干旱胁迫下热带和温带玉米种质的生理及转录组分析

Physiological and Transcriptomic Analyses of Tropical and Temperate Maize Germplasms

通过分析热带和温带玉米自交系干旱胁迫下的苗期生理和转录组数据,阐明不同玉米种质对干旱胁迫的生理和分子响应机制。结果表明,干旱胁迫下4个自交系的过氧化物酶(POD)、超氧化物歧化酶(SOD)活性以及丙二醛(MDA)、可溶性糖和可溶性蛋白质含量上升,叶绿素含量和4个叶绿素荧光参数值(F_(v)/F_(o)、F_(v)/F_(m)、Φ_(PSII)和Q_(P))下降,温带玉米自交系较热带自交系的变化幅度更大。4个自交系在对照(CK)和干旱处理条件下的过滤后序列数(Clean reads)变幅为44560000~52580000条,4个自交系干旱胁迫下共有20126个差异表达基因(DEGs),21个基因本体项(GO terms)的相关基因高度富集。此外,热带和温带玉米自交系对干旱存在生理和分子响应差异,热带玉米种质的耐旱性高于温带玉米种质,可在热带种质中筛选耐旱玉米种质。

Comparative physiological and transcriptomic analyses of tropical and temperate maize lines were performed to understand physiological and molecular responses of different maize germplasms subjected to water deficits at the stage of seedling.The results indicated that there were considerable increases in POD and SOD activities,and MDA,soluble carbohydrate,and soluble protein contents under drought stress.In contrast,the chlorophyll content and four chlorophyll fluorescence parameters(F_(v)/F_(o)、F_(v)/F_(m)、Φ_(PSII)andQ_(P))decreased in all four lines in responses to drought stress.Additionally,tropical maize lines maintain relatively higher values for the chlorophyll content and four chlorophyll fluorescence parameters than those of the temperate lines.On average,after the raw data had been filtered,RNA-Seq experiments yielded between 44.56 and 52.58 million paired-end reads per sample.For the four different maize lines under drought stress,20126 differentially expressed genes(DEGs)were identified and 21 GO terms are commonly overrepresented.There were differential responses of different maize inbred lines subjected to drought stress at physiological and molecular levels.It could be concluded that tropical maize germplasm conferred potential resistance to water deficits as compared to the temperate maize germplasm.