综合生理学和转录组学揭示外源5-氨基乙酰丙酸调节‘德钦'紫花首蓿耐热性的分子机制

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Abstract： In order to reveal the molecular mechanism of exogenous 5-aminolevulinic acid（ALA） regulating Medicago satiua‘Deqin’and provide theoretical basis for heat-resistant breeding，alfalfa leaves with the same growth at for 35 days of seedling age were treated with different concentrations of ALA to screen the optimal concentration of ALA which could aleviate high temperature stress in this study. The leaves separately treated with room temperature without ALA（CK）， high temperature stress without ALA（Heat），sprayed with ALA and cultured at room temperature or under high temperature stress （ALA or HA） were determined physiological indexes and performed transcriptomic sequencing and bioinformatics analysis.The results showed that ALA improved the physiological indexes of alfalfa under high temperature stress at seedling stage，and the relief effect was the best.The differentially expressed genes（DEGs）among the samples were screened，and 27O DEGs were estimated to be potential genes related to the regulation of exogenous ALA in leaf response to high temperature stress.The results of GO and KEGG enrichment and coexpression trends of DEGs indicated that exogenous ALA mainly involved in key genes mediating two pathways，phenylpropanoid biosynthesis and phytohormone signaling，in response to high-temperature stress.This study provided a basis for the mining of heat-resistant genes in alfalfa and laid a theoretical foundation for molecular breeding in the future.

Key words：Medicago satiua； Exogenous ALA；Heat resistance；Phenylpropanoids；Plant hormone

紫花苜蓿（Medicagosatiua）素有“牧草之王"的美誉，因其产量高、营养品质优等特点[1-3]，具有极高的饲喂价值、经济价值和生态价值[4-6]。（剩余19317字）