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Fungal diseases of plants are one of the key factors causing global crop losses. In this study, we isolated a Bacillus velezensis strain VC3, which was found to have a broad-spectrum inhibitory effect on a variety of phytopathogenic fungi through in vitro and in planta experiments, especially on Magnaporthe oryzae and Colletotrichum gloeosporioides. Further genomic and transcriptomic analyses revealed that the B. velezensis VC3 has multiple functional gene clusters encoding for the synthesis of a variety of antifungal secondary metabolites, including antimicrobial peptides (AMPs) and lipopeptides (LPs). In addition, AMPs and LPs were isolated and purified from B. velezensis VC3 fermentation broth and their antifungal activities were verified in this study. AMPs and LPs significantly inhibited spore germination, appressorium formation, and disease development, and AMPs have a better potential for controlling M. oryzae and C. gloeosporioides than LPs. These findings open new avenues for utilizing B. velezensis VC3 as biocontrol agents, providing potential sustainable solutions for agricultural production. [ABSTRACT FROM AUTHOR]

Pepper anthracnose caused by Colletotrichum gloeosporioides infection is an important fungal disease and represents a serious threat to pepper yield and quality. At present, the pathogenic molecular mechanism of C. gloeosporioides is not very clear. In our study, we characterized the function of C. gloeosporioides CgNis1, a homolog of Magnaporthe oryzae MoNis1. We found that the ∆Cgnis1 mutant reduced the growth rate and was defective in conidiation. Although the rate of appressorium formation was unaffected, the germ tube was found to be abnormal. CgNis1 was shown to be involved in the H2O2 stress response and maintaining cell membrane permeability. The pathogenicity assays performed in this study indicated that the deletion of CgNIS1 is associated with virulence. Our results indicate that CgNis1 is necessary for the growth, development, and pathogenicity of the fungus. This work provides an in-depth analysis of the Nis1 protein, helps to enhance studies on pathogen-related molecular mechanisms, and provides a theoretical basis for the prevention and control of C. gloeosporioides in peppers. [ABSTRACT FROM AUTHOR]

Secreted common fungal extracellular membrane (CFEM) domain proteins have been implicated in multiple biological functions in fungi. However, it is still largely unknown whether the ferric iron (Fe3+), as an important trace element, was involved with the biological function of CFEM proteins. In this study, a new CFEM protein CgCsa, with high expression levels at the early inoculation stage on peppers by Colletotrichum gloeosporioides was investigated. Deletion of the targeted gene CgCsa revealed multiple biological roles in hyphal growth restriction, highly reduced conidial yield, delayed conidial germination, abnormal appressorium with elongated bud tubes, and significantly reduced virulence of C. gloeosporioides. Moreover, in CgCsa mutants, the expression levels of four cell wall synthesis-related genes were downregulated, and cell membrane permeability and electrical conductivity were increased. Compared to the wild-type, the CgCsa mutants downregulated expressions of iron transport-related genes, in addition, its three-dimensional structure was capable binding with iron. Increase in the Fe3+ concentration in the culture medium partially recovered the functions of Δ CgCsa mutant. This is probably the first report to show the association between CgCsa and iron homeostasis in C. gloeosporioides. The results suggest an alternative pathway for controlling plant fungal diseases by deplete their trace elements. [ABSTRACT FROM AUTHOR]