Transcriptome Profiling Of Aegilops Tauschii Leaves By Jasmonate Treatments And Characterization Of JAZ Family Genes

Aegilops tauschii,(2n = 14,DD),the D-genome progenitor of common wheat(2n = 42,AABBDD),provides valuable genetic resources for biotic and abiotic stress resistance in wheat.Aegilops tauschii carries a large number of genes improving adaptability during wheat modern breeding.Thus,Aegilops tauschii is essential in wheat germplasm resource creation.With the development of genetics and genomics,Aegilops tauschii is considered to be important for studying the function of unknown genes in wheat and molecular evolution of Triticum.Jasmonic acid(JA)is an important plant hormone derived from lipid and its biological activity.The derivative JAs mediate plant resistance to insects.It also plays an important role in the regulation of vegetative reproduction,cell cycle regulation and senescence.In order to explore the expression profile of JA-responsive genes in Aegilops tauschii,we treated the 12-days old seedlings of Aegilops tauschii with 5 mM JA solution.After applying JA for one hour and six hours respectively,the shoots were sampled,sequenced and analyzed by a bioinformatics pipeline.The gene expression profile was constructed and the gene family analysis of the marker gene JAZs of JA signaling pathway was carried out.The main results are as follows:1.We identified 22112 transcriptional units by RNA-seq,of which 3078 genes were differentially expressed and about 50% of the differentially expressed genes were unannotated.In order to infer the function of the genes,we constructed an annotation pipeline.The differentially annotated genes were analyzed by GO enrichment,which were mainly concentrated in the terms of response to external stimulation,response to jasmonic acid stimulation,and redox reaction.The genes induced by jasmonic acid were divided into four categories.The first type of genes are those that were induced after one-hour and recovered after six hours.We define them as transiently induced genes(TIG).The second type were defined as transiently repressed genes(TRG)that were induced at one-hour and continued to be induced at six-hour.And the third type were defined as sustainedly induced genes(SIG)that were induced at one-hour and continue to be induced at six-hour.Other genes belong to the fourth type were these genes that are sustainedly repressed genes(SRG).According to the above information,the gene expression profile induced by jasmonic acid is constructed for key signaling genes.2.The JAZ(Jasmonate ZIM-domain)genes are important genes in the jasmonic acid signaling pathway.The JAZ genes were identified by homology search.Phylogenetic analysis was performed with the identified JAZ genes in Arabidopsis thaliana,rice,and Brachypodium distachyon and tissue differential expression was analyzed.It was found that AetJAZ5 and AetJAZ8 were clustered into one small group with AetJAZ6 and AetJAZ7,forming a second group and the two groups are related with each other,without homologous genes in other species.It was found that AetJAZ6 and AetJAZ7 were not expressed in any tissues studied.It was suggested that there were two possible types of JAZ gene expression patterns in the signal pathway of jasmonic acid,namely: AetJAZ6 and AetJAZ7,respectively.These two genes may have been pseudogenized after replication.JAZ genes showed tissue-specific and space-specific expression patterns.This work provides important insights into the JA signaling in the wheat progenitor Ae.tauschii.