Development of Novel Bacteriostatic Agents Derived from Natural Product Formononetin and Their Action Mechanisms in Crop Diseases Management

The present study involved the development of a series of novel antibacterial compounds based on the structure of the natural product formononetin. The in vitro activity experiments demonstrated that compound M34 exhibited the most potent inhibitory effects against Xanthomonas oryzae pvoryzae (Xoo) and Xanthomonas axonopodis pv citri (Xac), with EC₅₀ values of 0.9 and 2.4 μg/mL, respectively. Pot experiments verified the excellent curative and protective effects of M34 against bacterial leaf blight of rice (BLB) and citrus canker (CC). Furthermore, a series of physiological and biochemical experiments were conducted to investigate the action mechanism exerted by M34 against plant pathogens Xoo and Xac. The findings revealed that M34 effectively inhibited the expression of multiple pathogenic factors, disrupted their energy metabolism, altered their cell membrane morphology, enhanced the activity of host defense enzymes, and attenuated their virulence toward host cells. Therefore, M34 could serve as a promising candidate drug for the inhibition of crop pathogens.