玉米自交系籽粒响应高温胁迫的转录组分析

Kernel Transcriptome Analysis of Maize Inbred Lines in Response to High Temperature Stress

玉米籽粒发育时期对高温胁迫十分敏感,严重影响玉米的产量和品质。为研究不同耐高温玉米自交系籽粒响应高温胁迫的基因表达差异,在基因水平解析不同玉米种质响应高温胁迫的分子机制,以前期筛选的耐高温自交系XN202和敏感自交系CT110为材料,利用RNA-Seq技术挖掘正常和高温胁迫下授粉后15 d玉米籽粒的差异表达基因(DEG)。与对照相比,XN202和CT110分别检测到1517,1012个DEGs,共同的DEGs有142个,包含7个转录因子。不同耐高温玉米自交系的籽粒对高温胁迫的响应存在明显差异,通过基因本体(GO)功能注释和全基因组及代谢途径数据库(KEGG)信号通路富集分析筛选出DNA复制、核小体、微小染色体维持复合物、DNA引物酶-多聚酶α复合体、营养库活性、丙氨酸、天冬氨酸和谷氨酸代谢等共同参与响应高温胁迫的应答过程。通过生物信息学分析,共有374个DEGs位于已报道的玉米耐高温相关性状QTL区间,其中42个DEGs为已报道的耐高温相关基因。综上所述,高温胁迫下玉米籽粒会形成复杂的细胞保护和防御系统,AP2/ERF、MYB、bHLH、NAC、HSF、HSP等耐高温相关的DEGs可能在分子调控网络中发挥重要作用。

Maize grain development stage is very sensitive to high temperature stress,which seriously affects the yield and quality of maize.To study the difference of gene expression in grain and analyze the gene molecular mechanism of different high-temperature tolerant maize inbred lines in response to high-temperature stress,RNA-Seq technology was used to analysis the differentially expressed genes(DEGs)of XN202(heat tolerant)and CT110(heat susceptible)in maize grains 15 days after pollination under normal and high temperature stress.Compared with the control,XN202 and CT110 detected 1517 and 1012 DEGs,respectively,with 142 common DEGs,including 7 transcription factors.There were significant differences in grain response to high temperature stress among different heat tolerant inbred lines.DNA replication,nucleosome,minichromosome maintenance complex,alpha DNA polymerase:primase complex,nutrient reservoir activity,alanine,aspartate and glutamate metabolism were involved in response to high temperature stress through gene ontology(GO)function annotation and kyoto encyclopedia of genes and genomes(KEGG)signal pathway enrichment analysis.According to bioinformatics analysis,a total of 374 DEGs were located in the reported QTL interval of heat tolerance related traits in maize,and 42 DEGs were putative heat tolerance candidate genes.In summary,maize grains could form complex cellular protection and defense system under high temperature stress,and DEGs related to high temperature tolerance,such as AP2/ERF,MYB,bHLH,NAC,HSF and HSP,might play an important role in the molecular regulatory network.