Rapeseed (Brassica napus L.), the second most important oil crop in the world, is extremely vulnerable to drought stress, resulting in severe reductions in yield and quality. Leaf epidermal wax plays an important role in drought stress. However, the genetic basis and regulatory mechanism of wax synthesis in B. napus remain unclear. Here, the integrated analysis of physiology, transcriptome, and metabolome was performed on a glossy mutant under drought stress to reveal the molecular basis of cuticular wax accumulation in rapeseed. Integrated transcriptomic and metabolomic analyses revealed the important roles of unsaturated fatty acids, wax biosynthesis, and plant hormone signal transduction in leaves for enhancing drought tolerance. Several candidate genes were identified to be involved in alkane synthesis and alcohol synthesis of the wax synthesis pathway, including CER1, MYB, FAR3, and MAH1, based on transcriptome and metabolome with weighted gene co-expression network analysis (WGCNA). And RT-qPCR also validated the expression patterns of these candidate genes in the glossy mutant under drought stress. This study provides new insights into the molecular mechanism of leaf epidermis wax synthesis and lays a foundation for breeding drought-resistant varieties and further functional research on the cuticular wax synthesis pathway in rapeseed.

中文翻译：

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干旱胁迫下油菜 （Brassica napus L.） 光泽突变体的生理、转录组和代谢组学综合分析


油菜籽 （Brassica napus L.） 是世界上第二重要的油料作物，极易受到干旱胁迫的影响，导致产量和质量严重下降。叶片表皮蜡在干旱胁迫中起重要作用。然而，甘蓝型油菜蜡合成的遗传基础和调控机制仍不清楚。在这里，对干旱胁迫下的有光泽的突变体进行了生理学、转录组和代谢组的综合分析，以揭示油菜籽表皮蜡质积累的分子基础。综合转录组学和代谢组学分析揭示了叶片中不饱和脂肪酸、蜡质生物合成和植物激素信号转导对增强耐旱性的重要作用。基于加权基因共表达网络分析 （WGCNA） 的转录组和代谢组，确定了几个候选基因参与蜡合成途径的烷烃合成和醇合成，包括 CER1 、 MYB 、 FAR3 和 MAH1。RT-qPCR 还验证了这些候选基因在干旱胁迫下光泽突变体中的表达模式。本研究为叶片表皮蜡合成的分子机制提供了新的见解，为培育抗旱品种和进一步研究油菜籽表皮蜡合成途径的功能研究奠定了基础。