中华猕猴桃褐斑病病原鉴定及抑菌药剂筛选

【目的】确定引起中华猕猴桃褐斑病病原菌种类，研究常用杀菌剂对该病原菌菌丝生长的抑制作用。【方法】对病原菌进行分离、纯化、致病性测定以及形态学、分子生物学鉴定，确定病原菌种类；选用常用的18种杀菌剂分别对病原菌进行抑菌效果测定，并建立毒力回归方程；筛选出有效的抑菌药剂，为防治该病的发生提供理论依据。【结果】从不同病斑上分离出了3个纯化菌株，其形态特征相同。通过病原菌rDNA-ITS克隆测序、比对分析，3个菌株为同一致病菌，应用BLASTn比对结合形态学特征确定该致病菌为链格孢（Alternaria alternata (Fr.:Fr.) Keissler）。在10 μg•mL-1含药PDA平板上，7种杀菌剂对链格孢菌菌株的抑菌率均大于80%，分别为400 g•L-1氟硅唑、500 g•L-1异菌脲、80%戊唑醇、10%多抗霉素B、12.5%烯唑醇、33.5%喹啉酮和10%苯醚甲环唑。【结论】确定中华猕猴桃褐斑病由链格孢引起，400 g•L-1氟硅唑、500 g•L-1异菌脲、10%多抗霉素B和10%苯醚甲环唑对链格孢抑菌效果较强。

Identification and Pharmaceutical Screening of Brown Spot Disease on Actinidia chinensis

【Objective】The objective of this study is to identify the pathogenic fungus of a serious disease which had caused brown spot disease to Actinidia chinensis, and screen out effective chemicals for inhibition of its mycelium growth.【Method】 Isolates from diseased fruits and leaves were cultured on PDA medium and purified by single spore culture, respectively. Identification of the pathogenic fungus was carried out according to the characteristics of fungal morphology, pathogenicity and by the molecule biology identification. Eighteen fungicides were used to determine the bacteriostatic effect on that pathogen, and the toxicity regression equation of them was also established.【Result】Fungal morphological characteristics of three purified pathogenic strains from different samples were the same, and then these strains were identified to the same pathogen, Alternaria alternata (Fr.:Fr.) Keissler, by rDNA-ITS sequence alignment and BLASTn tool combined with morphology characteristics. On 10 μg•mL-1 drug-containing PDA plates, the average inhibition rate of the pathogen was more than 80% by seven kinds of fungicides which were 400 g•L-1 flusilazole, 500 g•L-1 iprodione, 80% tebuconazole, 10% multi-antimycin B, 12.5% diniconazole, 33.5% quinolinone and 10% difenoconazole, respectively.【Conclusion】It is concluded that A. chinensis brown spot disease is caused by A. alternata, and 400 g•L-1 flusilazole, 500 g•L-1 iprodione, 10% multi-antimycin B and 10% difenoconazole have a better inhibitory effect on A. alternata than others used in this research.