Role of the yakA gene in morphogenesis and stress response in Penicillium marneffei

Abstract

Penicillium marneffei is a thermally dimorphic fungus and a highly significant pathogen of immunocompromised individuals living in or having travelled in south-east Asia. At 25 6C, P. marneffei grows filamentously. Under the appropriate conditions, these filaments (hyphae) produce conidiophores bearing chains of conidia. Yet, when incubated at 37 6C, or upon infecting host tissue, P. marneffei grows as a yeast that divides by binary fission. Previously, an Agrobacteriummediated transformation system was used to randomly mutagenize P. marneffei, resulting in the isolation of a mutant defective in normal patterns of morphogenesis and conidiogenesis. The interrupted gene was identified as yakA. In the current study, we demonstrate that the yakA mutant produced fewer conidia at 25 6C than the wild-type and a complemented strain. In addition, disruption of the yakA gene resulted in early conidial germination and perturbation of cell wall integrity. The yakA mutant exhibited abnormal chitin distribution while growing at 25 6C, but not at 37 6C. Interestingly, at both temperatures, the yakA mutant possessed increased chitin content, which was accompanied by amplified transcription of two chitin synthase genes, chsB and chsG. Moreover, the expression of yakA was induced during post-exponential-phase growth as well as by heat shock. Thus, yakA is required for normal patterns of development, cell wall integrity, chitin deposition, appropriate chs expression and heat stress response in P. marneffei.

Influence of environmental and nutritional conditions on yeast–mycelial dimorphic transition in Trichosporon cutaneum

“…Thus, as had been seen for other thermally dimorphic fungus, T. cutaneum B3 also showed morphological switch that was related to the temperature of cultivation. But the relationship between dimorphic transition and temperature of cultivation in T. cutaneum was the reverse of that described by Penicillium marneffei [53] and Blastomyces dermatitidis [54].…”

Trichoderma reesei Sch9 and Yak1 regulate vegetative growth, conidiation, and stress response and induced cellulase production

“…Moreover, it has been reported that Yak1 is involved in the initiation and maintenance of hyphal growth in Candida albicans (Goyard et al, 2008). Similar to S. cerevisiae Yak1, involvement of Yak1 orthologue in stress response in Penicillium marrneffei has been also reported (Suwunnakorn et al, 2014). Unlike Yak1, Sch9 is one of the AGC (protein kinase A, G, or C) kinases which is structurally related to the catalytic subunits of PKA.…”

Role of the MoYAK1 protein kinase gene in Magnaporthe oryzae development and pathogenicity

“…The C. albicans yak1‐ null mutant exhibits defects in yeast‐to‐hypha transition, maintaining hyphal growth and biofilm formation but remains virulent in animal models (Goyard et al ., ). The yakA mutant of Penicillium marneffei is defective in conidiation, conidial germination and cell wall integrity (Suwunnakorn et al ., ). The Fusarium graminearum knockout mutant for Yak1 is normal in vegetative growth, but exhibits defects in conidiation, disease development and stress response (Wang et al ., ).…”