Three proline rotamases involved in calcium homeostasis play differential roles in stress tolerance, virulence and calcineurin regulation of Beauveria bassiana

• Published in: Cellular microbiology Vol. 22; no. 10; pp. e13239 - n/a
• Main Authors: Mouhoumed, Amina‐Zahra, Mou, Ya‐Ni, Tong, Sen‐Miao, Ying, Sheng‐Hua, Feng, Ming‐Guang
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Inc 01.10.2020; Hindawi Limited
• Subjects: Beauveria bassiana; Calcineurin; calcineurin activity; Calcium; Calcium homeostasis; Calcium ions; Calcium signalling; Cell walls; cellular Ca2+ homeostasis; conidiation; Copper; Deoxyribonucleic acid; Detoxification; DNA; DNA damage; DNA repair; Drug resistance; entomopathogenic fungi; FK506‐sensitive proline rotamases; Fungi; gene expression and regulation; growth; Heat shock; Homeostasis; Hydrogen peroxide; Immunosuppressive agents; immunosuppressive drug resistance; Insects; Iron; Irradiation; Magnesium; Mutants; Proline; Signal transduction; stress response; Tacrolimus; Ultraviolet radiation; Virulence; Yeasts; Zinc; calcineurin activity; entomopathogenic fungi; stress response; virulence; immunosuppressive drug resistance; FK506-sensitive proline rotamases; growth; conidiation; gene expression and regulation; cellular Ca2+ homeostasis
• ISSN: 1462-5814; 1462-5822
• DOI: 10.1111/cmi.13239

FK506‐sensitive proline rotamases (FPRs), also known as FK506‐binding proteins (FKBPs), can mediate immunosuppressive drug resistance in budding yeast but their physiological roles in filamentous fungi remain opaque. Here, we report that three FPRs (cytosolic/nuclear 12.15‐kD Fpr1, membrane‐associated 14.78‐kD Fpr2 and nuclear 50.43‐kD Fpr3) are all equally essential for cellular Ca2+ homeostasis and contribute significantly to calcineurin activity at different levels in the insect‐pathogenic fungus Beauveria bassiana although the deletion of fpr1 alone conferred resistance to FK506. Radial growth, conidiation, conidial viability and virulence were less compromised in the absence of fpr1 or fpr2 than in the absence of fpr3, which abolished almost all growth on scant media and reduced growth moderately on rich media. The Δfpr3 mutant was more sensitive to Na+, K+, Mn2+, Ca2+, Cu2+, metal chelate, heat shock and UVB irradiation than was Δfpr2 while both mutants were equally sensitive to Zn2+, Mg2+, Fe2+, H2O2 and cell wall‐perturbing agents. In contrast, the Δfpr1 mutant was less sensitive to fewer stress cues. Most of 32 examined genes involved in DNA damage repair, Na+/K+ detoxification or osmotolerance and Ca2+ homeostasis were downregulated sharply in Δfpr2 and Δfpr3 but rarely so affected in Δfpr1, coinciding well with their phenotypic changes. These findings uncover important, but differential, roles of three FPRs in the fungal adaptation to insect host and environment and provide novel insight into their essential roles in calcium signalling pathway.