黑龙江省高粱炭疽病致病真菌分离与鉴定

Isolation and identification of pathogenic fungi causing sorghum anthracnose in Heilongjiang province

摘要:

【背景】黑龙江省高粱炭疽病是目前主要的高粱病害之一，严重影响高粱的产量与品质。【目的】明确黑龙江省高粱炭疽病的病原种类。【方法】采用组织分离法与单孢纯化法获得高粱炭疽病病原纯培养物。通过柯赫氏法则证病后，利用培养物菌落形态、产孢结构、分生孢子形态及大小等形态学特征，同时结合rDNA ITS序列特征对病原物进行鉴定。【结果】柯赫氏法则验证结果表明，分离自不同地区的3个分离株D13、H4和Z24是高粱炭疽病的致病真菌。形态学观察表明，3株菌在PDA培养基上在28 °C形成的菌落生长速度为7.3?12.3 mm/d，菌丝白色、灰白色至灰色，菌落浅黄色至橘黄色；刚毛直立，基部膨大，褐色或深褐色，有3?5隔；分生孢子梗直接从菌丝体上产生，无色无隔，短，直立或稍弯，不分枝；分生孢子单胞，镰状，向两端渐尖，表面光滑，无色，有的具油球；附着胞从菌丝顶端或菌丝体产生，顶端膨大，褐色或深褐色，近球形、卵球形、椭圆形或纺锤形，边缘光滑、裂片、多裂片或深裂片。分离株D13、H4和Z24获得的rDNA ITS序列登录号分别为MW040055、MW040057和MW040056。基于rDNA ITS序列构建的系统发育树发现，分离株D13、H4和Z24均与高粱炭疽菌(Colletotrichum sublineola)相聚一群。【结论】黑龙江省引起高粱炭疽病的病原真菌为高粱炭疽菌。

Abstract:

[Background] Sorghum anthracnose in Heilongjiang province is one of the main sorghum diseases, which seriously affects the yield and quality of sorghum. [Objective] To definitize the pathogen species of sorghum anthracnose in Heilongjiang province. [Methods] The pure culture of pathogenic fungi causing sorghum anthracnose was obtained by tissue separation and single spore purification. The isolated pathogenic fungi were confirmed by Koch’s rule. The morphological characteristics of colony, sporulation structure, morphology and size of conidia, were used to identify the pathogen combined with rDNA ITS sequence characteristics. [Results] Three isolates D13, H4 and Z24 isolated from different regions were pathogenic fungi of sorghum anthracnose by Koch’s rule. Morphological observation showed that the colony growth rate of 3 strains on PDA medium (28 °C) was 7.3?12.3 mm/d, the hyphae was white, grayish white to grayish brown, and the colony was light yellow to orange. Setae erected and its base distended, were brown or dark brown, with 3?5 grids. Conidiophore generates directly from hypha, colorless and eseptate, short, erected or slightly curved, unbranched. Conidia are unicellular, sickle, acuminate to both ends, smooth, colorless, sometimes with an oil ball. The appressorium produced from the apex of the hyphae or mycelium, the apex is dilated, with color of brown or dark brown, subglobose, ovoid, elliptic or spindle-shaped and its margin was smooth, lobes, more lobes or deep lobes. The rDNA ITS sequence accession numbers obtained from isolated D13, H4 and Z24 were MW040055, MW040057 and MW040056, respectively. The phylogenetic tree based on rDNA ITS sequence found that the D13, H4 and Z24 of the isolates were together with Colletotrichum sublineola. [Conclusion] The pathogen causing sorghum anthracnose in Heilongjiang province is C. sublineola.