稻瘟病菌无性重组体若干生物学性状的研究  

Several biological characteristics of asexual recombinants of Magnaporthe grisea

作　　者：王艳丽[1] 张正光[1] 陆凡[1] 郑小波[1] 

机构地区：[1]南京农业大学农业部病虫监测与治理重点开放实验室,江苏南京210095

出　　处：《南京农业大学学报》2003年第2期33-37,共5页Journal of Nanjing Agricultural University

基　　金：国家自然科学基金资助项目 (3 9970 0 2 6);高校骨干教师基金;国家高技术研究发展计划 (863计划)(2 0 0 2AA2 413 11)

摘　　要：将营养体亲和的、携带抗药性标记的稻瘟病菌不同小种的菌株对峙培养 18d后 ,对交界处产生的菌丝融合带进行单菌丝片段群体分离 ,从 5个配对组合中获得的 75个无性重组体中筛选出 2 0个稳定的无性重组体。对它们的生长速率、产分生孢子能力、分生孢子萌发率和致病力等生物学性状进行测定 ,结果显示 :供试重组体在 5种常规培养基上均生长良好 ,部分重组体的生长速率显著超过亲本 ;在玉米稻汁培养基上均具有较好的产孢能力 ,产孢量每皿 (直径 6 0mm)为 1 0 8× 10 5～ 8 18× 10 6个 ,部分菌株产孢量显著超过亲本 ;分生孢子萌发率为 6 5 %～ 97% ,与亲本无显著差异 ;大多数重组体均可对水稻致病 ,且无性重组还导致毒性发生复杂的变异。来自同一配对组合的无性重组体后代在日本 13个已知抗性基因品种上显现出与双亲不同的毒性表型 ,部分重组体丧失了亲本所具有的毒性 ,而有部分重组体表现出亲本所没有的毒性 ,提示双亲的遗传物质在重组体内存在复杂的互作关系。研究结果表明 ,稻瘟病菌不同小种菌株间通过菌丝融合产生的无性重组体具有较强的适生性 ,提示无性重组可能是稻瘟病菌遗传多样性产生的重要途径之一。The vegetative compatible isolates between races of Magnaporthe grisea with different chemical resistant markers were paired on plates containing polished rice rose bengal agar and incubated at 25 ℃ in darkness for 18 days. The populations of single hyphal fragment isolates were established from the hyphal fusion line formed between the interracial isolates paired. The 75 asexual recombinants were obtained from 1 132 single hyphal fragment isolates of 5 interracial pairings, from which 20 stable asexual recombinants carried stable MBC r IPT r marker after storage at -20 ℃ for 3 months were selected and their biological characteristics were tested in growth rate, sporulation, spore germination rate and virulence. The results showed that all of asexual recombinants grew well on the five kinds of common fungal media, part of which were higher significantly than their parents in growth rate. The sporulation capacity of asexual recombinants was strong with amount of spore production at 1 08×10 5 8 18×10 6 /disc ( d =60 mm),and some recombinants produced much more conidia than their parents on the medium containing corn and rice stalk juice. The spore germination rate of asexual recombinants tested was 65%97%, which was similar with the parents.After inoculated on 13 Japanese rice cultivars harboring known resistance genes,most of recombinants shared different virulence spectrums compared with their parents, which indicated that complicate interaction might occur between the genetic materials from their parents in asexual recombinants. These results showed that the asexual recombinants were of strong fitness in vitro , indicating that the asexual recombination might be an important role in producing and maintaining the genetic diversity in the wild population of M. grisea .

关 键 词：稻瘟病菌 无性重组体 生物学性状 生长速率 分生孢子萌发率 致病力 产孢能力 遗传多样性 变异 

分 类 号：S435.111.4[农业科学—农业昆虫与害虫防治]