Transcriptome Analysis Of Oryza.meridionalis Under Extre Me Temperature Stress By Next-generation Sequencing Technology

Oryza meridionalis belongs to the AA genome type of genus Oryza and is one of the important members of wild rice,O.meridionalis inhabits in relatively bad environment and accumulates favorable genes,which is natural germplasm repository that can be used to improve rice breeding.Up to now,few studies were reported about favorable genes of O.meridionalis.In order to discover and apply those favorable genes particularly involing in temperature stress,transcriptomes of O.meridionalis under temperature stress was analyzed in this experiment.That transcriptomes was conducted with the Illumina HiSeq 2500 platform.The main results and conclusion were as follows.Analysis on transcriptome sequence of O.meridionalis was carried out.Using the HiSeq2500(PE125),the transcriptome sequence were done with the total RNA from the control,high temperature-and low temperature-treated samples,respectively.the total 21.34 Gb of clean reads were obtained with an average of over 3.32 GB for each sample.The total 36,817 unigenes was produced by Trinity software and high correlation parameters were detected between samples,showing the results of sequence was reliable.Gene functional annotation of transcriptome was conducted.The results showed that 32,161 of 36,817 unigenes(87.35%)were well annotated in N R,GO,COG and K EGG database by blast similarity search.In addtion,4656 unigenes were detected not to be matched to any annotated genes or proteins,indicating these unigenes migtht be specific to O.meridionalis.GO analysis showed that 25,092 unigenes were assigned to the molecular function categories,cellular component and biological process.In total,10194 unigenes were annotated in the KOG database,about 5695(17.71%)unigenes were assigned to 106 KEGG pathways.Analysis on differentially-expressed genes of O.meridionalis under temperature was done.According to the FDR(False Discovery Rate)<0.01 and FC(Fold Change)≥2,a total of 2624 unigenes were detected to be differently expressed in hight temperature-stress and contained 1334 up-regulated unegenes and 1290 down-regulated unigenes.A total of 1792 unigenes were detected to be differently e xpressed in low-temperature stress and contained 1154 up-regulated unegenes and 638 down-regulated unigenes.A total of 257 unigenes were detected to both be differently expressed in hight temperature-stress and lowtemperature stress.There were 129 up-regulated unegenes in hight-temperature stress and low-temperature stress,14 unegenes were up-regulated in hight temperature stress but down-regulated in low-temperature stress.There were 84 down-regulated unegenes in hight-temperature stress and low-temperature stress.Thirty unegenes were down-regulated in hight-temperature stress but up-regulated in low-temperature stress.The differentially-expressed genes included functional genes and regulatory genes.The abundant expression were detected among functional genes,including like heat shock proteins,stress-responsive protein.Regulatory genes mainly comprised difference types of transcription factors,including MYB,bZIP,DREB,WRK Y and so on.In addition,the genes involving in phospholipid metabolism also showed different expression level.The sequence similarity were analyzed between of unigenes of O.meridionalis and the full-length cDNA of japonica,indica and Oryza rufipogon,respectively.The criteria of 80%similarity and 100 bp of pairing bases was chosen,and the results showed that the total 18357,7343 and 1913 unigenes of O.meridionalis were matched to the full-length c DNA of japonica,indica and O.rufipogon,respectively.