Affiliation:
1. College of Forestry Jiangxi Agricultural University, East China Woody Fragrance and Flavor Engineering Research Center of National Forestry and Grassland Administration, Jiangxi Provincial Key Laboratory of Improved Variety Breeding and Efficient Utilization of Native Tree Species Nanchang China
2. College of Agronomy Jiangxi Agricultural University, Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Jiangxi Super Rice Engineering Technology Research Center Nanchang China
3. College of Life Sciences Nanchang Normal University Nanchang China
Abstract
AbstractBACKGROUNDRice sheath blight caused by Rhizoctonia solani is a severe threat to the yield and quality of rice. Due to the unscientific abuse of common fungicides causing resistance and environmental issues, the development of new fungicides is necessary. In this study, we used citral as the lead compound, designed and synthesized a series of novel citral amide derivatives, and evaluated their antifungal activity and mode of action against R. solani.RESULTBioassay results indicated that the antifungal activities of most citral amide derivatives against R. solani were significantly improved compared to citral, with EC50 values ranging from 9.50–27.12 mg L−1. Among them, compound d21 containing the N‐(pyridin‐4‐yl)carboxamide group exhibited in vitro and in vivo fungicidal activities, with curative effects at 500 mg L−1 as effectively as the commercial fungicide validamycin·bacillus. Furthermore, d21 prolonged the lag phase of the growth curve of R. solani, reduced the amount of growth, and inhibited sclerotium germination and formation. Mechanistically, d21 deformed the mycelia, increased cell membrane permeability, and inhibited the activities of antioxidant and tricarboxylic acid cycle (TCA)‐related enzymes. Metabolome analysis showed the abundance of some energy‐related metabolites within R. solani increased, and simultaneously the antifungal substances secreted by itself reduced. Transcriptome analysis showed that most genes encoding ATP‐binding cassette (ABC) transporters and peroxisomes upregulated after the treatment of d21 and cell membrane destruction.CONCLUSIONThis study indicates that novel citral amide derivatives possess antifungal activity against R. solani and are expected to develop an alternative option for chemical control of rice sheath blight. © 2024 Society of Chemical Industry.