SSR标记在毛木耳种质资源遗传多样性研究中的应用

本研究利用基于毛木耳全基因组开发的SSR标记对27份毛木耳菌株（野生14株、栽培13株）的遗传多样性进行分析。首先随机选取3个菌株（2个野生菌株、1个栽培菌株）的DNA为模板,从144对SSR引物中筛选出扩增条带清晰、稳定性强、多态性丰富的引物24对。24对SSR引物共检测到116个多态性SSR片段,每对引物的多态性片段有3-7个,引物平均检测效率为4.83个,Shannon’s遗传多样性指数范围是0.866-1.885,多态性位点比率100%。供试菌株遗传相似系数范围是0.618-0.971,说明毛木耳种质资源具有丰富的遗传多样性。野生菌株与栽培菌株间平均遗传相似系数分别为0.746、0.779,说明毛木耳野生菌株遗传多样性更为丰富。经聚类分析,在遗传相似系数为0.680时,可将供试菌株分为无色（白色）类群Ⅰ和有色（浅黄色到红褐色）类群Ⅱ。遗传相似系数为0.704时,可将供试菌株中栽培菌株和野生菌株明显区分（14株野生菌株均在类群Ⅱ-2中,13株栽培菌株分别在类群Ⅰ和Ⅱ-1中）。本研究表明基于全基因组的SSR标记能从分子水平上揭示各菌株间的遗传差异,丰富毛木耳遗传多样性的研究手段,并为进一步进行毛木耳的品种选育、遗传学研究等提供有力手段。

Application of SSR markers in evaluating the genetic diversity of Auricularia cornea germplasm resources

The genetic diversity of 27 strains of Auricularia cornea (14 wild strains, 13 cultivated strains) was analyzed by using the SSR markers developed based on whole genome sequence. Using the DNA of 3 strains randomly selected (2 wild strains and 1 cultivated strain) as template, 24 pairs of primers with clear amplification bands, strong stability and rich polymorphism were screened from 144 pairs of SSR primers. In total, 116 alleles were detected by 24 pairs of SSR primers. The number of alleles amplified by each pair of primer ranged from 3 to 7. The average detection efficiency was 4.83 alleles/primer. Shannon’s genetic diversity index was 0.866-1.885, and the polymorphic locus ratio was 100%. The genetic similarity coefficient (GS) of the tested strains ranged from 0.618 to 0.971, suggesting that the germplasm resources of A. cornea were rich in genetic diversity. The average GS of wild strains and cultivated strains were 0.746 and 0.779, respectively, indicating that the genetic diversity of wild strains was more abundant. Cluster analysis showed that the tested strains were divided into colorless (white) group I and colored (light yellow to reddish brown) group II when GS was 0.680. When GS was 0.704, the cultivated strains and wild strains could be clearly distinguished (14 wild strains were in group II-2, and 13 cultivated strains were in group I and group II-1). This study demonstrated that SSR markers based on the whole genome could reveal the genetic differences among strains at molecular level, facilitating breeding and genetic studies of A. cornea.