Genome and transcriptome analysis of fungal secondary metabolites related to NRPS
gene family from entomopathogenic fungus, Cordyceps bassiana
Junsang Oh1,4, Min-Woo Hyun2, Jae-Gu Han1, Bhushan Shrestha1, Hyeok-Woo Kwon2,
Seong Hwan Kim2, Hyung-Kyoon Choi3, Seung Hun Yu4 and Gi-Ho Sung1,*
1
Mushroom Research Division, National Institute of Horticultural and Herbal Science, Rural
Development Administration, Suwon 441-707, Republic of Korea
2
Department of Microbiology and Institute of Basic Sciences, Dankook University, Cheonan,
330-714, Republic of Korea
3
4
College of Pharmacy, Chung-Ang University, Seoul 156-756, Republic of Korea.
Department of Agricultural Biology, Chungnam National University, Daejeon 305-764,
Republic of Korea
Cordyceps bassiana (Cordycipitaceae, Hypocreales, Ascomycota, Kingdom Fungi; asexual
stage Beauveria bassiana) is a widely distributed entomopathogenic fungus infecting a wide
range of insect hosts. A number of commercially important secondary metabolites have been
isolated from Cordyceps bassiana. In the present study, we conducted a genome data mining
for non-ribosomal peptide synthases (NRPS) that plays a crucial role in the production of
secondary metabolites (e.g., beauvericin, bassianolide, tenellin) in Cordyceps bassiana
Genome mining identified 11 NRPS and 3 NRPS-PKS hybrid gene clusters in C. bassiana. In
order to detect their expression patterns in different culture media and developmental stages,
the mycelium cultures of C. bassiana were grown in SDAY agar medium in both light and
dark conditions as well as in three different iron-, nitrogen- and lipid-rich culture media in
dark and were used for transcriptome analysis. Similarly, five different development stages of
C. bassiana stromata (ranging from stromata initial to over-matured stage) and sole mature
perithecia were tested for expression levels of NRPS by transcriptome analysis. In our results,
beauvericin synthase, a NRPS that produces beauvericin that is a representative secondary
metabolite of Cordyceps bassiana, was highly expressed at mycelium medium in dark
condition. In this study, the phylogenetic analysis of adenylation domains of NRPSs with a
sampling of Cordyceps bassiana and representative species of euascomycetes indicated that
beauvericin synthase is hypothesized to be a product of gene fusion and duplicated into
bassianolide synthase. The detailed information of expression levels of NRPSs of Cordyceps
bassiana and the phylogenetic structure of adenylation domains of NRPSs will be discussed
with a special emphasis of future research directions (e.g., target gene disruption of NRPSs
and induction of silent biosynthetic gene clusters).
*email:sung97330@gmail.com