Salt Tolerence Identification Of Jute (Corchorus Olitorius L.) Germplasm And Transcriptome Analysis

Jute was an important cash crop which can be planted in coast areas and saline and alkaline soil.And it was also the critical raw materials for bast fiber industry.Its yield and planting area were only inferior to cotton in the world.But there were few reports on jute salt resistance research.By evaluating the salt tolerance of 50 jute germplasm resources,two extreme materials on salt tolerance were screened and the transcriptome analyses of them was finished in this study,with the hope of providing a reference for jute salt tolerance evaluation and genetic resources for jute salt tolerant breeding,and finding some salt stress related genes.The main results are as follows:1.In this study,50 jute materials were cultured with hydroponics supplemented with NaCl at different concentrations of 0,250mmol/L,repectively.Then the salt injury index after treatment and death rate on the eighth day（DR）of 50 materials were investigated.Salt injury index at 5th day（SI5）,salt injury index at 8th day（SI8）and DR showed significant differences among different germplasm materials.The results showed that highly significant differences were existed among different jute germplasm resources,and 250 mmol/L NaCl was demonstrated a suitable concentration for screening salt tolerant materials in this experiment.2.The regression equation models reflecting the correlation between stressed duration and salt injury index of jute materials were established,in order to get the time when the symptom of salt damage appeared and salt injury index up to 50%.And 50 jute germplasm resources were evaluated for salt tolerance and classified by principle components analysis,subordination function method and hierarchical cluster analysis.Based on the comprehensive ability of salt tolerance of materials and cluster analysis,50 jute germplasm resources could be classified into 4 grades.3 materials were highly salt tolerant,6 materials were salt tolerant,10 materials were salt sensitive,and 31 materials were middle tolerant.3.This study used high-throughput sequencing technologies(Illumina HiSeq^TM2000/MiSeq^TM)to study the leaf and root of TC008-41 and NY/252C under control and 250 mmol/L NaCl（at 12h after treatment）.Based on the RNA-seq,we generated 68961 Unigenes.And the unigene lengths varied between 201 and 15890 nucleotides with the average lengths 1322bp.55080（79.87%）unigenes were successfully annotated in seven databases,include NR（non-redundant database;NCBI）,NT（nucleotide collection database;NCBI）,KO（Kegg Orthology）,GO（Gene Ontology）,KOG（Eukaryotic Orthologous Groups）,Pfam,and SwissProt.We identified 2372 TFs from 79 families,and 385 of them（representing 56 families）differentially expressed under salt stress.4.According to the Gene Ontology analysis of differentially expressed genes（DEGs）,524/777,1293/4041,270/129 and 452/2574 upregulated/downregulated genes were found in NYL（the leaves of NY/252C）,NYR（the roots of NY/252C）,TCL（the leaves of TC008-41）and TCR（the roots of TC008-41）.On the basis of Encyclopedia of Genes and Genomes（KEGG）enrichment analyses,the DEGs of NY/252C were significantly enriched in plant hormone signal transduction,ribosome,the regulation of autophagy,plant-pathogen interaction and galactose metabolism.The DEGs of TC008-41were enriched in ribosome,plant hormone signal transduction and oxidative phosphorylation.5.A real-time quantitative PCR（RT-qPCR）analysis was performed to validate the expression profiles with eleven randomly selected DEGs.Nearly all the eleven DEGs displayed similar expression patterns to those generated from high-throughput sequencing.In this way,the reliablity of the high-throughput sequencing was verified.