关键词: 大白菜, 耐盐, 盐敏感, BrSOS基因家族, 盐胁迫, NaCl浓度梯度, 苗期耐盐, 表达分析

Abstract: Double haploid（DH） inbred lines of Chinese cabbage with excellent field comprehensive traits were used as experimental materials. Seed germination tests were conducted using four NaCl concentration gradients（0，170，220，300 mmol/L）via the petri dish germination method，and salt⁃tolerant germplasm at the germination stage was screened by calculating germination potential and germination rate. Furthermore，the salt⁃tolerant and salt⁃sensitive materials obtained from the germination⁃stage screening were further subjected to salt stress treatment at the seedling stage with NaCl concentration gradients of 0，25，50，100，and 150 mmol/L. Growth indicators such as root length and fresh weight were measured to analyze their salt tolerance at the seedling stage. On this basis，using the salt⁃tolerant material HN315 and the salt⁃sensitive material HN44 as core research objects，BrSOS family genes were identified based on the Chinese cabbage whole⁃genome database，and the expression patterns of each gene were analyzed after 36 h of treatment with different NaCl concentrations. The results showed that among 18 Chinese cabbage DH materials，4 salt⁃sensitive materials，4 salt⁃tolerant materials，and 10 intermediate materials were identified. Low⁃concentration NaCl stress could promote the growth of Chinese cabbage to a certain extent，and materials that were salt⁃sensitive at the germination stage still exhibited salt sensitivity at the seedling stage. Gene expression analysis showed that after salt stress treatment，BraA04g013320.3.5C was downregulated in the salt⁃sensitive material HN44，while under high⁃salt conditions，BraA06g032880.3.5C and BraA09g006370.3.5C were significantly upregulated.In the salt⁃tolerant material HN315，BraA04g013320.3.5C and BraA02g044060.3.5C were downregulated，whereas the expression levels of BraA06g032880.3.5C and BraA09g006370.3.5C increased continuously with rising NaCl concentrations.In conclusion，this study completed the evaluation of salt tolerance in Chinese cabbage germplasm through screening at the seed germination and seedling stages，found that BrSOS family genes showed significant expression differences between salt⁃tolerant and salt⁃sensitive Chinese cabbage materials，and clarified that this gene family was a key gene family involved in salt stress response and salt tolerance regulation in Chinese cabbage.

Key words: Chinese cabbage, Salt tolerance, Salt sensitivity, BrSOS gene family, Salt stress, NaCl concentration gradient, Seedling salt tolerance, Expression analysis