A number of fungi have been shown to have negative effects on plant-parasitic nematodes. Most of these fungi have been isolated from soil, plant roots, or nematodes themselves. Fungi associated with crops can provide a diverse pool of candidates to test for antagonistic effects against plant parasites and other stressors. We used a hierarchical two-tiered approach to evaluate the efficacy and repeatability of 55 strains of fungi originally isolated as foliar facultative endophytes from upland cotton (Gossypium hirsutum) along with one commercial isolate of Beauveria bassiana for in planta antagonistic effects on root-knot nematodes (Meloidogyne incognita). All fungi were inoculated to cotton using a seed treatment. The number of root galls was quantified 3 weeks after egg inoculation of cotton seedlings. The majority of the fungi tested reduced the number of root galls relative to those on untreated control plants. To assess repeatability, 22 strains that exhibited the strongest reductions in gall numbers were further tested in replicate follow-up assays. Ninety-five percent (21/22) of these retested strains significantly reduced galling in the follow-up assay. Strains that reduced galling the most belonged to the genera Alternaria, Chaetomium, Cladosporium, Diaporthe, Epicoccum, Gibellulopsis, and Purpureocillium. On the contrary, three strains in the genera Alternaria and Curvularia significantly increased gall numbers. Our results indicate that a large proportion of the fungal strains originally isolated from cotton as naturally occurring foliar facultative endophytes are capable of reducing root-knot nematode infection when applied back to the plant as a seed treatment. These findings help establish a rich pool of candidate fungi for further evaluation as novel biological control tools against root-knot nematodes in cotton and other plants.

Gravel-sand mulching is a traditional agricultural practice in arid and semiarid regions, providing a surface barrier for soil and water conservation. However, application of such practice in monocropping systems may lead to outbreaks of several devastating plant diseases, such as watermelon Fusarium wilt.

Expansion of photovoltaic infrastructure in arid regions raises concerns about soil microhabitat degradation. Very few studies have systematically compared these recovery alternatives in reshaping the soil fungal communities during early recovery. This study investigated short-term effects (less that two-year recovery) of PV infrastructure and restoration (natural/artificial) on soil fungal diversity and enzymatic activities in Ningxia desert steppe. A total of 243 soil samples were analyzed to assess fungal diversity, composition, enzyme activities, and co-occurrence networks. The restoration method significantly affected soil fungal α-diversity and β-diversity in the experimental solar park. Specifically, at each recovery site, soil depth showed significant effect on fungal α-diversity. However, on a fine scale, artificial restoration significantly increased fungal species richness across soil depths. Ascomycota dominated across different sites, followed by Basidiomycota and Mucoromycota. Shared core genera Fusarium, Mortierella, and Geminibasidium were determined in both recovery sites. Sucrase/phenol oxidase (natural) and catalase/sucrase (artificial) were identified as key fungal drivers according to Random Forest models. Co-occurrence analysis suggested neither artificial restoration nor natural restoration has attained the level of natural habitats. Networks of artificial subsoil and natural topsoil were closest to natural habitat. These results emphasize the impact of restoration and PV shading on fungal communities via spatial heterogeneity and enzyme dynamics during initial recovery stage, providing insights for semi-arid ecosystem management under PV development.