Aug 2026· Journal of Fungi· Vol 12, pp. 595· 0 citations· 47 references
Medicine
TL;DR
It is demonstrated that AoPtp is a pleiotropic regulator of sporulation, trap development, stress tolerance, and metabolic process in A. oligospora, and its potential applications in biocontrol of nematode-associated diseases are explored.
Abstract
Arthrobotrys oligospora is a widely distributed nematode-trapping (NT) fungus that captures nematodes by developing flexible traps. In fungi, protein tyrosine phosphatases (PTPs) are crucial for intracellular signaling, governing processes such as cell growth, proliferation, and differentiation in filamentous species. In this study, we characterized the functions of AoPtp (an orthologous PTP) through gene knockout, phenotypic, multi-omics, and yeast two-hybrid (Y2H) analyses. Inactivation of Aoptp caused a marked increase in trap number and nematode predation ability. The ΔAoptp mutants exhibited enhanced mycelial growth on TYGA and TG media, but showed no significant growth difference on PDA medium, together with reduced spore yield, and altered stress responses. In addition, phenotypic and transcriptomic analyses suggested that AoPtp is associated with lipid droplet accumulation and autophagy-related processes. Metabolomic analysis revealed extensive changes in metabolic profiles, including an approximately six-fold reduction in arthrobotrisin abundance. Furthermore, AoPtp interacts with AoFus3 and AoSlt2 in a Y2H assay, suggesting its potential involvement in the mitogen-activated protein kinase signaling pathway. In summary, we demonstrated that AoPtp is a pleiotropic regulator of sporulation, trap development, stress tolerance, and metabolic process in A. oligospora. These findings provide a basis for probing the regulatory mechanism of PTPs underlying trap formation in NT fungi, as well as for exploring their potential applications in biocontrol of nematode-associated diseases.
Sporulation is essential for asexual reproduction and dispersal in filamentous fungi, but the roles of upstream sporulation regulators in nematode-trapping (NT) fungi remain poorly understood. In this study, we characterized two Flb homologs, AoFlbB and AoFlbD, in Arthrobotrys oligospora. AoFlbB contains a bZIP-type domain, whereas AoFlbD contains a Myb-like DNA-binding domain, and both proteins are conserved among NT fungi. Deleting AoflbB or AoflbD had little effect on hyphal growth but markedly reduced spore production and altered spore germination, and real-time quantitative PCR analysis showed that the central sporulation regulators were significantly differently expressed, collectively indicating that AoFlbB and AoFlbD play positive roles in sporulation. Furthermore, both mutants produced more traps and showed enhanced nematode predation efficiency. The mutants also showed altered cell wall stress responses, hyphal cell length, nuclear number, endocytic trafficking, and metabolite profiles. The ΔAoflbB mutant showed irregular cell wall wrinkling, whereas the ΔAoflbD mutant displayed increased vesicle-like structures and accelerated FM4-64 uptake. Extracellular protease activity was comparable to the WT in ΔAoflbB but reduced in ΔAoflbD. Transcriptomic analysis of ΔAoflbD showed that the differentially expressed genes were significantly enriched in metabolism-related pathways. These findings indicate that AoFlbB and AoFlbD promote sporulation and contribute to the coordination of asexual reproduction and trap formation in A. oligospora.
Yi Chen, Yanmei Shen, Hui Yuan et al.· Microorganisms· 0 citations
Insight is provided into the regulatory roles of PP2A regulatory subunit SsRts1 in S. scitamineum, and the understanding of PP2A function in plant-pathogenic fungi is expanded.
Jinfeng Qiu, Hao-Ming Wu, Ying Liu et al.· Virulence· 0 citations
It is demonstrated that AaAtg4 is important for spore germination, siderophore biosynthesis, iron acquisition, oxidative stress resistance, and toxin production, thereby establishing its critical role in A. alternata virulence.
Hsin-Yu Lu, C. H. Y. Choo, Je-Jia Wu et al.· Fungal Genetics and Biology· 0 citations
SH3 domain-containing proteins mediate protein–protein interactions, facilitate membrane localization, and regulate intracellular signaling pathways in eukaryotes. Although cellulolytic fungi harbor multiple SH3-containing proteins, their roles in cellulase secretion and stress adaptation have never been studied. This study identified 25 SH3-domain-containing proteins in the model cellulolytic filamentous fungus Talaromyces pinophilus. Transcriptomic analysis further revealed a FUS1p homolog SH3 protein, TpSH3A, which was uniquely downregulated in the presence of cellulose. Functional characterization of TpSH3A using knockout and complementation analyses demonstrated that deletion of Tpsh3a adversely affects fungal growth, while concomitantly enhancing the secretion of cellulose-degrading enzymes. Interestingly, the ΔTpsh3a strain exhibited pronounced sensitivity to oxidative and endoplasmic reticulum stress, as evidenced by impaired growth under allyl alcohol and hydrogen peroxide, an attenuated unfolded protein response, and dysregulated reactive oxygen species homeostasis. Quantitative differential proteomic analysis showed coordinated downregulation of proteins involved in respiration, ATP generation, and the unfolded protein response, along with upregulation of β-glucosidases, indicating a role in cellular energy metabolism and secretory output. In concordance, pull-down analyses suggested that TpSH3A interacts with proteins involved in oxidative phosphorylation, intracellular transport, and membrane organization. These findings highlight TpSH3A as an important factor linking environmental sensing with enzyme secretion, optimizing T. pinophilus’s capacity for biomass degradation.
Unknown authors· Journal of Proteome Research· 0 citations
Sugarcane smut, caused by Sporisorium scitamineum, is one of the most devastating diseases of sugarcane worldwide, leading to severe yield losses and long-term agricultural impacts. Integral membrane proteins are essential components of plasma membranes, playing critical roles in molecular transport, signal transduction, pathogenesis, and defense. However, their contributions to sexual mating and pathogenicity in smut fungi remain largely unknown. In this study, we sought to characterize two novel integral membrane proteins—regulation of whip and teliospore development 1 (RWTD1) and pheromone-regulated multispanning membrane protein (PRM1)—in S. scitamineum. The RWTD1 protein, which contains four transmembrane domains, showed mating-specific upregulation and localized to discrete puncta in the cytoplasm near the cell membrane. The deletion of RWTD1 in Mat-1 haploids abolished filamentous growth after sexual mating, whereas its deletion in Mat-2 haploids resulted in reduced filamentation. Transcriptome profiling revealed that, relative to the wild type, genes encoding several integral and intrinsic membrane components were differentially expressed in RWTD1 mutants, including PRM1 and DIK6, which encode putative four- and seven-transmembrane domain proteins, respectively. Deleting PRM1 recapitulated the mating defects observed in the ΔRWTD1 mutants. While RWTD1, PRM1, and DIK6 contributed to virulence, RWTD1 also functioned in symptom development and teliospore formation. Overall, our work demonstrated that the transmembrane proteins RWTD1, PRM1, and DIK6 are important contributors to virulence and sexual mating in the sugarcane smut fungus.
Shan Lu, Shaofeng Tan, Mi Liang et al.· Phytopathology Research· 0 citations
Fungi have evolved sophisticated mechanisms to survive in complex environments. Nematode-trapping fungi (NTF) sense and recognize nematode prey to transition from a saprophytic to predatory lifestyle, rendering them promising biocontrol agents against plant-parasitic nematodes. Ubiquitination is essential for eukaryotic cellular homeostasis, yet its regulation of NTF development and pathogenicity remains unclear. Here, we identify the conserved E3 ubiquitin ligase AoRsp5 as a critical factor for all major life stages of Arthrobotrys oligospora. Knockout of rsp5 impairs Endosomal Sorting Complex Required for Transport (ESCRT)-mediated endocytosis and compromises plasma membrane integrity. These defects trigger disturbed cellular iron homeostasis and ferroptosis-like cell death, accompanied by global dysregulation of protein phosphorylation and ubiquitination as well as prominent suppression of MAPK cascades, which further attenuate virulence-associated signaling. Overall, our findings reveal a pivotal role for Rsp5-mediated ubiquitination in coordinating cellular homeostasis and developmental transitions in NTF.
Xiqi Zhang, Hai-Long Pu, Run-Liu He et al.· Journal of Fungi· 0 citations
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