Ding Li-Na, Liu Rui, Li Teng, Li Ming, Liu Xiao-Yan, Wang Wei-Jie, Yu Yan-Kun, Cao Jun, Tan Xiao-Li
School of Life Sciences, Jiangsu University, Zhenjiang, China.
Biotechnol Biofuels Bioprod. 2022 May 20;15(1):55. doi: 10.1186/s13068-022-02155-5.
Rapeseed (Brassica napus) is the second largest oil crop worldwide. It is widely used in food, energy production and the chemical industry, as well as being an ornamental. Consequently, it has a large economic value and developmental potential. Waterlogging is an important abiotic stress that restricts plant growth and development. However, little is known about the molecular mechanisms underlying waterlogging tolerance in B. napus.
In the present study, the physiological changes and transcriptomes of germination-stage rapeseed in response to waterlogging stress were investigated in the B. napus cultivar 'Zhongshuang 11' (ZS11) and its anthocyanin-more (am) mutant, which was identified in our previous study. The mutant showed stronger waterlogging tolerance compared with ZS11, and waterlogging stress significantly increased anthocyanin, soluble sugar and malondialdehyde contents and decreased chlorophyll contents in the mutant after 12 days of waterlogging. An RNA-seq analysis identified 1370 and 2336 differently expressed genes (DEGs) responding to waterlogging stress in ZS11 and am, respectively. An enrichment analysis revealed that the DEGs in ZS11 were predominately involved in carbohydrate metabolism, whereas those in the am mutant were particularly enriched in plant hormone signal transduction and response to endogenous stimulation. In total, 299 DEGs were identified as anthocyanin biosynthesis-related structural genes (24) and regulatory genes encoding transcription factors (275), which may explain the increased anthocyanin content in the am mutant. A total of 110 genes clustered in the plant hormone signal transduction pathway were also identified as DEGs, including 70 involved in auxin and ethylene signal transduction that were significantly changed in the mutant. Furthermore, the expression levels of 16 DEGs with putative roles in anthocyanin accumulation and biotic/abiotic stress responses were validated by quantitative real-time PCR as being consistent with the transcriptome profiles.
This study provides new insights into the molecular mechanisms of increased anthocyanin contents in rapeseed in response to waterlogging stress, which should be useful for reducing the damage caused by waterlogging stress and for further breeding new rapeseed varieties with high waterlogging tolerance.
油菜（甘蓝型油菜）是全球第二大油料作物。它广泛应用于食品、能源生产和化学工业，同时还具有观赏价值。因此，它具有巨大的经济价值和发展潜力。涝害是限制植物生长发育的一种重要非生物胁迫。然而，关于甘蓝型油菜耐涝性的分子机制知之甚少。
在本研究中，对甘蓝型油菜品种‘中双11’（ZS11）及其花青素含量更高（am）的突变体（该突变体是在我们之前的研究中鉴定出来的）在萌发期响应涝害胁迫的生理变化和转录组进行了研究。与ZS11相比，该突变体表现出更强的耐涝性，涝害胁迫12天后，突变体中的花青素、可溶性糖和丙二醛含量显著增加，叶绿素含量降低。RNA测序分析分别在ZS11和am中鉴定出1370个和2336个响应涝害胁迫的差异表达基因（DEG）。富集分析表明，ZS11中的DEG主要参与碳水化合物代谢，而am突变体中的DEG特别富集于植物激素信号转导和对内源刺激的响应。总共鉴定出299个DEG为花青素生物合成相关的结构基因（24个）和编码转录因子的调控基因（275个），这可能解释了am突变体中花青素含量的增加。在植物激素信号转导途径中聚类的总共110个基因也被鉴定为DEG，其中包括70个参与生长素和乙烯信号转导的基因，这些基因在突变体中发生了显著变化。此外，通过定量实时PCR验证了16个在花青素积累和生物/非生物胁迫响应中具有假定作用的DEG的表达水平与转录组图谱一致。
本研究为油菜响应涝害胁迫时花青素含量增加的分子机制提供了新的见解，这对于减少涝害胁迫造成的损害以及进一步培育耐涝性高的油菜新品种应该是有用的。
