普通野生稻种子萌发的转录组动态研究

Transcriptome Dynamics of Seed Germination of Oryza rufipogon Griff

普通野生稻是亚洲栽培稻的祖先种,对其种子萌发过程的解析对野生稻资源的挖掘利用有重要促进作用。本研究在表型分析基础上利用转录组测序技术,对吸胀后0h、2h、4h、6h、8h、10h和12h的普通野生稻种子表达基因进行检测,并与栽培稻转录组数据进行比较分析。研究发现普通野生稻种子萌发过程中有11853个差异表达基因(Fold change≥2.0)。表达模式可分为5种类型,其中一组在快速吸涨期(PhaseⅠ)到吸涨滞缓期(PhaseⅡ)为独特的瞬时表达模式,并富含转录因子(占该组基因的10.33%)。和栽培稻种子表达基因比较结果表明,植物同源结构域(PHD)和热休克因子(HSF)家族基因在普通野生稻中延后表达,其中5个表达模式不同的HSF家族基因在普通野生稻中得到qRT-PCR验证。进一步分析发现HSF基因通过热激元件(HSE)顺式调控32个差异表达基因的表达,推测它们在普通野生稻种子萌发过程中发挥重要作用。本研究初步明确了普通野生稻种子萌发过程的差异表达基因及转录因子,它们可作为野生稻优异基因利用的参考资源。

Oryza rufipogon Griff.is the ancestor of Asian cultivated rice O.sativa.The analysis of molecular dynamics during seed germination provides insights into the mechanism underlying seed germination and implications for utilization of wild rice resources.In this study,we used transcriptome sequencing technology to examine the dynamics of gene expression of O.rufipogon seeds at 0h,2h,4h,6h,8h,10h and 12h after imbibition,and compared them with that of O.sativa.A total of 11853 differentially expressed genes(DEGs)(Fold change≥2.0)was found during the seed germination of O.rufipogon.Those DEGs could be divided into 5 groups regarding to their expression patterns,of which,one group displayed an unique transient expression during the period between rapid imbibition(PhaseⅠ)to imbibition stagnation(PhaseⅡ),including rich transcription factors that accounted for 10.33%of the genes in this group.Compared with O.sativa.,the PHD(plant homeodomain)and HSF family genes showed significant delayed expression in O.rufipogon,and from which,five HSF family genes with delayed expression were verified by qt-PCR.Further analysis revealed that HSF gene cis-regulated the expression of 32 DEGs through heat shock element(HSE),indicating their important role in governing the seed germination of O.rufipogon.The DEGs identified here can be as genetic resources for the utilization of O.rufipogon in rice improvement.