A DnaJ-like Homolog from Cryphonectria parasitica Is Not Responsive to Hypoviral Infection but Is Important for Fungal Growth in Both Wild-Type and Hypovirulent Strains

Abstract

A DnaJ-like gene, Cpdj1, a molecular chaperone and regulator of Hsp70 in Cryphonectria parasitica, was characterized. The protein product of Cpdj1 gene consists of 379 amino acids with a predicted molecular mass of 40.6 kDa and a pI of 7.79. The deduced protein sequence revealed preservation of the conserved hall-mark J-region and exhibited high homolo y to all known DnaJ-like proteins. Disruption of the Cpdj1 gene resulted in slow growth and produced colonies characterized by retarded growth and deep orange color. Accordingly, reduced virulence of the Cpdj1-null mutant was observed. This reduced growth rate was magnified when the Cpdj1-null mutant was cultured under heat-stress conditions. Reduced conidiation was also observed in the Cpdj1-null mutant, indicating that Cpdj1 gene, although not essential for cell viability, is required for appropriate cellular processes including growth and sporulation. Northern analysis showed that Cpdj1 was constitutively expressed, and when the culture was subject to high temperature, a strong induction of the transcript was observed. No significant difference in the expression and induction pattern of Cpdj1 was observed between virus-free EP155/2 and virus-infected hypovirulent UEP1 strains. However, further severe defects in mycelia growth and conidiation were observed in the hypovirus-infected Cpdj1-null mutant suggesting that the presence of Cpdj1 is required for mycelia growth and sporulation of the hypovirus-infected strain.

Dnj1 Promotes Virulence in Cryptococcus neoformans by Maintaining Robust Endoplasmic Reticulum Homeostasis Under Temperature Stress

“…Previously, heat shock proteins such as Hsp70 and Hsp90 were shown to be required for the virulence of fungal pathogens and have been proposed as potential antifungal therapeutic targets (Cowen et al, 2009;Brown et al, 2010;Sun et al, 2010;Nagao et al, 2012;Cowen, 2013;Cordeiro et al, 2016;Tiwari and Shankar, 2018;Weissman et al, 2020). Along with these major classes of chaperones, the co-chaperones also play important roles in virulence and the elaboration of virulence-related traits such as dimorphic switching, effector secretion, and polysaccharide capsule formation (Lim et al, 2010;Lo Presti et al, 2016;Xie et al, 2017;Horianopoulos et al, 2020;Jurick et al, 2020;Son et al, 2020).…”

Hypoviral‐regulated HSP90 co‐chaperone p23 (CpCop23) determines the colony morphology, virulence, and viral response of chestnut blight fungusCryphonectria parasitica

“…Systemic analysis of transcripts and proteins of both virus‐free and virus‐infected isogenic strains of C. parasitica has revealed that these phenotypic changes are attributable to hypoviral modulations in the fungal gene expression profiles (Allen & Nuss, 2004 ; Allen et al, 2003 ; Chun et al, 2020 ; Deng et al, 2007 ; Kang et al, 1999 ; Kazmierczak et al, 1996 , 2012 ; Kim et al, 2012 ; Wang et al, 2013 ). Among the several fungal pathways regulated by the hypovirus infection, the stress‐response pathway, which includes specific heat‐shock proteins, has been shown to be one of the specific targets perturbed by the hypovirus infection (Allen & Nuss, 2004 ; Allen et al, 2003 ; Baek et al, 2014 ; Lim et al, 2010 ). Our previous studies using a growth condition supplemented with tannic acid (TA), which is abundant in the bark of chestnut trees and is assumed to be the major defence material against pathogen infection, demonstrated that a gene encoding a co‐chaperone of heat‐shock protein 90 is specifically regulated by the presence of hypovirus CHV1 and TA supplementation (Kim et al, 2012 ).…”