Shi Yaqiong, Jin Zihao, Wang Jingyi, Zhou Guangkuo, Wang Fang, Peng Yunling
College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China.
State Key Laboratory of Aridland Crop Science, Lanzhou 730070, China.
Int J Mol Sci. 2024 Dec 2;25(23):12963. doi: 10.3390/ijms252312963.
Drought stress seriously affects the growth, development, yield, and quality of maize. This study aimed to investigate the effects of exogenous 5-ALA on root morphology and physiological changes in maize seedlings and to detect its regulatory network. The results showed that adding 25 mg/L 5-ALA accelerated root morphogenesis (root average diameter, main root length, total root length, and root surface area) and promoted dry matter accumulation and free radical removal. Transcriptome analysis showed that after applying exogenous 5-ALA, differently expressed genes (DEGs) were mainly involved in histidine metabolism, amino acid biosynthesis, plasma membrane components, secondary active sulfate transmembrane transporter activity, and anion reverse transporter activity. Two inbred lines specifically responded to organelle and structural molecular activity, and 5-ALA may regulate maize roots to achieve drought tolerance through these two pathways. In addition, candidate genes that may regulate maize root growth were screened by weighted gene co-expression network analysis (WGCNA). These genes may play important roles in alleviating drought stress through lignin synthesis, heat shock proteins, iron storage and transport, calcium binding proteins, and plasma membrane regulation of exogenous regulator 5-ALA. Our results may provide a theoretical basis for clarifying the response of maize seedling roots to drought and the mechanism of exogenous hormones in alleviating drought.
干旱胁迫严重影响玉米的生长、发育、产量和品质。本研究旨在探讨外源5-氨基乙酰丙酸（5-ALA）对玉米幼苗根系形态和生理变化的影响，并检测其调控网络。结果表明，添加25 mg/L的5-ALA可加速根系形态建成（根平均直径、主根长度、总根长度和根表面积），促进干物质积累和自由基清除。转录组分析表明，施加外源5-ALA后，差异表达基因（DEGs）主要参与组氨酸代谢、氨基酸生物合成、质膜成分、次级活性硫酸盐跨膜转运蛋白活性和阴离子反向转运蛋白活性。两个自交系对细胞器和结构分子活性有特异性响应，5-ALA可能通过这两条途径调节玉米根系以实现耐旱性。此外，通过加权基因共表达网络分析（WGCNA）筛选出可能调控玉米根系生长的候选基因。这些基因可能通过木质素合成、热休克蛋白、铁储存和运输、钙结合蛋白以及外源调节剂5-ALA的质膜调节在缓解干旱胁迫中发挥重要作用。我们的研究结果可能为阐明玉米幼苗根系对干旱的响应以及外源激素缓解干旱的机制提供理论依据。
