive to cold stress were identified, whose roles in cold tolerance of non-heading Chinese cabbage were demonstrated by virus-induced gene silencing. The BcLEA promoters were analyzed to study the cold response mechanism of BcLEA4-7 and BcLEA4-18, revealing that both BcLEA4-7 and BcLEA4-18 promoters contained two CRT/DRE elements. Subsequently, it was found that the promoters isolated from non-heading Chinese cabbage could be activated at low temperatures. Further analysis showed BcCBF2 in non-heading Chinese cabbage interacted with two CRT/DRE elements in BcLEA4-7 and BcLEA4-18 promoters to stimulate their activity, indicating that BcCBF2 is an upstream regulator. Meanwhile, the CRT/DRE element located in BcLEA4-7 promoter (-219 bp to -171 bp) and BcLEA4-18 promoter (-234 bp to -186 bp) was more likely to be activated by BcCBF2, which may be attributed to its flanking sequence. These data laid a foundation for further understanding the functional role and regulatory mechanism of BcLEAs in cold stress tolerance.
冷胁迫是限制不结球白菜产量和品质的关键因素。亲水性保护蛋白 LEA 在植物非生物胁迫中发挥重要作用。本研究从不结球白菜中鉴定出 72 个 BcLEAs，并通过系统进化分析将其分为 9 个亚家族。基因结构分析表明，BcLEAs 不均匀分布在 10 条染色体上，内含子较少。通过 RNA-seq 和 qRT-PCR 分析这些基因在冷胁迫下的表达，鉴定出两个对冷胁迫高度敏感的基因（BcLEA4-7 和 BcLEA4-18），并通过病毒诱导的基因沉默证明了它们在不结球白菜耐冷性中的作用。对 BcLEA 启动子进行分析，研究 BcLEA4-7 和 BcLEA4-18 的冷响应机制，发现 BcLEA4-7 和 BcLEA4-18 启动子均含有两个 CRT/DRE 元件。随后发现，从不结球白菜中分离的启动子可以在低温下被激活。进一步分析表明，不结球白菜中的 BcCBF2 与 BcLEA4-7 和 BcLEA4-18 启动子中的两个 CRT/DRE 元件相互作用，刺激其活性，表明 BcCBF2 是一个上游调节因子。同时，位于 BcLEA4-7 启动子（-219 bp 至-171 bp）和 BcLEA4-18 启动子（-234 bp 至-186 bp）中的 CRT/DRE 元件更有可能被 BcCBF2 激活，这可能归因于其侧翼序列。这些数据为进一步了解 BcLEAs 在冷胁迫耐受中的功能作用和调控机制奠定了基础。
