表型与亲本不易区分的茯苓同核体菌株新类型

茯苓Wolfiporia hoelen是我国传统中药材之一,也是一种食药兼用的大型真菌,目前已规模化栽培,但由于其交配系统一直不明确,影响了种质改良。前期我们发现了茯苓的同核体,明确了茯苓的交配系统和生活史,并建立了以培养特性和分子标记区分同核体的方法,但未明确是否适用于茯苓种群的不同个体。在对多个菌株的研究中,发现了同核体表型与亲本不易区分的茯苓菌株。本研究主要以来自日本的菌株775 (NBRC 30628)为亲本,对其同核体菌株进行收集鉴定,并对同核体菌株的培养特性、交配现象和杂交等进行了研究。此类菌株的同核体菌株可通过与亲本对峙培养进行鉴定,但菌丝生长、菌落形态和吃料速度等与亲本没有显著差异,不同交配型的同核体之间交配时没有明显的交配现象。rpb2杂合位点标记可以用于鉴定该类型同核体菌株,且能验证是否交配。该类型同核体与之前发现的同核体类型之间可以进行杂交,杂交菌株可与两亲本都产生拮抗现象。该发现补充了之前建立的茯苓同核体鉴定方法,加深了对茯苓物种群体的了解,同时丰富了茯苓的育种资源。

A new type of homokaryotic strain of Wolfiporia hoelen with indistinguishable phenotypes from the parent strains

Wolfiporia hoelen, one of the traditional Chinese medicines, is simultaneously edible and medicinal. Although it has been cultivated in China for a long time and on a large scale at present, an ambiguous mating system has limited the improvement of cultivated strains. In our previous studies, the homokaryons were discovered, the mating system and life cycle of the fungus were elucidated, the methods of distinguishing the homokaryons based on culture characteristics and molecular markers were established. However, whether the methods can be used in all the W. hoelen population is undefined. In the present study, a new type of homokaryons of W. hoelen derived from Japanese strain NBRC30628 was discovered and identified. The culture characteristics, mating reaction and crossing of these homokaryons were studied. The new type of homokaryons was discriminated through antagonism with parent strain. It was found that there were no differences in growth rates on PDA and sawdust and colony morphology between the homokaryons and parent strain. No mating reaction was discovered in the mating process. The rpb2 marker was used to distinguish the homokaryons and verify the results of mating. Mating test showed that the new type of homokaryons could cross with the homokaryons previously discovered, and the hybrids could produce antagonism reactions with two parent strains. This finding supplements a distinguishing method of identifying homokaryons of W. hoelen population.