马铃薯早疫病菌的分离鉴定和生物学特性研究

Identification and Biological Characteristics of Potato Early Blight

采用组织分离法对重庆市巫溪县马铃薯早疫病病原菌进行分离鉴定,并对该菌的生物学特性进行研究。结果表明:重庆地区马铃薯早疫病菌丝有横隔和分支;分生孢子梗单生或丛生;分生孢子倒棒状或手雷形,大小为(46.32～156.33)μm×(11.58～28.95)μm,具纵横隔膜。结合rDNA-ITS序列分析,确定为茄链格孢菌(Alternaria sonali Sorauer)。生物学特性研究表明,光照对菌丝生长影响不显著,但黑暗条件有利于产孢;菌丝生长最适温度为27～28℃,最适pH值为6;分生孢子萌发最适温度为30℃,最适pH值为7～8。营养特性研究表明,蔗糖、果糖、乳糖、麦芽糖和淀粉都比葡萄糖更有利于菌丝生长,其中蔗糖、果糖、乳糖效果较好;甘氨酸和硝态氮能促进菌丝生长,铵态氮抑制菌丝生长。

Potato(Solanum tuberosum L.)early blight pathogen in Wuxi County,Chongqing city was isolated and identified,and its biological characteristics were studied.The results indicated that there were septate and branch hyphae in mycelium of potato early blight pathogen in Chongqing area.And the conidiophore was solitary or clustered,and the spore was of clavate or grenade shape.The size of conidia was(46.32-156.33)μm×(11.58-28.95)μm with longitudinal and latitudinal septa.Analysis of rDNA-ITS sequence of pathogen indicated that the strains were Alternaria sonali Sorauer.Studies on its morphologic characteristics indicated that light had no remarkable influence on mycelial growth,but darkness was favorable for spore-bearing.The optimum temperature for mycelial growth ranged from 27 to 28 ℃,the optimum pH value was 6.The optimum temperature for conidial germination was 30 ℃,the optimum pH value was 7-8.Studies on nutritional characteristics showed that sucrose,fructose,lactose,maltose and starch were more favorable for mycelia growth than dextrose,among which sucrose,fructose,lactose were better than carbon sources,and glycine and nitrate nitrogen could promote mycelia growth,but ammonium nitrogen could inhibit mycelia growth.