Transcriptome Analysis Under Heat Stress And Genome-wide Analysis Of MYB Gene Family Of A Wheat Relative Species,Brachypodium Distachyon

Heat stress greatly affects plant growth/development and the yield and quality of cereal crops.RNA-seq is a good tool to understand the dynamic changes of plants in response to heat stress.As a model plant of grasses,Brachypodium distachyon has good synteny relationship with wheat,rice,corn and sorghum.In this study,we collected the Brachypodium distachyon leaf and inflorescence at seedling and filling stage treated by high temperature and performed RNA-seq to reveal the molecular mechanism in response to heat stress.Transcription factors play key roles in response to environmental change.As one of the largest transcription factors,MYB TFs involve in plant growth and stress stimulus,but a genome-wide analysis of the MYB TFs has not yet been undertaken in Brachypodium distachyon.In this study,we identified MYB TFs at genome-wide and analyzed the expression profiles.The main results are as follows:(1)Totally,6609 DEGs were identified in the three treatments,of which 656 genes were co-differentially expressed.Function enrichment analysis of these 656 DEGs were mainly in response to high temperature and protein folding.In addition,KEGG found that antenna protein,endoplasmic reticulum and spliceosome were enriched.(2)Among 6609 DEGs,454 TFs distributed in 49 gene families were annotated.The top six types of TFs were ERF(42),bHLH(33),b ZIP(33),MYB(31),NAC(28)and WRKY(28).(3)A total of 1973 alternative splicing events in 451 DEGs were identified.Among them,Cassettes,Alternative 3' splice(A3SS),Alternative 5' splice(A5SS),Intron Retention(IR)were top four types AS events.(4)Genome-wide identification found 122 BdMYB TFs which were divided into three subfamilies,including 85 MYB-R2R3,34 MYB-related and 3 MYB-R1R2R3.Phylogenetic analysis showed that these BdMYBs have good evolutionary relationships of MYB genes in rice,Arabidopsis.(5)The gene structure and conserved motif analysis of BdMYB TFs showed that the conservation among the same subfamily.Two cis-elements were found in the promoters of BdMYB genes,one was related to the plant growth/development,and another one was related to the stress responses.Gene ontology analysis found that the BdMYB genes were involved in many biological processes.Synteny analysis showed that 56,58,61 of BdMYB genes were orthologous to rice,maize,and sorghum,respectively.(6)MYB play a key role in plant growth,development and in response to abiotic stress.Expression profile of BdMYB showed that most of them involved in flower development and abiotic stresses.