甘薯基腐病病原鉴定及生长特性测定

Identification and growth characteristics determination of sweet potato foot rot pathogens

  • 摘要: 【目的】分离鉴定浙江省宁波市宁海县甘薯基腐病病原菌,明确其生物学特性,为甘薯基腐病的预防和田间防治提供理论指导。【方法】采用组织分离法对浙江省宁波市宁海县甘薯基腐病病原进行分离,通过柯赫氏法则对病原菌进行验证;通过形态学方法及分子生物学方法鉴定病原菌种类;用菌丝培养法测定分离获得的病原菌菌株在不同培养基及不同温度、pH、氮源和碳源等环境中的生长状态,确定分离菌株的生物学特性。【结果】从甘薯基腐病样品中分离纯化获得1株菌株,标记为RF-NH,通过柯赫氏法则验证为甘薯基腐病致病菌。利用ITS、His3Cal基因的通用引物对菌株RF-NH DNA进行扩增,获得的基因片段长度分别为579、480和537 bp;系统发育进化树分析显示,菌株RF-NH与Diaporthe batatas聚类在一起;综合形态学和分子生物学鉴定结果,将菌株RF-NH鉴定为甘薯间座壳菌(D.batatas)。病原菌生物学特性测定结果显示,菌株RF-NH在15~35℃内均可生长,最适生长温度为25℃;在pH 4~12内均可生长,最适pH为4;最适培养基是SPDA培养基,最适碳源是糊精,最适氮源是硝酸钠。菌株RF-NH孢子致死温度为50℃处理10 min,菌丝致死温度为49℃处理15 min或50℃处理10 min。【结论】甘薯间座壳菌是导致浙江省宁波市宁海县甘薯基腐病的病原,该菌生长温度范围较窄,偏好25℃,适应的pH范围较宽,偏好酸性环境,最适培养基为SPDA培养基。根据甘薯间座壳菌的生长特性,在田间病害防治中可通过改变栽种环境因素以抑制病原菌的生长,实现对甘薯基腐病的防治。

     

    Abstract: 【Objective】To isolate and identify the pathogen of sweet potato foot rot disease in Ninghai County, Zhejiang Province, and to realize the biological characteristics of the pathogen, so as to provide theoretical guidance for the prevention and control of sweet potato foot rot disease in field.【Method】Pathogen of sweet potato foot rot collected from Ninghai, Zhejiang Provence was isolated through tissue isolation method and it was verified according to Koch's rule. And the species of pathogen was identified by the morphological and molecular biological method. To confirm the biological characteristics of pathogen, the growth of pathogen in different mediums, temperature, pH, carbon and nitrogen sources were measured using mycelium cultivation method.【Result】One strain of fungus was isolated and purified from sweet potato foot rot sample, marked as RF-NH. According to Koch's rule, it was verified as pathogen of sweet potato foot rot disease. DNA of strain RF-NH was amplified with general primers of ITS, His3 and Cal genes, and length of gene segments were 579, 480 and 537 bp, respectively. Phylogenetic analysis showed that strain RF-NH were clustered with Diaporthe batata. Given the results of morphological and molecular biological identification, pathogen of sweet potato foot rot disease in Ninghai, Zhejiang Provence was identified as D. batatas. Results of pathogen biological characteristic determination of D. batatas:the suitable temperature for mycelial growth of D. batatas ranged from 15 to 35℃;and the optimum temperature for growth was 25℃ suitable pH for mycelial growth ranged from 4 to 12;and the optimum pH was 4;moreover, the optimal carbon and nitrogen sources for mycelial growth were dextrin and sodium nitrate, and the optimal medium was Sweet Potato Dextrose Agar. In addition, the lethal temperature for conidium growth was 50℃ for 10 min and the lethal temperature for mycelial growth was 49℃ for 15 min or 50℃ for 10 min.【Conclusion】D. batatas is the pathogen of sweet potato rot disease in Ninghai, Zhejiang Province. The temperature range for mycelial growth of D. batatas is narrow, and 25℃ is preferable for the pathogen. The pH range is wide, and the acid environment is more suitable for its growth. The most suitable medium is SPDA medium. According to the growth characteristics of D. batatas, changing cultivation environment, adjusting soil pH, applying fertilizer scientifically and rotating crops can inhibit the growth of D. batatas, so as to realize the decrease of sweet potato foot rot disease damage.

     

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