Asphyxiation of Metarhizium robertsii during mycelial growth produces conidia with increased stress tolerance via increased expression of stress-related genes

Author(s)

Silva, Albery M. ; Pedrini, Nicolas ; Pupin, Breno ; Roberts, Donald W. ; Rangel, Drauzio E. N.

• Document type: Journal article
• Source: FUNGAL BIOLOGY; v. 127, n. 7-8, p. 9-pg., 2023-07-01.

Abstract

Little is known about the impact of hypoxia and anoxia during mycelial growth on tolerance to different stress conditions of developing fungal conidia. Conidia of the insect-pathogenic fungus Metarhizium robertsii were produced on potato dextrose agar (PDA) medium under normoxia (control 1/4 normal oxygen concentrations), continuous hypoxia, and transient anoxia, as well as minimal medium under normoxia. The tolerance of the conidia produced under these different conditions was evaluated in relation to wet heat (heat stress), menadione (oxidative stress), potassium chloride (osmotic stress), UV radiation, and 4-nitroquinoline-1-oxide (1/44-NQO genotoxic stress). Growth under hypoxic condition induced higher conidial tolerance of M. robertsii to menadione, KCl, and UV radiation. Transient anoxic condition induced higher conidial tolerance to KCl and UV radiation. Nutritional stress (i.e., minimal medium) induced higher conidial tolerance to heat, menadione, KCl, and UV radiation. However, neither of these treatments induced higher tolerance to 4-NQO. The gene hsp30 and hsp101 encoding a heat shock protein was upregulated under anoxic condition. In conclusion, growth under hypoxia and anoxia produced conidia with higher stress tolerances than conidia produced in normoxic condition. The nutritive stress generated by minimal medium, however, induced much higher stress tolerances. This condition also caused the highest level of gene expression in the hsp30 and hsp101 genes. Thus, the conidia produced under nutritive stress, hypoxia, and anoxia had greater adaptation to stress. & COPY; 2023 British Mycological Society. Published by Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 21/13614-3 - IV International Symposium on Fungal Stress - ISFUS & XIII International Fungal Biology Conference - IFBC
• Grantee: Drauzio Eduardo Naretto Rangel
• Support Opportunities: Organization Grants - Scientific Meeting
• FAPESP's process: 13/50518-6 - Stress related genes are induced by visible light during mycelial growth resulting in increased conidial tolerance to stress conditions
• Grantee: Drauzio Eduardo Naretto Rangel
• Support Opportunities: Regular Research Grants
• FAPESP's process: 10/06374-1 - Visible light during growth enhances conidial tolerance to different stress conditions in fungi
• Grantee: Drauzio Eduardo Naretto Rangel
• Support Opportunities: Research Grants - Young Investigators Grants