Nanomaterials are increasingly being used for crop growth, especially as a new paradigm for plant disease management. Among the other nanomaterials, silver nanoparticles (AgNPs) draw a great deal of attention because of their unique features and multiple usages. Rapid expansion in nanotechnology and utilization of AgNPs in a large range of areas resulted in the substantial release of these nanoparticles into the soil and water environment, causing concern for the safety of ecosystems and phytosanitary. In an attempt to find an effective control measure for sweet potato soft rot disease, the pathogen Dickeya dadantii was exposed to AgNPs, the cell-free culture supernatant (CFCS) of Bacillus amyloliquefaciens alone, and both in combination. AgNPs were synthesized using CFCS of Bacillus amyloliquefaciens strain A3. The green synthesized AgNPs exhibited a characteristic surface plasmon resonance peak at 410–420 nm. Electron microscopy and X-ray diffraction spectroscopy determined the nanocrystalline nature and 20–100 nm diameters of AgNPs. Release of metal Ag⁺ ion from biosynthesized AgNPs increases with time. AgNPs and CFCS of B. amyloliquefaciens alone exhibited antibacterial activity against the growth, biofilm formation, swimming motility, and virulence of strain A3. The antibacterial activities elevated with the elevation in AgNPs and CFCS concentration. Similar antibacterial activities against D. dadantii were obtained with AgNPs at 50 µg·mL⁻¹, 50% CFCS alone, and the combination of AgNPs at 12 µg·mL⁻¹ and 12% CFCS of B. amyloliquefaciens. In planta experiments indicated that all the treatments reduced D. dadantii infection and increased plant growth. These findings suggest that AgNPs along with CFCS of B. amyloliquefaciens can be applied to minimize this bacterial disease by controlling pathogen-contaminated sweet potato tuber with minimum Ag nano-pollutant in the environment.

The DExD/H-box protein family encompasses a large number of RNA helicases that are involved in RNA metabolism and a variety of physiological functions in different species. However, there is limited knowledge of whether DExD/H-box proteins play a role in the pathogenicity of plant fungal pathogens. In the present work, the DExD/H-box protein MoDHX35, which belongs to the DEAH subfamily, was shown to be crucial in appressoria formation and full virulence of the rice blast fungus, Magnaporthe oryzae. The predicted protein sequence of MoDHX35 had typical DEAH-box domains, showed 47% identity to DHX35 in Homo species, but had no orthologs in Saccharomyces cerevisiae. Deletion of the MoDHX35 gene resulted in reduced tolerance of the mutants to doxorubicin, a nucleic acid synthesis disturbing agent, suggesting the involvement of MoDHX35 in RNA metabolism. MoDHX35-deleted mutants exhibited normal vegetative growth, conidia generation and conidial germination, but showed a reduced appressorium formation rate and attenuated virulence. Our work demonstrates the involvement of DEAH-box protein functions in the pathogenicity of plant fungal pathogens.

Magnaporthe oryzae, a fungal pathogen that causes rice blast, which is the most destructive disease of rice worldwide, has the potential to perform both asexual and sexual reproduction. MAT loci, consisting of MAT genes, were deemed to determine the mating types of M. oryzae strains. However, investigation was rarely performed on the development and molecular mechanisms of the sexual reproduction of the fungus. In the present work, we analyzed the roles of two MAT loci and five individual MAT genes in the sex determination, sexual development and pathogenicity of M. oryzae. Both of the MAT1-1 and MAT1-2 loci are required for sex determination and the development of sexual structures. MAT1-1-1, MAT1-1-3 and MAT1-2-1 genes are crucial for the formation of perithecium. MAT1-1-2 impacts the generation of asci and ascospores, while MAT1-2-2 is dispensable for sexual development. A GFP fusion experiment indicated that the protein of MAT1-1-3 is distributed in the nucleus. However, all of the MAT loci or MAT genes are dispensable for vegetative growth, asexual reproduction, pathogenicity and pathogenicity-related developments of the fungus, suggesting that sexual reproduction is regulated relatively independently in the development of the fungus. The data and methods of this work may be helpful to further understand the life cycle and the variation of the fungus.

Equol, a metabolite of soybean isoflavone daidzein, has been proven to have various bioactivities related to human health, but little is known on its antifungal activity to plant fungal pathogens. Magnaporthe oryzae is a phytopathogenic fungus that causes rice blast, a devastating disease on rice. Here, we demonstrated that equol influences the development and pathogenicity of M. oryzae. Equol showed a significant inhibition to the mycelial growth, conidial generation and germination, and appressorial formation of M. oryzae. As a result, equol greatly reduced the virulence of M. oryzae on rice and barley leaves. The antifungal activity of equol was also found in several other plant fungal pathogens. These findings expand our knowledge on the bioactivities of equol.

The sustainable utilization of rice straw is challenged by its recalcitrant lignocellulosic structure, especially under low-to-moderate field temperatures. In this study, a novel microbial consortium (SXJG15) mainly containing Sphingobacterium, Azospirillum, and Pseudomonas was enriched from overwintering rice stubble in Zhejiang, China, and evaluated for its rice straw degradation efficiency at 25 °C. Over an 18-day cultivation period, SXJG15 achieved a 52.5% degradation of total rice straw, including 60.2% cellulose, 76.3% hemicellulose, and 40.7% lignin. High extracellular enzymatic activities, including cellulases (up to 80.3 U/mL) and xylanases (up to 324.8 U/mL), were observed during the biodegradation process. 16S rRNA gene sequencing and metagenomics analyses revealed a succession of dominant taxa, including Sphingobacterium, Azospirillum, and Cellulomonas. Further, CAZy annotation indicated that the SXJG15 enzyme system was rich in glycoside hydrolases (42.7%) and glycosyltransferases (34.2%), demonstrating its high potential for lignocellulose degradation. This study uniquely demonstrates the mesophilic (moderate temperature 25 °C) efficiency of SXJG15 in lignocellulose breakdown, provides new insights into the microbial mechanisms of straw decomposition, and lays a foundation for bioenergy and soil fertility applications for developing a sustainable agriculture system.

Rice blast, caused by Magnaporthe oryzae, significantly threatens global rice production. Disease control is complicated by the pathogen’s high genetic diversity, which is driven by heterothallic recombination between opposite mating types that underlies variation. However, mechanisms governing sexual reproduction in this fungus remain poorly characterized, largely due to the absence of reliable methods for scalable ascospore progeny production. In this study, we established two novel mating methods, namely Conidial Mixing Mating (CMM) and Hyphal Segments Mixed Mating (HMM). Both methods employed optimized suspensions (5 × 10⁴ conidia/mL or equivalent hyphal density) mixed at 1:1 ratios, incubated under standardized conditions: 20 °C with a 12 h/12 h photoperiod. We characterized perithecia, asci, and ascospore morphology using fluorescence microscopy, paraffin sectioning, cryo-scanning electron microscopy, and transmission electron microscopy. Furthermore, both methods enabled phenotypic characterization of sexual reproduction-deficient mutants, including ΔMopmk1 and ΔMoopy2. In conclusion, we established two efficient methods for investigating M. oryzae sexual reproduction, providing foundational tools to advance studies of sexual mechanisms, pathogenicity evolution, and genetic variation.