Kuang Qian, Ding Rui, Huang Die, He Chenggang, Jiang Hua
Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming, 650201, China.
BMC Genomics. 2025 Jul 9;26(1):649. doi: 10.1186/s12864-025-11845-x.
As a tetraploid plant, alfalfa ( L.) exhibits complex genetic mechanisms that pose significant challenges for the integration and stabilization of superior traits. In this study, space mutagenesis–a highly efficient and stochastic gene mutation induction technique–was employed to treat ‘Deqin’ alfalfa seeds. Through ground-based selection, a mutant line with enlarged leaves was identified. However, the molecular mechanisms underlying leaf enlargement remain unexplored.
Integrated transcriptomic, targeted phytohormone metabolomic, and microstructural analyses were used to reveal the mechanistic basis of leaf enlargement in the mutant. The results showed that cell size increased significantly, the palisade and spongy mesophyll tissues thickened notably, and photosynthesis was markedly enhanced. Transcriptome analysis identified a total of 28,060 expressed genes in the leaves, among which 2,009 differentially expressed genes were upregulated and 2,082 were downregulated. Enrichment analysis revealed that pathways such as ribosome, biosynthesis of amino acids, photosynthesis, plant-pathogen interaction, starch and sucrose metabolism, and phenylpropanoid biosynthesis were significantly involved in the leaf enlargement process. Targeted plant hormone metabolomics analysis showed that the levels of abscisic acid, jasmonic acid (JA), 3-indolebutyric acid, 3-indolepropionic acid, and 1-aminocyclopropane-1-carboxylic acid increased by 200.76%, 98.35%, 97.70%, 69.72%, and 27.89%, respectively, compared with those in the control. In contrast, salicylic acid and JA-isoleucine levels decreased by 62.21% and 14.01%, respectively. Combined transcriptomic and metabolomic analysis indicated that metabolic pathways, biosynthesis of secondary metabolites, and hormone signal transduction were the most significantly enriched pathways. Furthermore, a protein-protein interaction network analysis identified , , and as key genes involved in these pathways.
This study revealed the core regulatory roles of energy metabolism, secondary metabolite biosynthesis, and plant hormone signaling networks in the process of leaf enlargement in the mutant, and identified target genes. These findings lay a solid theoretical foundation for the breeding of high-yield, high-quality alfalfa varieties and provide valuable material resources.
The online version contains supplementary material available at 10.1186/s12864-025-11845-x.
作为一种四倍体植物，苜蓿（Medicago sativa L.）表现出复杂的遗传机制，这给优良性状的整合和稳定带来了重大挑战。在本研究中，利用空间诱变——一种高效且随机的基因突变诱导技术——处理‘德钦’苜蓿种子。通过地面筛选，鉴定出一个叶片增大的突变系。然而，叶片增大背后的分子机制仍未被探索。
采用综合转录组学、靶向植物激素代谢组学和微观结构分析来揭示突变体叶片增大的机制基础。结果表明，细胞大小显著增加，栅栏组织和海绵组织明显增厚，光合作用显著增强。转录组分析在叶片中总共鉴定出28,060个表达基因，其中2,009个差异表达基因上调，2,082个下调。富集分析表明，核糖体、氨基酸生物合成、光合作用、植物 - 病原体相互作用、淀粉和蔗糖代谢以及苯丙烷生物合成等途径显著参与叶片增大过程。靶向植物激素代谢组学分析表明，与对照相比，脱落酸、茉莉酸（JA）、3 - 吲哚丁酸、3 - 吲哚丙酸和1 - 氨基环丙烷 - 1 - 羧酸的水平分别增加了200.76%、98.35%、97.70%、69.72%和27.89%。相比之下，水杨酸和茉莉酸异亮氨酸水平分别下降了62.21%和14.01%。转录组和代谢组联合分析表明，代谢途径、次生代谢物生物合成和激素信号转导是最显著富集的途径。此外，蛋白质 - 蛋白质相互作用网络分析确定了[具体基因名称未给出]、[具体基因名称未给出]和[具体基因名称未给出]为参与这些途径的关键基因。
本研究揭示了能量代谢、次生代谢物生物合成和植物激素信号网络在突变体叶片增大过程中的核心调控作用，并鉴定了靶基因。这些发现为高产、优质苜蓿品种的培育奠定了坚实的理论基础，并提供了宝贵的材料资源。
在线版本包含可在10.1186/s12864 - 025 - 11845 - x获取的补充材料。
