Differentiation of commercial strains of <Emphasis Type="Italic">Agaricus</Emphasis> species in China with inter-simple sequence repeat marker

In recent years, Agaricus mushroom production has undergone an important increase in the world. However, there is no consensus over the taxonomy of some commercial strains. So rapid and reliable methods to identify Agaricus strains are urgently needed. In this paper, six inter-simple sequence repeat (ISSR) primers were screened from 20 primers to analyse the genetic diversities of the 12 main commercial strains of Agaricus in China. The results showed that a total of 124 bands were produced, among which 80.6% was polymorphic, the similarity coefficients ranged from 0.69 to 0.98. Twelve tested strains were divided into 2 groups on the similarity coefficient of 0.75. Three Agaricus bitorquis strains were clustered in one group, and seven Agaricus bisporus strains were clustered with Agaricus strains S1 and S2 in the other group. As comparison with ISSR, intergenic spacers combined with restriction fragment length polymorphisms (IGS-RFLP) was employed to analyse genetic diversities of the tested strains by digesting IGS amplified products with restriction enzymes Hae III, Alu I, Rsa I, respectively, and IGS-RFLP cluster results were similar with those of ISSR. However, ISSR was superior to IGS-RFLP in differentiating closely related strains. It is suggested that the ISSR marker is an alternative method to differentiate Agaricus strains.