Transcriptomic Analysis On The Inhibition Of Light On The Growth Of Villosiclava Virens Mycelia And Cloning Of Its Light Receptor Gene

With increasing incidence in recent years,rice false smut has become one of the major rice diseases from a minor one.Rice false smut causes such problems as rice yield reduction,rice quality decrease and production of toxins harmful to humans and animals,which has made its pathogen Villosiclava virens a research hot spot.Experiments showed that light could significantly inhibit the growth of V.virens mycelia,but there is no relevant report about the involved mechanisms.In this study,V.virens(strain ZJ09)were cultured under dark and white light conditions respectively.The mycelia of both groups were collected and conducted RNA-seq by Illumina high-throughput sequencing techniques.The gene expressions of the two groups of V.virens samples were compared and 695 differentially expressed genes(DEGs)were identified,among which 359 were up-regulated and 336 were down-regulated.Six DEGs were selected to check by qRT-PCR and the expression results were consistent with those by RNA-seq,suggesting the data were credible and effective.During GO(Gene Ontology)enrichment analysis 491 of the 695 DEGs were enriched to the terms of biological process,cellular component or molecular function,indicating that complex mechanisms may be involved in the inhibitory effect of light on the growth of V.virens mycelia.KEGG(Kyoto Encyclopedia of Genes and Genomes)pathway analysis results of the 695 DEGs indicated that influences on the structure and functions of ribosome,and amino acid metabolism were quite probably involved in the inhibitory effect of light on the growth of V.virens.Specific analysis of the functions of some important DEGs showed that light significantly affected the expressions of an acetyl-CoA synthase gene,some MAPK signaling pathway-related genes,some cell division-related genes,and some pathogenicity-related genes of V.virens.These genes had been proved to play important roles in the development of many other species of fungi.However,the expression level of the gene UvHOG1,which had been reported to be related with the growth of V.virens mycelia,was not affected by light.Further V.virens mycelia experiments with treatment by different lights confirmed that both blue and red lights had inhibitory effect on the mycelia growth of this fungus.The inhibitory effect of blue light was much stronger than that of red light.The coding sequences of the gene of the blue light receptor,White Collar-1,of V.virens strain ZJ09 was cloned.Results of bioinformatics analysis showed that its encoded White Collar-1 had photosensitive domains and had the closest evolutionary relationship with White Collar-1 of the fungi Metarhizium.The results of this study provide helps for understanding how light regulates the growth of V.virens mycelia at the molecular level.