Arginine Methyltransferase PeRmtC Regulates Development and Pathogenicity of Penicillium expansum via Mediating Key Genes in Conidiation and Secondary Metabolism

Abstract

Penicillium expansum is one of the most common and destructive post-harvest fungal pathogens that can cause blue mold rot and produce mycotoxins in fruit, leading to significant post-harvest loss and food safety concerns. Arginine methylation by protein arginine methyltransferases (PRMTs) modulates various cellular processes in many eukaryotes. However, the functions of PRMTs are largely unknown in post-harvest fungal pathogens. To explore their roles in P. expansum, we identified four PRMTs (PeRmtA, PeRmtB, PeRmtC, and PeRmt2). The single deletion of PeRmtA, PeRmtB, or PeRmt2 had minor or no impact on the P. expansum phenotype while deletion of PeRmtC resulted in decreased conidiation, delayed conidial germination, impaired pathogenicity and pigment biosynthesis, and altered tolerance to environmental stresses. Further research showed that PeRmtC could regulate two core regulatory genes, PeBrlA and PeAbaA, in conidiation, a series of backbone genes in secondary metabolism, and affect the symmetric ω-NG, N’G-dimethylarginine (sDMA) modification of proteins with molecular weights of primarily 16–17 kDa. Collectively, this work functionally characterized four PRMTs in P. expansum and showed the important roles of PeRmtC in the development, pathogenicity, and secondary metabolism of P. expansum.

Histone H3K4 Methyltransferase PeSet1 Regulates Colonization, Patulin Biosynthesis, and Stress Responses of Penicillium expansum

“…Phenotype analysis was performed as previously described ( 63 , 65 , 66 ), and all the experiments were repeated three times.…”

“…Total RNA was isolated from mycelia using TRNzol Universal Reagent (Tiangen; DP424) according to the instructions. Reverse transcription and quantitative PCR (qPCR) were carried out as described previously ( 63 , 66 ). The quantitation of gene expression was normalized by β - tubulin gene and relative expression levels were calculated with the 2 −ΔΔCt method ( 67 ).…”

“…Histones were resuspended in lysis buffer (7 M urea, 2 M thiourea, 2% carrier ampholytes, 4% CHAPS, and 1% DTT) and quantified by the Bradford method. The procedure of Western bolt was performed as previously described with a few modifications ( 66 ). An equal amount of histone (10 μg) was separated by 15% SDS-PAGE.…”

Erg4 Is Involved in Ergosterol Biosynthesis, Conidiation and Stress Response in Penicillium expansum

“…Spores were obtained by adding 10 mL of sterile water to each plate. Sporulation was counted using a hemocytometer r [ 18 ].…”

Comparative Penicillium spp. Transcriptomics: Conserved Pathways and Processes Revealed in Ungerminated Conidia and during Postharvest Apple Fruit Decay

“…Among the genes that have been well characterized in P. expansum are those that encode transcription factors that modulate a variety of essential biological, developmental, and virulence functions, including LaeA, SntB, CreA, VeA, Ste12, PacC, and PeMetR [21][22][23][24][25][26][27][28]. Other relevant genes encode regulatory factors involved with reactive oxygen species (NoxR, NoxA, RacC), gluconic acid accumulation (GOX2), or vesicle-based secretion (Blistering1) [19,29,30], as well as genes encoding enzymes involved in the synthesis and regulation of secondary metabolites (PeRmtC, patulin gene cluster) [27,31,32]. Both reverse and forward genetic approaches have been implemented to determine the role of these genes in fungal virulence and apple fruit decay.…”