RESUMO
Fusarium head blight (FHB) and the presence of mycotoxin deoxynivalenol (DON) pose serious threats to wheat production and food safety worldwide. DON, as a virulence factor, is crucial for the spread of FHB pathogens on plants. However, germplasm resources that are naturally resistant to DON and DON-producing FHB pathogens are inadequate in plants. Here, detoxifying bacteria genes responsible for DON epimerization were used to enhance the resistance of wheat to mycotoxin DON and FHB pathogens. We characterized the complete pathway and molecular basis leading to the thorough detoxification of DON via epimerization through two sequential reactions in the detoxifying bacterium Devosia sp. D6-9. Epimerization efficiently eliminates the phytotoxicity of DON and neutralizes the effects of DON as a virulence factor. Notably, co-expressing of the genes encoding quinoprotein dehydrogenase (QDDH) for DON oxidation in the first reaction step, and aldo-keto reductase AKR13B2 for 3-keto-DON reduction in the second reaction step significantly reduced the accumulation of DON as virulence factor in wheat after the infection of pathogenic Fusarium, and accordingly conferred increased disease resistance to FHB by restricting the spread of pathogenic Fusarium in the transgenic plants. Stable and improved resistance was observed in greenhouse and field conditions over multiple generations. This successful approach presents a promising avenue for enhancing FHB resistance in crops and reducing mycotoxin contents in grains through detoxification of the virulence factor DON by exogenous resistance genes from microbes.
Assuntos
Resistência à Doença , Fusarium , Doenças das Plantas , Tricotecenos , Triticum , Triticum/microbiologia , Triticum/genética , Triticum/metabolismo , Fusarium/patogenicidade , Tricotecenos/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Resistência à Doença/genética , Genes Bacterianos/genéticaRESUMO
Soil erosion leads to soil degradation and depletion of land resources, posing a significant threat to industrial production and ecological sustainability. In high-altitude regions, rill erosion is the main form of soil erosion in mining areas, however, our understanding of morphology and developmental characteristics of rills and the mechanisms influencing them remains limited. In this study, data were collected from 96 rill plots across two gold mines in the eastern Tibetan Plateau according to vegetation restoration modes (natural restoration (CK) and planted with Elymus dahuricus (ED), Medicago sativa (MS), and multi-plant mixed (Avena fatua L. + Elymus dahuricus + Medicago sativa + Oxytropis coerulea, MM)) and restoration periods (1 year, 3 years, 4 years, and 6 years). We investigated the variations of 7 indicators that can reveal rill morphological and developmental characteristics across different restoration modes and restoration periods, and utilized a partial least squares structural equation model (PLS-SEM) to analyze the effects of 15 indicators from topography, soil, and vegetation on rill erosion modulus (REM). The results indicated that artificial vegetation restoration effectively restrained rill development, notably by decreasing the frequency of wider (>15 cm) and deeper (>10 cm) rills when compared to CK plots. Planting MM and ED exhibited greater efficacy in controlling rill erosion than planting MS. However, the effectiveness of planting ED in controlling rill erosion gradually weakened with time, while MM consistently maintained a strong inhibitory effect. Topographic features, soil texture, and vegetation significantly influenced the REM through direct or indirect effects. Plant root functional traits were the main driving factors in reducing REM, affecting not only REM directly but also influencing vegetation-induced soil properties to indirectly effect REM.