| Thirty-two cool season cultivars which were wildly cultivated in China and two wild fruitbodies of L. edodes.were selected in this study. Their genetic similarities were analyzed by cultivation character, nucleotide sequences analysis of ITS regions of rDNA, RAPD and ISSR. The results were as following:1. Based on the data of ITS (ITS-1 and ITS-2, including the 5.8S rDNA) analysis, all the cultivars' sequence identities were 98.49%, in which 868,HUNONG3,QIN19 and XIANG66 had the same sequence with YEXIANG11,QINGKE20,867,and 241-4. All cultivars of shiitake were divided into four groups. The strains with different name had the identical sequences and were clustered together, such as 868, HUN0NG3, QINXIANG19, and XIANG66; YEXIANG11, QINKE20, 867, 241-4. On the contrary, HUA939,939 and L939 had the same name, but 5bp differences were existed in ITS sequences. Comparing the ITS sequences of all the cultivars with the ITS sequences of wild strains from GenBank, it indicated that the wild strains and the cultivars belonged to two branches, showing inheritance differences existed between them. Among the cultivated strains, there were highly similar inheritance, and no relationship between the inheritance and region. Furthermore, 32 cultivars strains had few gene types.2. Genome DNA of all strains was analyzed by RAPD with 9 random primers. A total 113 RAPD bands were amplified by using 9 random primers, among which, 83.19% were found to be polymorphic, with 13 bands per primer in average. The lengths of the amplified fragments were from 200bp to 2500bp, such as primer A04 amplified 868 and obtained 7 bands, the length of which were 400~2300bp. Based on 9 DNA fingerprints, 34 strains which were tested had the genetic difference, and could been distinguished. It confirmed that RAPD technology could be used to detect and identify edible mushroom strain fast and accurately. The results of dice similarity coefficient and clustering analysis showed that wild fruitbodies and cultivars existed distinguished inheritance differences. However, the dice similarity coefficient were from 0.50 to 0.70. The strains of HUA939,939,and L939 were in the same branch all the time, so it indicated that they may be synonym.3. 8 primers were selected from 100 ISSR primers used to amplify. A total of 98 ISSR bands were amplified with 8 primers, and 89.80% of which were found to be polymorphic. The results revealed that there were high genetic diversities among all the strains, such as allthe strains obtained 13 bands amplified by primer 812. It also showed that ISSR amplified print could distinguish the different gene types efficiently which could provide a fast and effective technique and scientific basis for strain identification of L. edodes.4. Thirty-two strains had differences in mycelium growth rates, growing trend of mycelium, colonial monphology, cultivation test and so on. Mycelium growth rates were the same in the plate experiment and in the bottle experiment. So mycelium growth rate can be used as an important standard to determine whether the strains can be cultivated in actual production. But the same strains represented different physiological characters in different media, such as L26 grew faster in petri dish than in bottle.5. Most of the strains had antagonistic line. It implicated that there were genetic diversities among the strains. Few apparent antagonism were detected among the rest strains, for example strains 867 and XIANG66, which indicated that a high similarity existed.
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