Soe Zar Zar, Shin Yong Ho, Jeun Yong Chull
Sustainable Agriculture Research Institute, Jeju National University, Jeju 63243, Korea.
The Research Institute for Subtropical Agriculture and Biotechnology, Jeju National University, Jeju 63604, Korea.
Plant Pathol J. 2024 Dec;40(6):603-614. doi: 10.5423/PPJ.OA.07.2024.0112. Epub 2024 Dec 1.
Infection behaviors of some susceptible and resistant Diaporthe citri isolates against two fungicides such as benomyl and kresoxim-methyl were observed on citrus leaves. On the chemically unsprayed leaves, there were no differences in not only the conidial germination rate but also hyphal growth between the resistant and susceptible isolates. However, on the benomyl or kresoximmethyl-pretreated leaves, both conidial germination rate and hyphal growth of the resistant isolates were not decreased, which was different with those of the susceptible isolates. These unchanging germination rate and hyphal growth of the resistant isolates, resulting in the lack of chemical efficacy, coincided with the previous studies in which strong infection was observed by the resistant isolates after pre-treatment with each chemical. On the other hand, a point mutation occurred at 198th amino acid of β-tubulin gene in the resistant isolate NEL21-2 which may cause the resistant against benomyl. However, no mutation was found in cytochrome b in the resistant isolates indicating other genomic changes may be responsible for the resistant against kresoxim-methyl.
在柑橘叶片上观察了一些柑桔间座壳菌敏感和抗性分离株对两种杀菌剂（如苯菌灵和嘧菌酯）的侵染行为。在未进行化学喷雾处理的叶片上，抗性和敏感分离株在分生孢子萌发率和菌丝生长方面均无差异。然而，在经苯菌灵或嘧菌酯预处理的叶片上，抗性分离株的分生孢子萌发率和菌丝生长均未降低，这与敏感分离株不同。抗性分离株这些不变的萌发率和菌丝生长导致化学防治效果不佳，这与之前的研究结果一致，即在每种化学药剂预处理后，抗性分离株表现出较强的侵染能力。另一方面，抗性分离株NEL21-2的β-微管蛋白基因第198位氨基酸发生了点突变，这可能导致对苯菌灵产生抗性。然而，在抗性分离株的细胞色素b中未发现突变，表明其他基因组变化可能是对嘧菌酯产生抗性的原因。
