西藏设施西(黄)瓜根腐病的分离与鉴定

Isolation and identification of root rot pathogens on protected cultivation watermelons and cucumbers in Tibet

【目的】明确西藏设施西(黄)瓜根腐病原的种类和生物学特性,为西藏设施瓜类根腐病的防治提供科学依据.【方法】对从西藏设施西(黄)瓜根部病健交界处分离到的2株真菌进行单孢分离、致病性测定、ITS序列分析、不同温度下PDA培养基上培养并定期测量菌落直径、含不同碳氮源的培养基上培养,定期测量菌落直径.【结果】西藏设施西(黄)瓜根腐病原菌为茄镰孢菌(Fusarium solani).该菌在15~40℃均可生长,最适温度为30℃;该菌对供试的13种碳源和13种氮源在培养基上均可利用,但在以乳糖为碳源的培养基及以碳酸铵和精氨酸为氮源的培养基上生长速率显著低于与对照(P<0.05),在分别以树胶醛糖和甘露糖为碳源的培养基及以硝酸钠和组氨酸为氮源的培养基上生长速率显著高于对照.【结论】茄镰孢菌(Fusarium solani)在不同碳氮源培养基上菌落形态有差异.以乳糖为碳源的培养基及以碳酸铵和精氨酸为氮源的培养基对该菌有明显的抑制作用,分别以树胶醛糖和甘露糖为碳源的培养基及以硝酸钠和组氨酸为氮源的培养基对该菌呈明显的促进作用.

[Objective] To understand the species and biological characteristics of root rot pathogens of protected cultivation watermelons and cucumbers in Tibet. [Method] Single spore isolation,pathogenicity test,and ITS sequence analysis were carried out on 2 strains of fungi isolated from the junction between diseased and healthy of watermelon and cucumber roots. The colony diameters of pathogens were determined on PDA medium contained various carbon and nitrogen sources at different temperatures. [Result]The isolated pathogen was identified as Fusarium solani. The fungi grew at the temperature ranging from 15 ℃ to 40 ℃ ,with the optimum temperature at 30℃. The pathogen utilized the 13 carbon sources and 13 nitrogen sources in media;however, the growth rates significantly decreased in medium with lactose, ammonium carbonate and arginine when compared with the control （P〈O. 05）. The growth rates significantly increased in media with arabinose,mannose, sodium nitrate and histidine when compared with the control.[Conclusion] F.solani shows different colonial morphologies in media with various carbon and nitrogen sources. Media with lactose, ammonium carbonate and arginine notably inhibit the growth of the fungi,while media with arabinose,mannose, sodium nitrate and histidine markedly promote the growth.