Potatoes are among the four most important staple crops worldwide. Verticillium wilt in potatoes caused by Verticillium dahliae is a devastating disease that is difficult to control. To identify potential avenues for disease control, the pathogenicity of 72 V. dahliae isolates was tested here. We also tested the resistance to the most virulent isolate (Vd-36) induced by the attenuated isolate Gibellulopsis nigrescens Vn-1 in potatoes. Induction of Verticillium wilt resistance in potatoes was strongest when using attenuated isolate Vn-1 to inoculate potatoes with a spore suspension concentration of 1 × 10⁶ conidia mL⁻¹, followed by infection with isolate Vd-36 at 5 d intervals. After incubation of potatoes with the attenuated isolate Vn-1 followed by isolate Vd-36, reactive oxygen species (ROS) and hydrogen peroxide (H₂O₂) were produced and accumulated in potato leaves 12 h post-inoculation. The changes in respective defense enzymes, except phenylalanine ammonia-lyase, were consistent with the changes in ROS and H₂O₂ levels. Furthermore, the content of salicylic acid (SA) in inoculated plants was higher than that in the control, and biosynthesis-related genes StNPR1, StPR1b, StPR2, StPR5 were activated. However, there was no significant difference in the jasmonic acid and ethylene (JA/ET) content between the treatment and control groups. These results demonstrated that the attenuated isolate Vn-1 enhanced resistance to Verticillium wilt by inducing the SA signalling pathway and weakly activating the JA/ET signalling pathways in potatoes.

(-)-Spirobrassinin, a glucosinolate compound from Brassicaceae plants, has shown inhibitory effects on weeds. However, its specific target sites are not well explored. This study used molecular docking, molecular dynamics simulations, and biological experiments to investigate (-)-Spirobrassinin’s target sites. The inhibitory effects of (-)-Spirobrassinin were observed on various enzymes crucial for plant metabolic pathways, including dihydroxyacid dehydrogenase, 4-hydroxyphenylpyruvate dioxygenase, protoporphyrinogen oxidase, and acetolactate synthase. Additionally, it disrupts the metabolism of vital phytohormones, namely abscisic acid and gibberellin. Molecular dynamics simulations revealed stable interactions between (-)-Spirobrassinin and specific residues (Phe270 and Phe261) of the photosystem II D1, involving electrostatic, hydrophobic, and van der Waals forces. This study provides valuable insights into (-)-Spirobrassinin’s mode of action, highlighting its potential as a natural herbicide from Brassicaceae plants.

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.

Brassica oleracea L. has strong allelopathic effects on weeds. However, the allelochemicals with herbicidal activity in B. oleracea L. are still unknown. In this study, we evaluated the activity of allelochemicals isolated from Brassica oleracea L. based on the germination and growth of model plant Lactuca sativa Linn., grass weed Panicum miliaceum, and broadleaf weed Chenopodium album. Additionally, we employed molecular docking to predict the binding of brassicanate A sulfoxide to herbicide targets. The results of this study showed that eight compounds with herbicidal activity were isolated from B. oleracea L., and the predicted results indicated that brassicanate A sulfoxide was stably bound to dihydroxyacid dehydratase, hydroxymethylpyruvate dioxygenase, acetolactate synthase, PYL family proteins and transport inhibitor response 1. This research provides compound sources and a theoretical foundation for the development of natural herbicides.

Brassicanate A sulfoxide, a secondary metabolite of broccoli, exhibited the inhibition of weed growth, but its mechanism of action on weeds remains unclear. To elucidate the mechanism by which brassicanate A sulfoxide suppresses weeds, this study explores the interaction between brassicanate A sulfoxide and the photosystem II D1 protein through molecular docking and molecular dynamics simulations. This research demonstrates that brassicanate A sulfoxide interacts with the photosystem II D1 protein by forming hydrogen bonds with Phe-261 and His-214. The successful expression of the photosystem II D1 protein in an insect cell/baculovirus system validated the molecular docking and dynamics simulations. Biolayer interferometry experiments elucidated that the affinity constant of brassicanate A sulfoxide with photosystem II was 2.69 × 10⁻³ M, suggesting that brassicanate A sulfoxide can stably bind to the photosystem II D1 protein. The findings of this study contribute to the understanding of the mode of action of brassicanate A sulfoxide and also aid in the development of natural-product-based photosynthesis-inhibiting herbicides.