褪黑素对干旱胁迫下花椒影响的生理和转录组分析

Physiological and Transcriptomic Analyses of the Effects of Melatonin on Zanthoxylum bungeanum Under Drought Stress

为了探究褪黑素(MT)对干旱胁迫下花椒的影响和调控机制,以花椒幼苗为试验材料,叶面喷施200μmol·L^(-1)的褪黑素后进行干旱处理,在胁迫第1天和第7天测定光系统Ⅱ最大光化学效率(Fv/Fm)、光合电子传递速率(ETR)、活性氧(ROS)含量、丙二醛(MDA)含量、抗氧化酶活性和可溶性糖(SS)含量,并进行转录组分析。结果表明,MT处理的叶片表现出比未处理叶片更高的Fv/Fm、ETR、抗氧化酶活性、SS以及更低的ROS和MDA含量。京都基因与基因组百科全书(KEGG)富集的重要通路是淀粉与蔗糖代谢和植物激素信号转导。MT上调了淀粉与蔗糖代谢途径中与蔗糖磷酸合酶相关基因的表达,催化蔗糖合成,从而使可溶性糖含量增加,这与生理水平上可溶性糖含量升高趋势一致。MT也促进了植物激素信号转导途径中生长素亚途径与AUX1、AUX/IAA、ARF及GH3相关的基因表达上调。综上所述,干旱胁迫抑制花椒幼苗的生长,而施用MT可以缓解干旱胁迫对花椒的伤害,提高其抗旱能力。

In order to explore the effects and regulation mechanisms of melatonin(MT)on Zanthoxylum bungeanum under drought stress,the PSII maximum photochemical efficiency(Fv/Fm),electron transfer rate(ETR),reactive oxygen species(ROS)content,malondialdehyde(MDA)content,antioxidant enzyme activity and soluble sugar(SS)content in the seedlings of Z.bungeanum with 200μmol·L^(-1) melatonin application were analyzed after drought stress,and transcriptome analysis was carried out.The results indicated that MT-treated plants showed higher Fv/Fm,ETR,antioxidant enzyme activity and SS content,as well as lower ROS and MDA contents than those untreated plants.The important pathway of Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment were starch and sucrose metabolism and plant hormone signal transduction.MT up-regulated the expression of genes related to sucrose phosphate synthase in the starch and sucrose metabolic pathway of Z.bungeanum under drought stress,induced the sucrose synthesis and increased soluble sugar content,which was consistent with the increasing trend of soluble sugar content at the physiological level.Meanwhile,MT also promoted the up-regulation of AUX1,AUX/IAA,ARF and GH3 related genes in plant hormone signal transduction pathway.In conclusion,drought stress inhibits the growth of Z.bungeanum seedlings.The application of MT cand ameliorate drought-induced damages and improve the drought resistance of Z.bungeanum.