褪黑素对盐胁迫下普通菜豆芽期核酸修复的调控机制

The Regulatory Mechanism of Melatonin on Nucleic Acid Repairing of Common Bean (Phaseolus vulgaris) at the Sprout Stage Under Salt Stress

普通菜豆(Phaseolus vulgaris)是重要的食用豆作物,然而其极易受盐胁迫危害,导致产量下降。褪黑素能提高植物耐盐能力。为探明外源褪黑素调控普通菜豆耐盐能力的机制,以普通菜豆品种奶花芸豆(GZ-YD014)为实验材料,设置水(W,对照)、盐胁迫(S)和盐胁迫+100μmol·L^(–1)褪黑素(M+S)3个处理。结果发现,盐胁迫抑制了普通菜豆胚根的生长,使其长度、表面积、体积以及直径显著降低,外源褪黑素可缓解盐胁迫对普通菜豆胚根生长的抑制。外施褪黑素显著降低盐胁迫下活性氧积累和丙二醛(MDA)含量,提高保护酶(过氧化物酶、超氧化物歧化酶、过氧化氢酶以及抗坏血酸过氧化物酶)活性,增加渗透调节物质(可溶性糖和可溶性蛋白)以及生长素(IAA)、赤霉素(GA)和玉米素(ZT)的含量,降低脱落酸(ABA)含量。通过转录组分析挖掘出217个差异表达基因(DEGs),DEGs在GO富集中显著(P-value<0.05)富集到核酸相关条目上,在KEGG富集中显著(P-value<0.05)富集到核酸损伤修复(包括碱基切除修复、错配修复以及核苷酸切除修复)通路。qRT-PCR以及RAPD分析结果表明,核酸损伤修复通路为外源褪黑素调控普通菜豆耐盐能力的一种机制。该研究揭示了外源褪黑素对普通菜豆芽期耐盐能力的调控机制,可为褪黑素应用于盐胁迫下普通菜豆增产提供理论依据。

Common bean(Phaseolus vulgaris)is an important bean crop but it is highly susceptible to salt stress which causes yield decrease.Melatonin can improve the salt tolerance of plants.However,the mechanism of exogenous melatonin in regulating the salt tolerance of common bean has not been explored.In this study,the common bean variety Naihua common bean(GZ-YD014)was used as materials,and three treatments were set for comparisons,including water(W,control),salt stress(S),and salt stress+100μmol·L^(–1)melatonin(M+S).The results showed that salt stress inhibited the growth of sprouts,whose length,surface area,volume and diameter decreased significantly under salt stress conditions.Exogenous melatonin alleviated the inhibition of salt stress on the growth of common bean sprouts by significantly reducing the accumulation of reactive oxygen species(ROS)and malondialdehyde(MDA)content,increasing protective enzymes such as peroxidase,superoxide dismutase,catalase and ascorbate peroxidase,osmotic regulators including soluble sugar and soluble protein content,auxin(IAA),gibberellin(GA),zeatin(ZT)content,and decreasing abscisic acid(ABA)content.Transcriptome analysis discovered 217 differentially expressed genes(DEGs),which were significantly enriched(P-value<0.05)in the nucleic acid-related entries by GO enrichment analysis and also in the nucleic acid damage repair(including base excision repair,mismatch repair and nucleotide excision repair)pathways by KEGG enrichment analysis(P-value<0.05).Real-time quantitative PCR and random amplified polymorphism analysis proved that the nucleic acid damage repair was a mechanism of exogenous melatonin regulating the salt tolerance of common bean.The study revealed the mechanism of exogenous melatonin regulating the salt tolerance of common bean sprouts,and provided a theoretical basis for the application of melatonin in common bean to increase yield under salt stress.