Transcriptome Profile Of Faba Bean During Seed Germination Under Salt Stress And Analysis Of LEA Gene Family

Faba bean(Vicia faba L.)is an important food legume crop.Salinity soils severely constrain the production of faba bean,however,the seed germination of faba bean,which is a vital plant growth stage,is sensitive to salinity.Planting improved varieties of faba bean,which exhibit salt tolerance in seed germination stage,is an optimal strategy for faba bean product.To investigate the genes dynamics during the seed germination stage under salinity,RNA-seq method was used to investigate genome-wide transcription profiles of two faba bean varieties with contrast salt-tolerance during the seed germination.A total of 4,486 differentially expressed genes(DEGs)were identified among the comparison of salt-tolerant variety Y134 and saltsensitive variety Y078 treated with salinity or not.Of these,1,410 candidate DEGs were identified as salt-stress response genes.Furthermore,623 DEGs were identified as variety-specific response gene during seed germination at 16 h or 24 h with salt treatment.These DEGs involving in cell wall loosening(e.g.,xyloglucan endotransglucosylase/hydrolase,chitinase,and expansin),hormone metabolism(e.g.,LEA genes,genes associated with ABA or ethylene signal pathway),chromatin remodeling(e.g.,chromatin structure proteins,LHP1),small interfering RNA pathway,etc.,were significantly up-regulated in salt-tolerance variety with salt treatment,indicating that they play critical roles in regulation of seed germination.Meanwhile,some transcription factors were also identified.The results show that a large number of genes can regulate the response of broad beans to salt.According to the transcriptome(RNA-seq)data of broad bean seeds during the germination period under salt stress,online databases(NR,Swiss-prot,and PFAM 3)were used to screen and annotate LEA-related genes of broad bean.Conservative Sequence Analysis of Broad Bean LEA Gene by NCBI’s CDD Excludes Unrelated Genes,the physical and chemical properties of the protein were analyzed using Ex PASy and GSDS online software,and the system evolution analysis and protein motif analysis were performed using MEGA-X and MEME.Based on the analysis of salt stress transcriptome data,the LEA gene differential expression pat-terns in faba beans(Y134 salt tolerance and Y078 salt tolerance)were analyzed at two different treatment times,and three genes that could affect seed germination under salt stress were found.These findings help to improve people’s understanding of the salt tolerance mechanism during seed germination and provide valuable genetic resources for future breeding of salt-tolerant broad bean varieties.