Transcriptome And Metabolome Analysis Of Rice(Oryza Sativa L.) Under Aluminum Toxicity

Rice（Oryza sativa L.）is the most widely cultivated crop in China.Aluminum（Al）toxicity is considered as one of the main factor limiting crop production in acid soil.The mechanism of Al toxicity in rice is very complex.Although some genes regulating the mechanism of Al detoxification in rice have been cloned,the mechanism of Al detoxification response in rice has not been completely elucidated.H570,the male parent of super hybrid rice Zhongzheyou 1,was determined to be Al-sensitive at seedling stage by relative root elongation（RRE）.Therefore,it is of great significance to clarify the genes expression pattern and metabolites change pattern for H570 under Al toxicity to improve its Al tolerance.In present study,transcriptome and metabolome analysis were used to analyze the differences of gene expression patterns and metabolite regulation levels of one Al-tolerant variety Nip（Nipponbare）and one Al-sensitive variety H570 after 9 days with 150μM Al Cl₃ treatment（p H=4.0）.The results are as follows:1.Nip,one recognized variety with strong Al-tolerance,was used as a positive control,and Kasalath one reported variety with sensitivity to Al toxicity,was used as a negative control to study the RRE under 150μM（p H=4.0）Al toxicity for 1 day.The results showed that the RRE of Nip,H570 and Kasalath were 0.78,0.27 and 0.32,respectively,indicating that H570 was sensitive to Al toxicity;2.After Al treatment,138 differential expressed genes and 135 differential expressed metabolites were screened in the Al-tolerant variety Nip.A total of 1298 differential expressed genes and 173 differential expressed metabolites were screened from the Al-sensitive variety H570.Venn diagram showed that there were 19 differential expressed genes and 90 differential expressed metabolites in common between the two variety.119differential expressed genes and 45 differential expressed metabolites were found in Nip,while 1279 differential expressed genes and 83 differential expressed metabolites were found in H570;3.The gene expression patterns of Al-tolerant variety Nip and Al-sensitive variety H570 were significantly different under Al toxicity treatment.Differential expressed genes included the genes relating to Protein kinase,glutathione S-transferase,UDP-glucosyltransferase,S-adenosine methionine synthase,cysteine synthase,etc.Moreover,some genes were involved in differential gene expression patterns between two variety,these genes were related to Cytochrome P450 family protein,Inorganic phosphate transporter,Amino acid transporter,Nramp（Natural drug-resistant associated macrophage proteins）family metal ion transporter,Pressure response protein,COP9 signaling body,etc;4.After Al treatment,the relative contents of differential metabolites varied significantly between two variety.The relative contents of Phenolic acid,Alkaloid,Lipid,Flavonoid,Sugar and sugar alcohol metabolites in Al-sensitive variety H570 were higher than that in Al-tolerant variety Nip.Cysteine,Alanineleucine and S-（methyl）glutathione,which had been reported previously relating to Al detoxification in rice,were significantly down-regulated in H570,but not in Nip;5.According to GO（Genetic ontology）analysis,five GO pathways include"Toxin activity（GO:0090729）","Cell death（GO:0001906）","Carbon efficiency（GO:0015976）","Biological adhesion（GO:0022610）","Cell component tissue or biosynthesis（GO:0071840）"in Al-sensitive variety H570 was specifically detected;After Al treatment,the gene expression pattern and metabolite regulation levels in“Cysteine and methionine metabolism（ko00270）”,“Starch and sucrose metabolism（ko00500）”,“Plant hormone signal transduction（ko04075）”,“MAPK（Mitogen-activated protein kinase）signaling pathway（ko04016）”were altered,and most of these genes and metabolites were specifically detected in the Al-sensitive variety H570.