木薯疫霉根腐病病原初步鉴定及其生物学特性测定

Preliminary Identification of a Pathogen Causing Phytophthora Root Rot Disease of Cassava and Its Biological Characteristics

2010年11月,在对海南省儋州市的木薯病害调查中发现一种根腐病。经致病性评价,分离获得病原菌。显微观察发现,菌丝无分隔,孢囊梗呈简单合轴分枝,孢子囊多顶生,倒梨形,厚垣孢子大量产生,球形、顶生。形态观察结果初步表明,其为棕榈疫霉(Phytophthora palmivora)。ITS序列分析表明,其和几株棕榈疫霉(HQ237481,HQ237478和HQ237477)的序列同源性为99%。生物学特性研究表明,OA或CMA培养基、26~30℃、p H 5、D-木糖醇、乙酸铵、光暗交替是病菌生长最适条件,菌丝致死温度为50℃,10 min。

A cassava root rot disease was f ound in Danzhou of Hainan Province during a survey in November 2010. The pathogen was isolated with following Koch's postulates. Microscopic observation results showed the mycelium wasn't separated, the sporangiophore were simple sympodial branches. Most of the sporangium were formed on the top, obpyriform. The chlamydospores were spherical, formed on the top and produced abundantly. The preliminary results showed the pathogen was Phytophthora palmivora, and the ITS sequence had homology of 99% with several sequences (e.g., GenBank Accession Nos. HQ237481, HQ237478, and HQ237477) of P. palmivora. The optimal condition for the mycelium growth included OA or CMA medium, 26℃ to 30℃ , pH 5, D-xylitol, ammonium acetate and alternative light, and the lethal temperature of mycelium was 55℃ for 10 min.