The Function Of Upstream Regulatory Genes In The Spore-producing Pathway Of Porphyridium Violaceum And The Interaction Transcriptomics Study Of C.elegans Infection

Purpureocillium lavendulum is an important nematode biocontrol fungus.When the fungus infects the host,the amount of conidia directly affects its infection efficiency.In order to study the spore-forming regulatory pathways,the whole genome of P.lavendulum was searched by BLASTP,and the possible upstream sporulation-regulated genes were determined and knocked out.After that,the phenotypes related to the sporulation of the knockout strains were studied,and the functions of upstream genes related to the sporeforming regulation of P.lavendulum were preliminarily established,which laid a foundation for the study of the regulation mechanism of the spore production by P.lavendulum.In addition,it was found that the killing of P.lavendulum to Caenorhabditis elegans is a long-term process.In order to study the interaction between P.lavendulum in the process of fungus-nematode interaction,the transcriptome analysis was performed on two different stages of invasion of C.elegans by P.lavendulum to further understand which virulence factors were released during the infection of the intestine tissues of C.elegans.At the same time,the molecular mechanism of the defense in the intestine of the nematode is identified.A deep understanding of the fungal-nematode interaction mechanism will lay the foundation for the construction of a safe and efficient nematode biocontrol agent.The main results of this study:1.Knockout of upstream activators of conidiationKnockout vector was constructed by using the chlorimuron resistance gene(sur)as a screening marker,transformed by Agrobacterium tumefaciens and knocked out by homologous recombination.Five mutants of ?flu G?1,?flu G?2,?flb A,?flb C,?flb D and double mutants?flu G?1?flu G?2 were successfully obtained.As a result,it was found that the growth of ?flb A mycelium was dense and sporulation was significantly reduced.After a certain period of time,the whole colony was autolyzed;The sporulation of the ?flu G?2 strain was delayed but did not affect the spore production;?flu G?1 strains,?flb C strains and ?flb D strains of vegetative growth is restrained,but spore production will increase;?flu G?1 ?flu G?2 double mutant strains vegetative growth and ?flu G?2 strains are consistent,but the amount of spore production fell by almost a third.2.Samples from two different stages of infection with C.elegans were successfully collected.18 samples were subjected to transcriptome sequencing and differential expression analysis using RNA-Seq technology,and DAF-2 insulin/IGF-I like signaling pathway,p38 MAPK pathway,TGF-? pathway and other classic innate immune pathway of C.elegans had significant changes in the response to the infection of P.lavendulum.The main innovations of this paperFor the first time,the function of the upstream activators of conidiation of P.lavendulum was studied.The interaction between the P.lavendulum and C.elegans was studied for the first time.It was a new mechanism for researching for fungal infection nematodes and a new nematode immunization.The study laid the foundation for researching new mechanism of fungal infection and nematode immunization,as well as construction of an efficient and safe nematode biocontrol agent.