Preliminary Analysis Of The Comparative Transcriptomes Of Thelephora Ganbajun At Different Developmental Stages

Thelephora ganbajun Zang,which mostly grows in Yunnan,has high value as an edible fungus.The huge market demand and the destruction of the habitat of Thelephora ganbajun by human activities have led to a decrease in the production of Thelephora ganbajun years by years.Most of the existing studies focus on the morphological structure,compositional analysis,taxonomic status and ecological effects of Thelephora ganbajun,but there are few studies on the genome and transcriptome of Thelephora ganbajun.The process of differentiation and formation of substrates is complex and has not been cultivated yet,and there is a lack of researches on the molecular mechanism.The differentiation and maturation of Thelephora ganbajun are genetically mediated and regulated by a variety of genes.Therefore,an in-depth understanding of the differential gene expression in different developmental stages of Thelephora ganbajun is beneficial to explore the functional genes related to the generation of Thelephora ganbajun,with a view to gaining insight into the mechanism of differentiation and development of Thelephora ganbajun at the molecular level.In this study,transcriptome sequencing was performed on samples of three growth and developmental stages of Thelephora ganbajun: mycelium,primordium,and fruiting body,and the genomic data of Thelephora ganbajun,which has been originally obtained by our group,was used as the reference genome(the genome of Thelephora ganbajun strain was sequenced by Nanopore sequencing platform,and the sequencing data showed that the total length of the genome of Thelephora ganbajun strain was 38.98 Mb,the GC content was 50.77%,the sequencing depth was 180.56 X,and the sequencing data had good quality control,which can be used as a valid reference genome for later transcriptome biomics analysis).We studied the differentially expressed genes among three growth and developmental stages(mycelium,primordium,and fruiting body)of Thelephora ganbajun,and performed functional annotation and pathway enrichment analyses of differentially expressed genes through GO database ? KOG database and KEGG database.The main results of this research are as follows:1.In order to study the expression of differential genes in the three growth and developmental stages of Thelephora ganbajun,the nutritional growth stage(mycelium)and the reproductive growth stage(primordium,and fruiting body),this study performed reference transcriptome sequencing on samples from three different developmental stages of Thelephora ganbajun(the reference genome was the genome of Thelephora ganbajun strains obtained by our group in the previous stage),obtained transcriptome data,and investigated the differential gene expression levels among samples from different growth and developmental stages of Thelephora ganbajun and the variation of expression level of differential genes between samples of different growth and development periods of Thelephora ganbajun.2.The GO?KOG function annotation and KEGG pathway enrichment analyses were performed.GO database showed that: in the developmental stage of Thelephora ganbajun from the vegetative mycelium growth to primordium(G46 vs Y)and from the vegetative mycelium growth to fruiting body(G46 vs Z),the differentially expressed genes were enriched in transmembrane transport,carbohydrate metabolism pathways and membrane components,which coordinately regulates and provides a stable internal environment for the growth and development of the primordium of Thelephora ganbajun;differential expression at the developmental stage of Thelephora ganbajun from primordium to fruiting body(Y vs Z)were mainly enriched in the ribonucleoprotein complex in the cell,indicating that the cell metabolism in the primordium stage was vigorous,and the up-regulation of ribosomal protein genes provided an important site for protein synthesis in the later stage.The results of KOG functional annotation analysis showed that during the developmental stages from the vegetative mycelium growth to primordium(G46 vs Y),and to fruiting body(G46 vs Z),the differentially expressed genes were mainly enriched in the signal transduction mechanism,which suggests that the development of Thelephora ganbajun from the vegetative mycelial morphology to primordium and fruiting body may require the initiation of certain signaling pathways to induce the formation of fruiting body;in the developmental stage from primordium to fruiting body(Y vs Z),the differentially expressed genes are mainly enriched,involving with the post-translational modification function.For most proteins,this is a post step in protein biosynthesis.The published literatures showed that such a post-translational modification played a promoting function in the morphogenesis of fungi,and the high enrichment at this stage may imply that this function is beneficial to the formation of fruit body formation.3.As a kind of ectomycorrhizal fungus symbiosed with pine trees,Thelephora ganbajun culture in vitro conditions(vegetative growth)in the laboratory could not complete its full developmental processes from the primordium and fruiting body(reproductive growth)stage.According to the enrichment of KEGG pathway,it is speculated that the MAPK pathway in the MAPK-Pheromone signaling pathway plays an important role in the morphological development of Thelephora ganbajun from the vegetative mycelia in the primordium and fruiting body,and the highly expressed Cdc42 protein in this pathway is an essential and widely expressed protein in the development of fungi;Highly expressed Ptp2,3 and Msg5 proteins participate in cell signal transduction,regulate cell growth and differentiation,and promote the development from mycelium to primordium and fruiting body.As Thelephora ganbajun can not develop into the primordium fruiting body without its associated host plants,we inferred that the MAPK signaling pathway may induce and promote the development of fruiting body of Thelephora ganbajun from the vegetative mycelia by the plant host pine tree.Previous studies on Thelephora ganbajun have mostly focused on the optimization of mycelium culture medium,the optimization of nutrient extraction process of Thelephora ganbajun,and the promotion of in situ propagation of Thelephora ganbajun.The innovation of this project lies in the transcriptome sequencing of the three growth stages of Thelephora ganbajun: mycelium,protoplasts and substrates,and the transcriptome analysis of the transcriptome data with reference information obtained by the group.To reveal the molecular mechanism of mycelium(nutritional growth)to protoplast(reproductive growth)of Thelephora ganbajun.Through transcriptome sequencing,we investigated the differential gene expression and its functions in different growth and developmental stages of Thelephora ganbajun,which can help to guide and regulate the development of zygotes at the genetic level,and provide some theoretical guidance for the artificial culture and propagation of other rare wild edible fungi based on this.Secondly,the existing models of ectomycorrhizal development may not be applicable to all ectomycorrhizal combinations,therefore,starting from the ectomycorrhizal fungus,Thelephora ganbajun,and relying on the means of transcriptome sequencing,we can study the symbiotic mechanism of Thelephora ganbajun and Pinus from the genetic level,which can enrich the research models of ectomycorrhizal symbiosis and is important for further understanding the ectomycorrhizal symbiosis and effect mechanism.