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Hoang CQ, Duong GHT, Tran MH, Vu TX, Tran TB, Pham HTN. Molecular mechanisms underlying phenotypic degeneration in Cordyceps militaris: insights from transcriptome reanalysis and osmotic stress studies. Sci Rep 2024; 14:2231. [PMID: 38278834 PMCID: PMC10817986 DOI: 10.1038/s41598-024-51946-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024] Open
Abstract
Phenotypic degeneration in Cordyceps militaris poses a significant concern for producers, yet the mechanisms underlying this phenomenon remain elusive. To address this concern, we isolated two strains that differ in their abilities to form fruiting bodies. Our observations revealed that the degenerated strain lost the capacity to develop fruiting bodies, exhibited limited radial expansion, increased spore density, and elevated intracellular glycerol levels. Transcriptome reanalysis uncovered dysregulation of genes involved in the MAPK signaling pathway in the degenerate strain. Our RT-qPCR results demonstrated reduced expression of sexual development genes, along with upregulation of genes involved in asexual sporulation, glycerol synthesis, and MAPK regulation, when compared to the wild-type strain. Additionally, we discovered that osmotic stress reduced radial growth but increased conidia sporulation and glycerol accumulation in all strains. Furthermore, hyperosmotic stress inhibited fruiting body formation in all neutralized strains. These findings indicate dysregulation of the MAPK signaling pathway, the possibility of the activation of the high-osmolarity glycerol and spore formation modules, as well as the downregulation of the pheromone response and filamentous growth cascades in the degenerate strain. Overall, our study sheds light on the mechanisms underlying Cordyceps militaris degeneration and identifies potential targets for improving cultivation practices.
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Affiliation(s)
- Chinh Q Hoang
- Center of Experimental Biology, National Center for Technical Progress, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Vietnam.
| | - Giang H T Duong
- Center of Experimental Biology, National Center for Technical Progress, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Vietnam
- Department of Molecular Biotechnology, Institute of New Technology, Academy of Military Science and Technology, 17 Hoang Sam, Cau Giay, Hanoi, Vietnam
| | - Mai H Tran
- Center for Biomedical Informatics, Vingroup Big Data Institute, and GeneStory JSC, 458 Minh Khai, Hai Ba Trung, Hanoi, Vietnam
- GeneStory JSC, 458 Minh Khai, Hai Ba Trung, Hanoi, Vietnam
| | - Tao X Vu
- Center of Experimental Biology, National Center for Technical Progress, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Vietnam
| | - Tram B Tran
- Center of Experimental Biology, National Center for Technical Progress, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Vietnam
| | - Hang T N Pham
- Department of Pharmacology and Biochemistry, National Institute of Medicinal Materials, 3B Quang Trung, Hoan Kiem District, Hanoi, 100000, Vietnam
- University of Medicine and Pharmacy, Vietnam National University, 144 Xuan Thuy, Cau Giay District, Hanoi, 100000, Vietnam
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Distinct Roles of Two DNA Methyltransferases from Cryphonectria parasitica in Fungal Virulence, Responses to Hypovirus Infection, and Viral Clearance. mBio 2021; 12:mBio.02890-20. [PMID: 33563819 PMCID: PMC8545091 DOI: 10.1128/mbio.02890-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Two DNA methyltransferase (DNMTase) genes from Cryphonectria parasitica have been previously identified as CpDmt1 and CpDmt2, which are orthologous to rid and dim-2 of Neurospora crassa, respectively. While global changes in DNA methylation have been associated with fungal sectorization and CpDmt1 but not CpDmt2 has been implicated in the sporadic sectorization, the present study continues to investigate the biological functions of both DNMTase genes. Transcription of both DNMTases is regulated in response to infection with the Cryphonectria hypovirus 1 (CHV1-EP713). CpDmt1 is upregulated and CpDmt2 is downregulated by CHV1 infection. Conidium production and response to heat stress are affected only by mutation of CpDmt1, not by CpDmt2 mutation. Significant changes in virulence are observed in opposite directions; i.e., the CpDmt1-null mutant is hypervirulent, while the CpDmt2-null mutant is hypovirulent. Compared to the CHV1-infected wild type, CHV1-transferred single and double mutants show severe growth retardation: the colony size is less than 10% that of the parental virus-free null mutants, and their titers of transferred CHV1 are higher than that of the wild type, implying that no defect in viral replication occurs. However, as cultivation proceeds, spontaneous viral clearance is observed in hypovirus-infected colonies of the null mutants, which has never been reported in this fungus-virus interaction. This study demonstrates that both DNMTases are significant factors in fungal development and virulence. Each fungal DNMTase affects fungal biology in both common and separate ways. In addition, both genes are essential to the antiviral responses, including viral clearance which depends on their mutations.
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