Hydrophobin CmHYD1 Is Involved in Conidiation, Infection and Primordium Formation, and Regulated by GATA Transcription Factor CmAreA in Edible Fungus, Cordyceps militaris

Abstract

Hydrophobins are a family of small proteins exclusively secreted by fungi, and play a variety of roles in the life cycle. Cmhyd1, one of the hydrophobin class II members in Cordyceps militaris, has been shown to have a high transcript level during fruiting body development. Here, deletion of Cmhyd1 results in reduction in aerial mycelia, conidiation, hydrophobicity and infection ability, and complete inhibition of pigmentation and primordium differentiation. Cmhyd1 plays roles in conidiation and cuticle-bypassing infection by regulating the transcripts of frequency clock protein, Cmfrq, and velvet protein, Cmvosa, as well as primordium formation via the mitogen-activated protein kinase signaling pathway. Cmhyd1 also participates in stress response, including tolerance of mycelia to osmotic and oxidative stresses, and conidia to high or low temperatures. CmAreA, a transcription factor of nitrogen regulatory, is recruited to the promoter of Cmhyd1 and activates the transcription of Cmhyd1 with coactivator CmOTam using electrophoretic mobility shift assays and transient luciferase expression in tobacco. Furthermore, CmHYD1 is proved to regulate the transcription of Cmarea at different developmental stages via a positive feedback loop. These results reveal the diverse roles and regulation of Cmhyd1 in C. militaris, and provide insights into the developmental regulatory mechanism of mushrooms.

Efficient CRISPR/Cas9 system based on autonomously replicating plasmid with an AMA1 sequence and precisely targeted gene deletion in the edible fungus, Cordyceps militaris

“…Gene disruption, overexpression, and complementation have been performed using homologous recombination via ATMT in this fungus in our laboratory (Li et al, 2021 ; Xia et al, 2017 ; Yang et al, 2016 ; Zhang et al, 2020 ; Zheng et al, 2011 ). Initially, we attempted to perform CRISPR/Cas9 gene editing with pLC1‐sgRNA Cmwc−1 by ATMT; however, several failed attempts were documented (data not shown).…”

Isolation and Characterization of a Novel Hydrophobin, Sa-HFB1, with Antifungal Activity from an Alkaliphilic Fungus, Sodiomyces alkalinus

“…Hydrophobins (HFBs) are small proteins found only in filamentous fungi (Dikarya) [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. HFBs are characterized by their small size and amphipathic nature at hydrophilic/hydrophobic interfaces, and are currently attracting great interest from the biotechnology industry [ 38 , 39 , 40 , 41 ].…”

“…HFBs are characterized by their small size and amphipathic nature at hydrophilic/hydrophobic interfaces, and are currently attracting great interest from the biotechnology industry [ 38 , 39 , 40 , 41 ]. A central attraction is the ability of a hydrophobin monolayer to reverse the nature of a surface from hydrophobic to hydrophilic, and vice versa [ 31 , 37 , 42 ]. These layers cover fungal bodies and spores in water-repelling coats [ 37 ] and influence spore dispersal, stress resistance, development, and biotic interactions [ 43 , 44 , 45 ].…”

Cmcrf1, a Putative Zn2Cys6 Fungal Transcription Factor, Is Involved in Conidiation, Carotenoid Production, and Fruiting Body Development in Cordyceps militaris

“…In addition, all three genes affect carotenoid production. Genes participating in other metabolic pathways, such as Cmhyd1 encoding a class II hydrophobin and Cmfhp encoding an NO dioxygenase, have also been reported to regulate carotenoid accumulation and fungal development simultaneously [ 12 , 13 ]. The regulation of growth and development in response to environmental stimuli is a basic biological process in all organisms.…”

“…For example, recent studies have revealed that Cmhyd1 , which encodes a class II hydrophobin, may influence the yellow pigment accumulation in C. militaris . In particular, a Cmhyd1 -null mutant formed white colonies on potato dextrose agar (PDA) plates even after light irradiation [ 12 ]. Moreover, Cmfhp encodes flavohemoprotein, a nitric oxide (NO) dioxygenase, that was found to significantly affect carotenoid biosynthesis, as the carotenoid content of the Cmfhp -null mutant decreased compared with the WT strain in C. militaris [ 13 ].…”