广西莪术叶枯病病原菌鉴定、生物学特性及室内药剂筛选

Identification, biological characteristics and indoor reagents screening of pathogen causing leaf blight of Curcuma kwangsiensis

关键词:  广西莪术, 叶枯病, 病原菌鉴定, 生物学特性, 药剂筛选

Key words:  Curcuma kwangsiensis, leaf blight, pathogen identification, biological characteristics, reagent screening

摘要:

为明确引起广西钦州市的广西莪术叶枯病的病原菌,探究其生物学特性,并筛选出有效的防治药剂。该研究利用常规组织分离法对感病叶片进行病原分离,基于柯赫氏法则进行致病性测定,并通过病原菌形态特征并结合其ITS、TUB基因序列联合分析确定其分类地位,同时利用菌丝生长速率测定法研究病原菌的生物学特性及4种药剂的敏感性。结果表明:(1)根据病原菌菌落、孢子形态等特征,以及多基因联合系统发育分析确定广西莪术叶枯病病原菌为间座壳属真菌菜豆间座壳。(2)最适于该病原菌生长的培养基是PDA,最佳碳源、氮源分别是葡萄糖和蛋白胨; 25～28 ℃有利于菌丝生长,致死温度为56 ℃; pH 5～7有利于菌丝生长; 全光照有利于菌丝生长。(3)毒力测定结果表明,供试的4种药剂对广西莪术叶枯病菌均表现较强的抑制活性,其中250 g·L^-1吡唑醚菌酯EC和75%肟菌·戊唑醇WG的抑菌效果较好,EC₅₀值分别为0.055 0 μg·mL^-1和0.121 6 μg·mL^-1。综上认为,广西莪术叶枯病菌为间座壳属真菌菜豆间座壳,其菌丝生长受温度、光照、pH、碳氮源条件影响明显,250 g·L^-1吡唑醚菌酯EC和75%肟菌·戊唑醇WG可作为防治叶枯病的候选药剂。该研究结果为广西莪术叶枯病的有效防治提供了理论指导。

Abstract:

In order to identify the pathogen causing leaf blight of Curcuma kwangsiensis in Qinzhou City, Guangxi, and to explore its biological characteristics and to screen out effective reagents. In this study, pathogens were isolated from infected leaves by conventional tissue separation method, pathogenicity was determined based on Koch's rule, and their classification status was determined by morphological characteristics of the pathogen combined with the analysis ITS and TUB gene sequences. At the same time, biological characteristics of the pathogen and sensitivities of four reagents were studied by mycelium growth rate measurement method. The results were as follows:(1)Diaporthe phaseolorum was identified as the pathogen causing leaf blight of Curcuma kwangsiensis in Guangxi based on the characteristics of pathogen colony, spore morphological characteristics and multi-gene phylogenetic analysis.(2)The most suitable medium for growth of the pathogen was PDA, and the best carbon and nitrogen sources were glucose and peptone, respectively. The temperature between 25 ℃ and 28 ℃ was favorable for mycelium growth, and the lethal temperature was 56 ℃. pH 5-7 was favorable for mycelial growth. Full light was favorable for mycelial growth.(3)The results of the virulence test showed that all the four fungicides tested showed strong inhibitory activity against C. kwangsiensis leaf blight. Among them, and 250 g·L^-1 pyraclostrobin EC and 75% oximme·pentazolol WG showed the best inhibitory effect, with EC₅₀ values of 0.055 0 μg·L^-1 and 0.121 6 μg·mL^-1, respectively. In conclusion, the pathogen of leaf blight of C. kwangsiensis belongs to Diaporthe phaseolorum. The mycelial growth of D. phaseolorum is significantly affected by temperature, light, pH, carbon and nitrogen source conditions, and 250 g·L^-1 pyraclostrobin EC and 75% oximme·pentazolol WG can be used as candidate reagents to control leaf blight. The results provide theoretical guidance for effective prevention and control of leaf blight of C. kwangsiensis in Guangxi.