食用菌可栽培种类野生种质的评价

Evaluation for Wild Germplasm of Cultivated Mushroom Species

我国是食用菌野生种质资源丰富的国家,目前已查明自然分布可栽培野生种类93种,分布于担子菌的33个属。我国人工栽培种类近70种(变种),不同规模栽培有50种,商业规模栽培33种,分布于5目,12科,18属。与绿色植物的自养型光合作用合成有机物质相反,食用菌将植物光合作用合成的有机物分解,以体壁吸收方式摄取营养建造自身。这种生理特点的不同,导致其种质资源评价要求的不同。由于子实体形态相对于绿色植物简单,且易受环境条件的影响,常常导致以形态特征为主要依据进行分类鉴定陷入困境。另一方面,形态相似的多个可栽培近缘种在侧耳(Pleurotus)、木耳(Auricularia)、蜜环菌(Armillaria)等中广泛存在,完全靠形态特征进行分类鉴定就更加困难。因此,在食用菌可栽培种类野生种质评价中,ITS测序等成为获得菌种生物学种的常用鉴定技术。菌种的分离培养中常受到菌落形态相似真菌的污染,RAPD、ISSR或ITS测序等常用来进行菌种符合性鉴定。食用菌孢子传播的特点,使其分布地理区域广泛,地理区域的隔离产生种内的个体或群体间的差异,形成种群的多样性,常用拮抗反应进行营养亲和群(个体、菌株)的鉴定。不同区域气候和生态条件下的个体,长期的进化和对环境条件适应性的形成,导致可栽培利用的特点不同。栽培性状要通过栽培试验进行评价。栽培性状主要包括菌丝长速、温度反应、结实性、丰产性、抗性、商品形态和耐贮运性等。为了充分利用远缘优势,对于具可利用栽培性状的种质还需要与栽培菌株间的遗传距离分析,通常用生物化学和分子生物学方法进行。

There are rich in wild germplasm resources of edible mushrooms and cultivable 93 species arise in China,which belong to 33 genera in Basidiomycete. Among them,70 species were domesticated successfully and 50 species were cultivated in various scale;33 species were produced commercially,which belong to 5 orders, 12 families, 18 genera. Biosynthesis of edible mushrooms is different from autotrophic green plants which synthesize organic compounds by photosynthesis. And they are heterotrophic organisms which break down the photosynthate of plants and construct themselves by bodies absorption of nourishment penetration. This biosynthesis property results in difference of evaluation methods from green plants for wild edible mushroom germplasm. Compared with green plants, diversities of their fruiting bodies are simple in morphology and they are prone to be changed with influenced of environment conditions. It often results in confusion for the taxonomy identification based on morphology. On the other hand, taxonomy to species is more difficult based on morphology in cultivable mushrooms which have multiple relative species in the same genus, for example,Pleurotus,Auricularia and Armillaria. Therefore, ITS sequencing generally is used to identify biological species for the sample and isolates in the wide germplasm evaluation of cultivable mushrooms. RAPD （ random amplified polymorphic DNA）, ISSR （ inter-simple sequence repeats） and ITS （ internal transcribed spacers）sequencing are used as routine tools to identify isolates genuineness because the isolates are usually contaminated by other fungi similar in colony character. The spores spreading with air flow makes mushrooms to distribute in widely geographical region, and it further generates differences among the individuals or population in one species. The difference of available cultivation characters is formed in the long-term evolution with various climate and ecological conditions. Cultivation characters are evaluated in the fruiting test, which are related in growth and temperature reaction for mycelia, fruiting character, yield, resistance, commodity shape and endurance for transportation. In order to take the distant advantages,the genetic distance will be analyzed for the germplasm mate- rials compared with cultivated strains based on the test of biochemical or molecular biology.