稻曲病两个白化菌株的分离与生物学特性

The isolation and biological features of two albinotic isolates of Ustilaginoidea virens

为了筛选带有自然标记的稻曲病菌菌株,2010年从浙江省象山县和陕西省勉县采集和分离到2个稻曲病白化菌株,ZJa0201和SXa0101。它们在PSA培养基上的生长速度约为其他稻曲病菌株的3倍,未见产生厚垣孢子;在PS培养基上只能产生少量分生孢子。rDNA-ITS和rDNA-IGS序列分析表明,两个白化菌株也与稻曲病菌已知所有菌株的ITS序列同源性高于99.6%;rDNA-IGS序列也属于最为常见的类型,含有2个77bp的重复单元序列。由此推断,这两个白化菌株属于稻曲病菌产孢退化的突变体。白化菌株在PSA上培养30d后,菌落上可形成不成熟的类菌核组织,紫外线照射能够促进类菌核的形成;该菌核体积较小不成熟,不能萌发产生子囊孢子。

Two false smut balls potato sucrose isolates of Ustilaginoidea virens with natural marker, ZJa0201 and SXaOIO1, were obtained from albinotic of rice. The albinotic isolates grew rapidly and reached about 3 times the growth speed of wild isolates in agar （PSA） medium, and no chlamydospore was detected. Sporulation of the albinotic isolates decreased significantly in PSA medium. The analysis of rDNA-ITS sequences showed that they shared 99.6% similarity to the known wild isolates of U. virens, and their rDNA-IGS sequences belonged to the most common type, consisted of 2 repetitive units of 77bp in the central various region. It is suggested that these albinotic isolates were the mutants of sporulating degeneration ofUstilaginoidea virens. The albinotic isolates could produce immature sclerotia in 30 days in PSA and UV irradiation could promote the formation of selerotia. The immature sclerotia could not germinate.