Aug 2026· Virulence· Vol 17, pp.
2723679
· 0 citations· 58 references
Medicine
TL;DR
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.
Abstract
Sugarcane smut, caused by S. scitamineum, results in substantial economic losses across global sugarcane growing areas. Elucidating the pathogenic mechanisms of S. scitamineum is therefore crucial for developing effective disease control strategies. Our previous work has shown that the protein phosphatase SsPpe1 regulates mating and pathogenicity in S. scitamineum. In this study, we identified SsRts1 as a novel interacting protein of SsPpe1, which contains a PP2A regulator subunit B56 domain. Deletion of Ssrts1 gene impaired sporidia growth, resulting in pseudohyphal sporidia with multiple nuclei and aberrant chitin distribution. Further analysis revealed elevated phosphorylation levels of the cell cycle-related kinase CDK1T161 in the ΔSsrts1 mutants, suggesting that SsRts1 participates in mitosis regulation. Moreover, the ΔSsrts1 mutants exhibited increased sensitivity to cell wall, oxidative and high osmotic stresses. Mechanistically, SsRts1 negatively regulates the phosphorylation levels of the CWI-MAPK Mps1, implicating that SsRts1 is involved in regulating the cell wall integrity (CWI) pathway. Additionally, deletion of Ssrts1 also led to abnormal accumulation of autophagosome, along with defects in sexual mating, filamentation, and virulence. Global transcriptome profiling indicated that SsRts1 modulates ATPase activity, cell cycle progression, transmembrane transport, and tryptophan metabolism. Notably, exogenous supplementation with tryptophan partially restored the mating and filamentation defects in the ΔSsrts1 mutants, indicating that SsRts1 modulates these processes partly through the tryptophan catabolism pathway. Collectively, these findings provide insight into the regulatory roles of PP2A regulatory subunit SsRts1 in S. scitamineum, and expand our understanding of PP2A function in plant-pathogenic fungi.
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
Highlights This VdPRMT1 is a conserved arginine methyltransferase in Verticillium dahliae. VdPRMT1 contributes to fungal growth, stress adaptation, carbon utilization, and virulence. HIGS-mediated silencing of VdPRMT1 reduces Verticillium wilt severity in cotton. VdPRMT1 interacts with VdLuc7, indicating a potential link to RNA processing. Abstract Protein arginine methyltransferases (PRMTs) are key regulators of diverse cellular processes in eukaryotes, including transcriptional regulation, RNA processing, signal transduction and DNA repair. However, the biological functions of PRMTs in Verticillium dahliae remain largely unexplored. In this study, we identified a PRMT1 homolog in V. dahliae. Targeted deletion of VdPRMT1 resulted in severely impaired hyphal growth, sporulation, stress responses and pathogenicity. Subcellular localization analysis showed that VdPRMT1 is distributed in both the nucleus and cytoplasm of hyphae. Host-induced gene silencing (HIGS) of VdPRMT1 in cotton significantly reduced disease severity, supporting its important role in pathogenicity. Furthermore, VdLuc7, a U1 snRNP-associated protein containing multiple RG/RGG motifs, was identified as a putative interacting partner of VdPRMT1 through yeast two-hybrid (Y2H) screening, bimolecular fluorescence complementation (BiFC) and luciferase complementation imaging (LCI) assays. Together, our results demonstrate that VdPRMT1 is required for normal fungal development and full virulence in V. dahliae, and suggest that arginine methylation may contribute to pathogenicity through regulation of RNA processing-related pathways. These findings provide new insights into the molecular mechanisms underlying fungal virulence and identify VdPRMT1 as a potential target for disease control.
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.
Guiqiu Luo, Lirong Zhu, Hui Yuan et al.· Journal of Fungi· 0 citations
The SNF1‐related protein kinase 2 (SnRK2) pathway is a central regulator of abiotic stress signaling in land plants, yet its evolutionary origins and functional conservation across the green lineage remain poorly understood. To determine whether this signaling module predates the streptophyte–chlorophyte divergence, we investigated the chlorophyte alga Chlamydomonas reinhardtii, which diverged from the streptophyte lineage over 1 billion years ago. Using a combination of reverse genetics and protein–protein interaction assays, we identified and characterized a bona fide SnRK2 signaling module in C. reinhardtii. We demonstrate that the isoform SnRK2.7 is essential for osmotic stress tolerance and general cellular viability. SnRK2.7 localizes to the contractile vacuole, an osmoregulatory organelle lost during streptophyte evolution, revealing a lineage‐specific functional adaptation. Together with MAPKKK3, a B1/B3‐RAF kinase, and the clade A protein phosphatase PP2C3, these components constitute a MAPKKK3‐SnRK2.7‐PP2C3 regulatory module in C. reinhardtii. Our findings demonstrate the presence of a functional SnRK2 pathway in a chlorophyte alga, suggesting that core components were established early in the green lineage. This work provides a foundation for comparative studies across green plants and underscores the need for broader taxonomic sampling to reconstruct the ancestral signaling networks underlying stress adaptation.
Wenqing Yu, Kangning Guo, Yanyou Jiang et al.· New Phytologist· 0 citations
It is shown that the hyphae of the filamentous fungus Trichoderma guizhouense can differentiate into typical terminal and intercalary chlamydospores characterized by double-layered spherical or ellipsoidal cell walls with accumulated lipid bodies and nuclei, indicating the entry of cells into dormancy.
Yiting Hou, Yifan Li, Cheng Chen et al.· Applied and Environmental Mi...· 0 citations
It is shown that the understudied bZIP transcription factor PnAda1 is an important downstream component of this PnPf2-regulatory network, and current understanding of the transcriptional network underlying virulence, metabolism and stress adaptation in an important fungal wheat pathogen is expanded.
S. Morikawa, Leon Lenzo, Keshara Colomba Thanthrige et al.· bioRxiv· 0 citations