An investigation into the possible regulation of the expression of genes by yapA in Talaromyces marneffei using the qRT- PCR method

Abstract

The pathogenic dimorphic fungus Talaromyces marneffei is known to cause a fatal systemic mycosis in immunocompromised patients, especially in HIV patients in Southeast Asia. The basic leucine-zipper (bZip) transcription factor gene, yapA, has been identified in T. marneffei. A prior study described that yapA was involved in the oxidative and nitrosative stress response in T. marneffei. Interestingly, an essential role of Saccharomyces cerevisiae Yap1p in the oxidative stress response is the activation of the transcription of its target genes. To identify the target genes of yapA in T. marneffei, the qRT-PCR method were used in this study. Investigation into the expression of genes which are probably regulated by yapA revealed that yapA controlled the expression of cat1 (catalase), cpeA (catalase-peroxidase), sodA (copper, zinc superoxide dismutase), gcs1 (glutamate-cysteine ligase), glr1 (glutathione oxidoreductase), trr1/trr2 (thioredoxin reductase), and trxA (thioredoxin) during stress conditions in all forms of conidium, mycelium, and yeast phase. An exception to this was the expression of cat1 under conditions of oxidative stress in the mould phase with a similar relative expression level in all of the wild-type, mutant and complemented strains. These genes are involved in response against oxidative stress and nitrosative stress in this fungus. The data showed that they could be regulated by the yapA gene during stress conditions. Moreover, the yapA gene is also known to control red pigment production by inhibiting the regulation of the five polyketide synthase (pks) genes, pks3 (polyketide synthase), rp1 (transcription activator), rp2 (β-subunit fatty acid synthase), rp3 (α-subunit fatty acid synthase), and rp4 (oxidoreductase) in the mould phase. In addition, it also regulates transcription in the laccase gene cluster including lac (extracellular dihydrogeodin oxidase/laccase), and multicopper oxidase encoding genes (PMAA_050860, PMAA_072680, PMAA_085520, PMAA_082010, and PMAA_082060) in all stages of the T. marneffei lifecycle (conidia, mould, and yeast phase). This study suggests the importance of the role of the yapA gene in the stress response and virulence of T. marneffei.

Disseminated Talaromyces marneffei infection initially presenting as cutaneous and subcutaneous lesion in an HIV-Negative renal transplant recipient: a case report and literature review

“…The incidence of invasive fungal infections such as T. marneffei infection has been increasing year by year due to long-term use of immunosuppressive drugs after kidney transplantation as well as the spread of pathogenic microorganisms caused by population movement and the genovariation of the pathogens themselves [ 46 – 48 ]. Thus, we absolutely cannot ignore the possibility of T. marneffei infection in non-HIV patients in nonendemic areas.…”

Identification of glutathione metabolic genes from a dimorphic fungus Talaromyces marneffei and their gene expression patterns under different environmental conditions

“…As an intracellular pathogen, T. marneffei has to alleviate the stress generated in the phagosomal environment. Previous studies reported the role of enzymatic antioxidants in T. marneffei , including superoxide dismutase and catalase-peroxidase; however, only a few studies have characterized the glutathione gene expression profiles 19 , 40 . Indeed, glutathione gene disruption studies have never been performed in this fungal species.…”

“…The expression of gst1 + and gst2 + is Pap1-dependent, whereas the induction of gst 3 + is Atf1-dependent 52 . In T. marneffei , the upregulation of TmGcs1 and TmGlr genes in response to oxidative stressors H 2 O 2 , menadione and NaNO 2 are dependent on yapA (Yap1 homolog) in all growth forms (conidia, mold, and yeast) 40 . Besides TmGcs1 and TmGlr genes, other glutathione metabolic genes were not tested in the study by Dankai et al Additionally, while the atfA (SpAtf1 homolog) deletion mutant in T. marneffei shows sensitivity to various oxidative stressors, whether glutathione metabolic gene expression is dependent on aftA was not tested 65 .…”

Post-genomic analysis of Monosporascus cannonballus and Macrophomina phaseolina - potential target selection

“…Table 2 provides information on these 13 candidate targets, including the sequence codes for target search and identification, their functions, alignment parameters (e-value and score), segment similarity, and references to research conducted on these target proteins outside the field of phytopathogenic fungi. The first target listed, Thioredoxin reductase Trr1/Trr2, plays distinct roles in the redox system involving cysteine synthesis and host infection (Dankai, Pongpom, & Vanittanakom, 2018). The second target, Mannose-1-phosphate guanylyltransferase, affects cell growth and morphology by altering cell membrane permeability (Taj et al, 2022).…”