School of Plant Protection, Anhui Agricultural University, Hefei 230036, China; Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China; Anhui Province Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China; Hefei Research Center, State Key Laboratory for Biology of Plant Diseases and Insect Pests; Key Laboratory of Integrated Crop Pest Management of Anhui Province, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Pestic Biochem Physiol. 2023 Feb;190:105319. doi: 10.1016/j.pestbp.2022.105319. Epub 2022 Dec 16.
Southern corn leaf blight (SCLB), mainly caused by Bipolaris maydis, is a destructive disease of maize worldwide. Iprodione is a widely used dicarboximide fungicide (DCF); however, its antifungal activity against B. maydis has not been well studied until now. In this study, the sensitivity of 103 B. maydis isolates to iprodione was determined, followed by biochemistry and physiology assays to ascertain the fungicide's effect on the morphology and other biological properties of B. maydis. The results indicated that iprodione exhibited strong inhibitory activity against B. maydis, and the EC values in inhibiting mycelial growth ranged from 0.088 to 1.712 μg/mL, with a mean value of 0.685 ± 0.687 μg/mL. After treatment with iprodione, conidial production of B. maydis was decreased significantly, and the mycelia branches increased with obvious shrinkage, distortion and fracture. Moreover, the expression levels of the osmotic pressure-related regulation genes histidine kinase (hk) and Ssk2-type mitogen-activated protein kinase (ssk2) were upregulated, the glycerin content of mycelia increased significantly, the relative conductivity of mycelia increased, and the cell wall membrane integrity was destroyed. The in vivo assay showed that iprodione at 200 μg/mL provided 79.16% protective efficacy and 90.92% curative efficacy, suggesting that the curative effect was better than the protective effect. All these results proved that iprodione exhibited strong inhibitory activity against B. maydis and provided excellent efficacy in controlling SCLB, indicating that iprodione could be an alternative candidate for the control of SCLB in China.
南方玉米叶斑病（SCLB）主要由玉米弯孢菌引起，是一种对全球玉米具有破坏性的疾病。异菌脲是一种广泛使用的二羧酰亚胺类杀菌剂（DCF）；然而，直到现在，其对玉米弯孢菌的抗真菌活性还没有得到很好的研究。在本研究中，测定了 103 个玉米弯孢菌分离物对异菌脲的敏感性，然后进行了生物化学和生理学测定，以确定杀菌剂对玉米弯孢菌形态和其他生物学特性的影响。结果表明，异菌脲对玉米弯孢菌表现出很强的抑制活性，抑制菌丝生长的 EC 值范围为 0.088-1.712μg/mL，平均值为 0.685±0.687μg/mL。用异菌脲处理后，玉米弯孢菌的分生孢子产生明显减少，菌丝分枝增多，明显收缩、变形和断裂。此外，渗透压相关调节基因组氨酸激酶（hk）和 Ssk2 型丝裂原活化蛋白激酶（ssk2）的表达水平上调，菌丝甘油含量显著增加，菌丝相对电导率增加，细胞壁膜完整性被破坏。体内试验表明，200μg/mL 的异菌脲提供了 79.16%的保护效果和 90.92%的治疗效果，表明治疗效果优于保护效果。所有这些结果都证明异菌脲对玉米弯孢菌表现出很强的抑制活性，并对南方玉米叶斑病提供了优异的防治效果，表明异菌脲可能是中国防治南方玉米叶斑病的替代候选药剂。
