Contribution of mitochondrial DNA to agronomic characters in the shiitake mushroom, Lentinula edodes

本研究旨在探讨香菇（Lentinula edodes）自然群体线粒体DNA（mtDNA）的限制性片段长度多态性（RFLP）变异、有性杂交的线粒体遗传方式以及mtDNA对农艺性状的贡献。结果总结如下。(1)通过对来自不同地理种群的51个香菇野生菌株的mtDNA RFLP分析，发现香菇的mtDNA在不同的地理种群间具有高度的多态性。来自51个野生菌株的MtDNA被分配到28个不同的mtDNA RFLP表型。UPGMA分析表明，28个mtDNA RFLP表型可分为5个大的类群，每个类群对应一个地理上不同的群体。结果表明，香菇存在明显的种内类群，且存在遗传分化。(2)有性杂交的线粒体遗传方式 ...更多信息 以线粒体DNA RFLP为遗传标记，研究了香菇的遗传多样性。所有新建立的双核体之间的相互杂交兼容的单核体携带不同的mtDNA RFLP表型保留的mtDNA基因型的单核体之一，这表明线粒体遗传主要是单亲的。(3)利用正反交和原生质体再生相结合的方法进行去双核化，可以构建出核相同但mtDNA不同的各种新的双核体，即胞质置换双核体。(4)为探讨线粒体DNA对香菇农艺性状的影响，对香菇的菌丝生长、同工酶电泳图谱、结果期类型、子实体形态和产率等性状进行了研究。这些双核体的性质没有明显的差异。这表明，在RFLP上不同的mtDNA的替换可能不会影响香菇的农艺性状。少

The purpose of this study was to examine restriction fragment length polymorphism (RFLP) variability of mitochondrial DNAs (mtDNAs) in natural populations of Shiitake, Lentinula edodes, the mode of mitochondrial inheritance in the sexual cross, and also the contribution of mtDNA to the agronomic characters. The results are summarized as follows. (1) By a survey of mtDNA RFLPs in 51 wild strains from different geographical populations of L.edodes, its mtDNA was found to be high polymorphic from strain to strain. MtDNAs from the 51 wild strains were assigned to 28 different mtDNA RFLP phenotypes. UPGMA analysis on a similarity matrix calculated between all pairs of mtDNA RFLP phenotypes showed that the 28 mtDNA FRLP phenotypes could be divided into five major groups, each of which accommondates a geographically distinct population. The result suggests that L.edodes includes some distinct intraspecific groups with genetic divergence. (2) The mode of mitochondrial inheritance in sexual cro … More sses of L.edodes was examined by using mtDNA RFLPs as genetic markers. All newly established dikaryons from reciprocal crosses between compatible monokaryons carrying different mtDNA RFLP phenotypes retained mtDNA genotype from one of the monokaryons, suggesting that mitochondrial inheritance is principally uniparental. (3) By using a procedure combining the methods of reciprocal crossing and protoplast regeneration for dedikaryotization, we could construct various new dikaryons which have identical nuclei but different mtDNA,namely cytoplasm-replaced dikaryons. (4) To evaluate the contribution of mtDNA to agronomic characters of L.edodes, we examined various properties such as hyphal growth, electophoretic zymograms of some isoenzymes, fruiting-time type, and fruitbody morphology and productivity of cytoplasm-replaced dikaryons derived from two reference dikaryons. No apparent difference was observed in the properties among these dikaryons. This suggests that the replacement of mtDNAs different in RFLP may not influence the agronomic characters of L.edodes. Less