Study On Genomics Of Cordyceps Farinosa And Its Related Species

Cordyceps farinosa,Cordyceps fumosorosea and Cordyceps cateniannulata were all entomopathogenic fungi with related phylogenetic relationship.The research on these three Cordyceps fungi mainly focused on biological control,drug development and biotransformation,and the corresponding research results had been achieved.However,the molecular mechanism of their biological function were rarely reported.It was of great significance for the development and application of these three Cordyceps fungi to explore and compare genes function through genomics research.In this study,phylogenetic analysis showed that C.farinosa,C.fumosorosea and C.cateniannulata were closely related.Then,the mitochondrial genome and the whole genome were assembled and annotated,the gene structure and function of the three Cordyceps fungi genomes were compared.The results showed that the mitochondrial genome size was about 30 Kbp,the genome size was more than 30 Mbp,and there were a lot of nucleotide variations among genome sequences,including single nucleotide variation and short insertion and deletion.The same point was that their mitochondrial genomes all contained 25 t RNA genes,ribosomal RNA small subunit genes,ribosomal RNA major subunit genes,ribosomal protein S3 genes and 14 core protein coding genes,and the arrangement of genes was consistent,only the number of introns and ORF was different,which revealed that the gene structure and gene function of mitochondrial genome were highly conserved.The whole genome of C.farinosa,C.fumosorosea and C.cateniannulata contained 11030,10263 and 10093 protein coding genes respectively by gene structure prediction,the classification and comparison results of gene function,metabolic pathway,enzyme function and secondary metabolite were as follows.The common feature of COG first-class classification was that most genes function were related to metabolism,taking up more than 40%;secondly,genes involved in cell process and signal transmission,accounting for 30%;and about 20% of genes were related to information storage and processing.The secondary classification of COG had a similar frequency distribution,among which the most frequent genes function was related to post translation modification,protein conversion and molecular chaperone,and then functional genes related to carbohydrate transport and metabolism.In addition,the related functional genes involved in the transport and metabolism of amino acids,intracellular transport,secretion and vesicle transport,and the biosynthesis,transportation and decomposition metabolism of secondary metabolites also accounted for a large proportion.The GO secondary classification frequency of genes function of C.farinosa,C.fumosorosea and C.cateniannulata was similar,these genes were mainly involved in biological process as cell process,metabolism process,biological regulation,localization and stress,and molecular function as catalytic activity and molecular binding.The proportion of metabolic pathways in KEGG pathway first-class classification was similar,among which metabolism had the largest proportion,followed by human diseases.The KEGG pathway secondary classification had a similar frequency distribution,their common features were active amino acid metabolism and carbohydrate metabolism,and signal transmission in environmental information processing also accounted for a large proportion,indicating that their growth process and environmental information had a close interaction.In the metabolic pathway related to human diseases,infectious diseases,cancer,neurodegenerative diseases,endocrine and metabolic diseases,antineoplastic antimicrobial,substance dependence,cardiovascular diseases and immune diseases also had annotated functional genes,indicating that these three Cordyceps fungi may contain metabolites related to human diseases.The results of functional enzyme in EC classification showed that the proportion of oxidoreductase,transferase and hydrolase was the largest,reaching more than 80%.In addition,the carbohydrates active enzymes obtained by CAZy annotation,most of them belonged to glucoside hydrolase and glycosyltransferase,taking up more than 90%.More than 30 gene clusters of secondary metabolites were identified in the genomes of C.farinosa,C.fumosorosea and C.cateniannulata.Among these secondary metabolite gene clusters,9,7 and 9 were known.Among the known secondary metabolites,these three Cordyceps fungi had both common and unique.It had been proved that these secondary metabolites exhibited biological activities such as fungal toxicity,antibacteria l,antiviral,anti-tumor,neuroprotection and cholesterol reduction.In conclusion,the phylogenetic relationship among C.farinosa,C.fumosorosea and C.cateniannulata was related,and was belonged to the related species in the phylogenetic tree.There were many differences among their genome sequences,such as sequence length,nucleotide variation and gene number,but the classification frequency of genes function was similar,which may be the basis for them to have similar biological function.Secondary metabolites with known function had been proved to have a wide range of biological and pharmacological activities,which may be used in biological control and drug development.Most of the secondary metabolite gene clusters had not yet been identified,which may indicate that these three Cordyceps fungi still had potential development and application value.