Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.
Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.
Plant Physiol Biochem. 2024 Sep;214:108926. doi: 10.1016/j.plaphy.2024.108926. Epub 2024 Jul 9.
Leucaena leucocephala (Leucaena) is a leguminous tree widely cultivated in tropical and subtropical regions due to its strong environmental suitability for abiotic stresses, especially drought. However, the molecular mechanisms and key pathways involved in Leucaena's drought response require further elucidation. Here, we comparatively analyzed the physiological and early transcriptional responses of Leucaena leaves and roots under drought stress simulated by polyethylene glycol (PEG) treatments. Drought stress induced physiological changes in Leucaena seedlings, including decreases in relative water content (RWC) and increases in relative electrolyte leakage (REL), malondialdehyde (MDA), proline contents as well as antioxidant enzyme activities. In response to drought stress, 6461 and 8295 differentially expressed genes (DEGs) were identified in the leaves and roots, respectively. In both tissues, the signaling transduction pathway of plant hormones was notably the most enriched. Specifically, abscisic acid (ABA) biosynthesis and signaling related genes (NCED, PP2C, SnRK2 and ABF) were strongly upregulated particularly in leaves. The circadian rhythm, DNA replication, alpha-linolenic acid metabolism, and secondary metabolites biosynthesis related pathways were repressed in leaves, while the glycolysis/gluconeogenesis and alpha-linolenic acid metabolism and amino acid biosynthesis processes were promoted in roots. Furthermore, heterologous overexpression of Leucaena drought-inducible genes (PYL5, PP2CA, bHLH130, HSP70 and AUX22D) individually in yeast increased the tolerance to drought and heat stresses. Overall, these results deepen our understanding of the tissue-specific mechanisms of Leucaena in response to drought and provide target genes for future drought-tolerance breeding engineering in crops.
银合欢（Leucaena）是一种豆科树木，由于其对非生物胁迫（尤其是干旱）具有很强的环境适应性，因此在热带和亚热带地区广泛种植。然而，银合欢对干旱的响应的分子机制和关键途径尚需进一步阐明。在这里，我们比较分析了聚乙二醇（PEG）处理模拟干旱胁迫下银合欢叶片和根系的生理和早期转录响应。干旱胁迫导致银合欢幼苗发生生理变化，包括相对水含量（RWC）降低和相对电解质泄漏（REL）、丙二醛（MDA）、脯氨酸含量以及抗氧化酶活性增加。在受到干旱胁迫时，叶片和根系中分别鉴定出 6461 个和 8295 个差异表达基因（DEGs）。在这两种组织中，植物激素信号转导途径是最显著的富集途径。具体来说，ABA 生物合成和信号相关基因（NCED、PP2C、SnRK2 和 ABF）在叶片中强烈上调。叶片中昼夜节律、DNA 复制、α-亚麻酸代谢和次生代谢物生物合成相关途径被抑制，而根系中糖酵解/糖异生和α-亚麻酸代谢和氨基酸生物合成过程被促进。此外，在酵母中异源过表达银合欢干旱诱导基因（PYL5、PP2CA、bHLH130、HSP70 和 AUX22D）可单独提高对干旱和热胁迫的耐受性。总体而言，这些结果加深了我们对银合欢响应干旱的组织特异性机制的理解，并为未来作物的耐旱性育种工程提供了目标基因。
