Allelopathic interactions between plants serve as powerful tools for weed control. Despite the increasing understanding of the allelopathic mechanisms between different plant species, the inhibitory effects of B. oleracea on weed growth remain poorly understood. In this study, we conducted experiments to demonstrate that B. oleracea extract can suppress the germination of Panicum miliaceum L.varruderale Kit. seeds as well as of the roots, shoots and hypocotyl elongation of P. miliaceum seedlings. Furthermore, we observed that B. oleracea extract reduced the levels of hydrogen peroxide and superoxide anion in the roots while increasing the activities of catalase and ascorbate peroxidase. In the shoots, B. oleracea extract enhanced the activities of superoxide dismutase and peroxidase. Moreover, the use of the extract led to an increase in the content of phytohormones (indole-3-acetic acid, indole-3-acetaldehyde, methyl indole-3-acetate, N6-isoPentenyladenosine, dihydrozeatin-7-glucoside, abscisic acid and abscisic acid glucose ester) in P. miliaceum seedlings. Interestingly, the aqueous extract contained auxins and their analogs, which inhibited the germination and growth of P. miliaceum. This may contribute to the mechanism of the B. oleracea-extract-induced suppression of P. miliaceum growth.

Potato Fusarium Wilt is a soil-borne fungal disease that can seriously harm potatoes throughout their growth period and occurs at different degrees in major potato-producing areas in China. To reduce the use of chemical agents and improve the effect of biocontrol agents, the inhibitory effects of the fermentation broth of Bacillus subtilis ZWZ-19 (B) and Trichoderma asperellum PT-29 (T) on Fusarium oxysporum were compared under single-culture and co-culture conditions. Furthermore, metabolomic analysis of the fermentation broths was conducted. The results showed that the inhibitory effect of the co-culture fermentation broth with an inoculation ratio of 1:1 (B1T1) was better than that of the separately cultured fermentation broths and had the best control effect in a potted experiment. Using LC-MS analysis, 134 metabolites were determined and classified into different types of amino acids. Furthermore, 10 metabolic pathways had the most significant variations, and 12 were related to amino acid metabolism in the KEGG analysis. A correlation analysis of the 79 differential metabolites generated through the comprehensive comparison between B, T, and B1T1 was conducted, and the results showed that highly abundant amino acids in B1T1 were correlated with amino acids in B, but not in T.

Biofumigation is increasingly recognized as an effective strategy for managing soilborne diseases. However, the understanding of the mechanisms of biofumigation has mostly focused on its direct inhibitory effects on plant pathogens, while the rhizosphere microbe-mediated effects induced by biofumigation remain unclear. Here, we investigated the effects of broccoli (Brassica oleracea var. italica) biofumigation on potato Fusarium wilt caused by Fusarium oxysporum and elucidated the changes in rhizosphere bacterial assemblage under biofumigation. Results showed that biofumigation significantly reduced disease incidence and increased tuber yield. In vitro assays revealed a strong direct inhibition of F. oxysporum by broccoli biofumigation, but the inhibition rate decreased from 99.78% on the first day to 76.27% on the seventh day. High-throughput sequencing and culture-based analyses demonstrated that biofumigation significantly shifted bacterial community assemblage in potato rhizosphere, enriching antagonistic taxa against F. oxysporum. Functional prediction suggested that biofumigation enriched bacteria associated with nitrogen consumption and methylotrophy. The changes in the rhizosphere bacterial community showed significant correlations with the incidence and severity of Fusarium wilt, indicating that biofumigation indirectly enhanced crop resistance to plant pathogens by altering the rhizosphere microbial community. These findings extend the current understanding of biofumigation beyond direct chemical toxicity and classical antibiosis and highlight its potential as an ecological strategy that harnesses the plant-associated microbiome for disease management.

Potato Fusarium wilt, caused primarily by Fusarium oxysporum, is a significant soil-borne disease posing a serious threat to global potato production, with

Cenchrus pauciflorus Benth. (field sandbur) is a highly invasive weed with strong drought tolerance. However, the contribution of seed-associated endophyte