Rejuvenation Of Entomogenous Fungus Of Isaria Fumosorosea And Differential Expression Analysis Of Virulence Related Genes

Isaria fumosorosea Wize as an essential entomogenous fungi,plays a huge role in biological control.However,with the increase of the number of subcultures,the strains degenerate obviously,which is reflected by reducing conidial production capacity and the decrease of virulence.In this thesis,the strain was rejuvenated by adding different nutrients to medium,and the degraded and rejuvenated strains were sequenced by high-throughput sequencing technology.The results of the study are as following:1.The virulence recovery of the strain was the best after rejuvenation with chitin medium.At the 10 th generation,the LT₅₀ decreased from 5.86 d to 3.32 d of the original strain.The Plutella xylophone larvae had a corrected mortality higher than 82% on the 7th day,and the recovery ratio was stable;the conidia production of the strain recovered best after rejuvenation of the silkworm chrysalis medium,which increased from 4.28×106 conidia/cm2 to 1.73×107 conidia/cm2 of the original strain,which increased by 4times,but the recovery of virulence was poor;the comprehensive medium had both virulence and conidia production good recovery effect and stable recovery ratio,the 10 th generation LT50 was 3.53 d and conidia production was 1.58×107 conidia/cm2.2.After transcriptome sequencing,a total of 46.29 Gb Clean Data was obtained.The Q30 base percentage was greater than 93.17%,the GC content was between 56.86-60.52%,and the number of N50 was 1436.66,912 Unigenes were assembled,and 54,273 annotations were obtained,accounting for 81.11%of the total Unigenes.3.773 differentially expressed genes were screened from the sequencing results,of which 747 were up-regulated and 26 were down-regulated.The COG classification and annotations are the most common for translation,ribosomal structure and biosynthesis,protein transport,protein chaperones,and carbohydrate transport and metabolism;Perform GO enrichment analysis and annotate into 48 GO terms,mainly focusing on metabolic processes and cellular processes;For KEGG pathway annotation,the genetic information processing category accounts for the largest proportion（43.19%）,and the most annotated pathways are: ribosomes,antibiotic biosynthesis and sugar metabolism.In addition,10 DEGs were selected and verified by q RT-PCR,and the results were consistent with the results of transcriptome sequencing,which confirmed the credibility and validity of the transcriptome data.4.Among all the DEGs,annotate 30 up-regulated genes related to protease and the difference is between 2.0-4.2 times and 3 pr1 genes are among them;annotate 2 chitinase-related up-regulated genes,increased by 4.5 times and 3.3 times respectively.In addition,some genes that affect pathogenicity,such as MAPK and MPL-1,are equally up-regulated.