Key Laboratory of Mass Spectrometry Imaging and Metabolomics, Minzu University of China, National Ethnic Affairs Commission, Beijing 100081, China.
Key Laboratory of Ecology and Environment in Minority Areas, Minzu University of China, National Ethnic Affairs Commission, Beijing 100081, China.
Biomolecules. 2024 Feb 16;14(2):227. doi: 10.3390/biom14020227.
Plant cuticular wax forms a hydrophobic structure in the cuticle layer covering epidermis as the first barrier between plants and environments. , a leguminous desert shrub, exhibits high tolerances to multiple abiotic stress. The physiological, chemical, and transcriptomic analyses of epidermal permeability, cuticular wax metabolism and related gene expression profiles under osmotic stress in leaves were performed. Physiological analyses revealed decreased leaf epidermal permeability under osmotic stress. Chemical analyses revealed saturated straight-chain alkanes as major components of leaf cuticular wax, and under osmotic stress, the contents of total wax and multiple alkane components significantly increased. Transcriptome analyses revealed the up-regulation of genes involved in biosynthesis of very-long-chain fatty acids and alkanes and wax transportation under osmotic stress. Weighted gene co-expression network analysis identified 17 modules and 6 hub genes related to wax accumulation, including 5 enzyme genes coding KCS, KCR, WAX2, FAR, and LACS, and an ABCG transporter gene. Our findings indicated that the leaf epidermal permeability of decreased under osmotic stress to inhibit water loss via regulating the expression of wax-related enzyme and transporter genes, further promoting cuticular wax accumulation. This study provided new evidence for understanding the roles of cuticle lipids in abiotic stress tolerance of desert plants.
植物角质层蜡质在表皮层形成疏水性结构，作为植物与环境之间的第一道屏障。作为一种豆科沙漠灌木，具有较高的耐多种非生物胁迫能力。对渗透胁迫下 叶片的表皮通透性、角质层蜡质代谢及相关基因表达谱进行了生理、化学和转录组分析。生理分析表明，渗透胁迫下叶片表皮通透性降低。化学分析表明，饱和直链烷烃是叶片角质层蜡质的主要成分，渗透胁迫下，总蜡质和多种烷烃成分的含量显著增加。转录组分析表明，参与合成超长链脂肪酸和烷烃以及蜡质转运的基因在渗透胁迫下上调。加权基因共表达网络分析鉴定出 17 个与蜡质积累相关的模块和 6 个枢纽基因，包括 5 个编码 KCS、KCR、WAX2、FAR 和 LACS 的酶基因，以及一个 ABCG 转运体基因。我们的研究结果表明，渗透胁迫下 叶片表皮通透性降低，通过调节蜡相关酶和转运体基因的表达来抑制水分流失，进一步促进角质层蜡质的积累。本研究为理解角质层脂质在沙漠植物非生物胁迫耐受中的作用提供了新的证据。
