源自江苏省的稻瘟病菌营养体亲和能力与无性重组的研究

Vegetative Compatibility and Asexual Recombination in Magnaporthe grisea from Jiangsu Province, China

将江苏省 2 0个不同小种稻瘟病菌菌株在白米玫瑰红培养基上对峙培养测定营养体亲和性 ,2 5℃、黑暗中对峙培养 18d ,在 173个配对组合中有 12 4个配对组合的菌株之间 ,通过菌丝融合在菌落交界处形成肉眼可见的菌丝融合带 ,在 4 9个配对组合不能形成明显的菌丝融合带 ,表明江苏省不同来源的稻瘟病菌菌株间存在较普遍的营养体亲和性。将分别携有抗稻瘟灵、对多菌灵敏感 (MBCsIPTr) ,以及对稻瘟灵敏感、抗多菌灵 (MBCrIPTs)标记的菌株对峙培养 ,切取菌丝融合带进行单菌丝片段分离 ,从其无性系中获得了经菌丝融合产生的携带双亲抗性标记的(MBCrIPTr)的无性重组体。在检测的 17个不同小种菌株配对的组合中 ,有 13个组合可获得无性重组体。不同配对组合菌株间无性重组频率为 0 .6 %～ 11.3%。表明营养体亲和在江苏省稻瘟病菌中发生较为普遍。

Vegetative compatibility among isolates of Magnaporthe grisea collected from different areas of Jiangsu Province and asexual recombination among compatible isolates by anastomosis were tested. Twenty isolates involving seven races from diseased rice plants were paired on polished rice rose bengal medium and incubated at 25℃ in darkness for 18 days. Out of 173 pairings tested, solid hyphal fusion lines formed by anastomosis between 124 pairings indicated that these isolates were vegetative compatible with each other. The result showed that most M. grisea isolates were vegetative compatible. Furthermore, 17 vegetative compatible pairings between monoconidial isolates with IPT rMBC s marker and isolates with IPT sMBC r marker were selected to detect the asexual recombination between the paired isolates of different races. The asexual recombinants with MBC rIPT r marker were detected in single hyphal fragment progenies in thirteen out of the seventeen pairings. The percentage of recombinants detected was about 0.6%-11.3%. Results showed that vegetative compatibility was prevailing among isolates of M. grisea in Jiangsu province in vitro . These results also suggest that asexual recombination may be an important mechanism for M. grisea to produce and maintain genetic diversity in nature.