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

本研究旨在探讨香菇天然居群线粒体DNA的限制性片段长度多态(RFLP)变异、有性杂交中线粒体的遗传方式以及线粒体DNA对农艺性状的贡献。研究结果总结如下。(1)对来自不同地理种群的51个香菇野生菌株的mtDNA进行了RFLPs分析，发现各菌株的mtDNA具有较高的多态性。51个野生株的mtDNA被分成28种不同的mtDNA RFLP表型。对所有mtDNA RFLP表型之间的相似性矩阵进行UPGMA分析表明，28个mtDNA FRLP表型可分为五大类群，每一类群代表一个地理上不同的群体。这一结果表明，香菇包括一些不同的种内群体，具有遗传差异。(2)性交…的线粒体遗传方式利用mtDNA RFLPs作为遗传标记，可以检测到更多的香菇SSES。来自携带不同mtDNA RFLP表型的亲和单核体之间正反交的所有新建立的双核体都保留了其中一个单核体的mtDNA基因型，这表明线粒体的遗传主要是单亲遗传。(3)采用正反交和原生质体再生相结合的去双核化方法，可以构建各种核相同但线粒体DNA不同的新双核体，即细胞质置换双核体。(4)为了评价mtDNA对香菇农艺性状的贡献，我们检测了菌丝生长、某些同工酶的电泳酶谱、结实期类型以及来自两个参考双核体的细胞质置换双核体的子实体形态和生产力等特性。这些双核体之间的性质没有明显的差异。这表明，RFLP中不同mtDNA的替换可能不会影响香菇的农艺性状。较少

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