长日照条件下2个热带玉米自交系的转录组差异分析

Analysis of transcriptome differences between two tropical maize inbred lines planted under long sunshine

  • 摘要: 【目的】深度挖掘不同光敏类型自交系间的差异表达基因,为揭示热带玉米种质光周期敏感性变异机理提供理论依据,同时为采用分子辅助方法改良热带玉米种质提供新途径。【方法】以热带光钝感自交系QR273和光敏感自交系T32为试验材料,通过人工控制长日照条件(16 h光/8 h暗)对试验材料进行处理,于四叶期采集幼嫩叶片提取总RNA,利用RNA-Seq技术对不同光敏类型自交系材料进行转录组测序,同时结合生物信息学分析,筛选出不同光敏类型自交系间的差异表达基因。【结果】在长日照条件下,从玉米自交系T32和QR273间共鉴定出6977个差异表达基因,其中T32较QR273的上调表达基因有3291个、下调表达基因有3686个。GO功能注释分析结果显示,有24个应答光刺激和应答辐射的基因在T32和QR273中表现出显著差异;此外,有17个同时与应答光刺激、应答辐射、胚后期发育、光周期、生殖结构发育、生殖系统发育、生殖发育过程、光周期/开花和分生组织营养生长向生殖生长转变相关的差异表达基因。KEGG信号通路富集分析发现有15个昼夜节律通路相关基因在T32和QR273中表现出显著差异,其中,Zm00001e030377和Zm00001e023792基因在T32中的表达量高于QR273,而Zm00001e016746和Zm00001e011193基因在T32中的表达量低于QR273。【结论】长日照条件下光敏型与光钝型热带玉米自交系间的转录组差异分析共鉴定出6977个显著差异表达基因,包括24个参与应答光刺激和应答辐射的差异表达基因有,17个同时与应答光刺激、应答辐射、胚后期发育、光周期及分生组织营养生长向生殖生长转变相关的差异表达基因,以及15个与昼夜节律通路相关的差异表达基因。这些基因通过差异性参与昼夜节律通路中的成花诱导,导致成花启动途径不完全相同,可能是热带种质光周期敏感性变异的关键遗传基因。

     

    Abstract: 【Objective】The differentially expressed genes(DEGs)among different photosensitive inbred lines were explored,so as to provide a theoretical basis for revealing the variation mechanism of photoperiod sensitivity of tropical maize germplasm and a new way of improving tropical maize germplasm by molecular assisted method.【Method】 Tropical germplasm light-insensitive inbred lines of QR273 and light-sensitive inbred line of T32 were used as test materials, which were planted under artificial control conditions of long-days(LD)treatment(16 h light/8 h dark). In the four leaf stage,young leaves were gathered,and their total RNA was extracted. The transcriptome sequencing of different photosensitive inbred lines was carried out by RNA-Seq technology. At the same time,combined with bioinformatics analysis,the DEGs among different photosensitive inbred lines were screened.【Result】Under LD conditions,a total of 6977 genes showed differentially expression between lines of T32 and QR273,of which 3291 genes showed up-regulated expression in T32 and 3686 genes showed downregulated expression in T32. GO functional annotation analysis showed that 24 genes responding to light stimulation and radiation showed significant differences in T32 and QR273 and that there were 17 DEGs related to response to light stimulation and radiation, post embryonic development,photoperiod,reproductive structure development,reproductive system development,reproductive development process,photoperiod or flowering and meristem vegetative to reproductive growth. Enrichment analysis of KEGG signaling pathway showed genes related to circadian rhythm pathway had significant differences in expression between T32 and QR273. The expression of Zm00001e030377 and Zm00001e023792 genes in T32 was higher than that in QR273,while the expression of Zm00001e016746 and Zm00001e011193 genes in T32 was lower than that in QR273.【Conclusion】 A total of 6977 DEGs are identified by transcriptome difference analysis between photo-sensitive and light-insensitive tropical maize inbred lines under long sunshine conditions,of which 24 DEGs involved in response to light stimulation and radiation,and 17 DEGs related to response to light stimulation,radiation,post embryonic development,photoperiod and the transformation from vegetative growth to reproductive growth of meristem,and 15 DEGs related to circadian rhythm pathway. These genes may be the genetic factors leading to the significant differences in photoperiod sensitivity variation among tropical maize germplasms.

     

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