稻瘟病菌营养体亲和配对筛选及其亲和能力遗传

 在白米玫瑰红培养基上对江苏省的稻瘟病菌Magnaporthe grisea(Hebert) Barr.不同小种间营养体亲和菌株配对组合进行了筛选。当不同小种的菌株对峙接种,在21±1℃、黑暗中培养18 d后,部分配对组合的菌落交界处出现一条肉眼明显可见的菌丝融合带,且具有稳定的重复性。出现菌丝融合带的配对菌株在玻璃纸上对峙微培养2~3 d后,镜检观察到菌丝融合现象普遍存在;未出现明显菌丝融合带的菌株组合经对峙微培养,菌丝融合现象未见或较少。从ZA₄₉、ZG₁、ZF₁和ZD₁ 4个小种的12个菌株中筛选出3对营养体亲和性强的小种间菌株配对组合。以所选菌株为亲本建立单分生孢子无性系,测定营养体亲和能力在单孢后代的遗传。结果是,营养体亲和能力在单孢后代遗传不稳定,与另一亲本的单孢株配对产生融合带的百分率为53%~74%之间。进一步研究发现,来自同一个分生孢子不同细胞的单芽管株与配对菌株的营养体亲和能力相同;亲和能力在单芽管株的单孢株后代继续发生分离。

SELECTION OF VEGETATIVE COMPATIBLE PAIRS AND INHERITANCE OF COMPATIBILITY IN Magnaporthe grisea

Vegetative compatible pairs between races of Magnaporthe grisea were selected from isolates obtained from Jiangsu province. Each pair of test isolates were placed across a diameter of a plate containing polished rice rose bengal agar and incubated at 21±1℃ in darkness for 18 days. A solid line were observed between colonies of vegetative compatible isolates. Three compatible pairs were screened out from 144 pairings among 12 isolates of 4 races. When the isolates that formed a hyphal fusion line were inoculated on a cellophane membrane on water agar with a distance of 0.5-0.7cm, hyphal fusion was frequently observed under microscope. Less or no fusion was observed in pairings that did not form the solid fusion line. Results showed that pairings with high vegetative compatibility could be easily screen out on polished rice rose bengal agar. However, pairings with weak compatibility were hard to detect by this method. Results also showed that the vegetative compatibility of isolate in each selected pair was stable when the tested isolate was sub cultured by mass transfer, but segregate in its single conidium progeny. Further study showed that there is no variation between vegetative compatibility of two single germ tube isolates from different cells of a single conidium. However, compatibility of one of these isolates segregated again in its single conidium progeny derived from one of the single-germ-tube isolates.