湖北省黄连叶斑病病原鉴定及其生物学特性
Identification and biological characteristics of the pathogen causing leaf spot on Coptis chinensis in Hubei Province

为明确湖北省黄连叶斑病病原菌种类及其生物学特性，采用常规组织分离法获得病原菌菌株HL-1，通过形态学特征并结合基于ITS序列分析对菌株进行鉴定，并研究该病原菌的生物学特性，用生长速率法测定了6种杀菌剂对该病原菌菌丝生长的抑制作用。结果表明，黄连叶斑病病原菌分生孢子器黑褐色，大小为100.5~120.0 μm×175.3~210.0 μm；分生孢子色，单孢，大小为2.0~2.5 μm×4.1~5.4 μm；该菌株ITS序列系统发育进化分析结果表明，其与耧斗菜茎点霉Phoma aquilegiicola（HM222537.1）的同源性为100%，通过形态学特征及分子鉴定结果确定该菌株为耧斗菜茎点霉。该病原菌在4~25℃内均能生长，最适温度为20℃；不同光照条件对病原菌生长的影响显著差异；在供试碳（氮）源中病原菌对麦芽糖和蛋白胨的利用效果最好；菌丝的致死温度为50℃、10 min。供试6种药剂中10%苯醚甲环唑对病原菌菌丝生长的抑制效果最好，其EC50最小，为0.03 μg/mL。
In order to confirm the pathogen of leaf spot on Coptis chinensis and its biological characteristics, the strain HL-1 was isolated by tissue isolation method; the pathogen was identified with morphological characteristics and ITS sequence analysis, and the biological characteristics were also determined. The toxicities of six fungicides against the pathogen were tested. The results showed that the fungal pycnidia were black brown, 100.5-120.0 μm×175.3-210.0 μm in diameter; its conidia were colorless and monospora, 2.0-2.5 μm×4.1-5.4 μm in diameter. The analysis of ITS rDNA sequence showed that the fungus shared 100% identity with Phoma aquilegiicola (HM222537.1). The fungus was finally identified as Phoma aquilegiicola. The mycelia could grow at 4-25℃, and 20℃ was the optimum temperature；no significant differences were found in the mycelial growth between different illuminations. The optimal carbon source for mycelial growth was maltose, and the optimum nitrogen source was peptone. Hyphal viability completely lost when hyphal agar plugs were incubated at 50℃ for 10 min. The most effective fungicide was 10% difenoconazole among the six tested fungicides, with the lowest EC50 of 0.03 μg/mL．