转录组测序解析超级稻淮稻5号灌浆速率快的机理

Deciphering the Functional Mechanism of Fast Grain Filling Rate in a Super Rice Huaidao 5 by Transcriptome Analysis

灌浆速率是水稻重要而复杂的农艺性状之一,直接影响产量和品质。淮稻5号是由7208×武育粳3号杂交后代选育而成的粳稻优良品种,具有较高的灌浆速率,但其重要的分子特征尚不清楚。对淮稻5号和武育粳3号受精后14 d的种子提取RNA进行转录组分析。采用实时荧光定量PCR分析籽粒灌浆速率相关基因的表达水平,采用Sanger测序法分析淮稻5号和武育粳3号中已克隆的灌浆速率相关基因序列差异。在淮稻5号和武育粳3号之间检测到3230个上调基因和1171个下调基因。GO富集分析表明,这些基因主要参与淀粉和蔗糖生物合成、光合作用、碳同化、激素生物合成和信号转导途径。与武育粳3号相比,淮稻5号激活了较多参与淀粉和蔗糖生物合成的基因。共检测到63个激素相关差异表达基因,其中38个基因参与生长素途径,表明生长素在水稻籽粒灌浆过程中起着重要作用。一些已知的灌浆速率相关基因(GFR1、OsPFP1、OsPHO1;2、OsSWEET13、OsCIN2)在淮稻5号中显著上调。Sanger测序表明GFR1Huaidao5可能是控制灌浆速率的优异单倍型。

Grain filling rate is an important and complex agronomic trait that directly affects rice yield and quality.Huaidao 5,a superior rice japonica variety,derived from the 7208×Wuyujing 3 cross,shows a high grain filling rate,whereas its functional mechanism remains unclear.A transcriptome analysis in Huaidao 5 and Wuyujing 3 was performed by harvesting 14-days-after-fertilization grains.Real time fluorescent quantitative PCR was used to analyze the transcripts of few candidate genes,and Sanger sequencing was applied to identify their polymorphisms between Huaidao 5 and Wuyujing 3.3230 up-regulated and 1171 down-regulated genes were detected between Huaidao 5 and Wuyujing 3.Gene ontology analysis indicated that these differentiallyexpressed genes were primarily involved in starch and sucrose biosynthesis,photosynthesis,carbon assimilation,and hormone biosynthesis and signaling transduction pathway.If compared to Wuyujing 3,more genes involved in starch and sucrose biosynthesis were up-regulated in Huaidao 5.Sixty-three hormone-related differentially expressed genes were detected,of which 38 genes were involved in the auxin pathway,suggesting that auxin plays an important role in the rice grain filling process.Several identified grain-filling-rate-related genes(GFR1,OsPFP1,OsPHO1;2,OsSWEET13,OsCIN2)were significantly up-regulated in Huaidao 5.Moreover,Sanger sequencing showed that GFR1Huaidao5 might be an excellent haplotype to control the grain filling rate.