采用RAPD和ISSR标记探讨中国疣粒野生稻的遗传多样性

Assessment of Genetic Variation of Oryza granulata Detected by RAPDs and ISSRs

用随机扩增多态DNA (RAPD)和inter_简单重复序列 (ISSR)标记对分别来自中国海南和云南 2 0个居群的疣粒野生稻 (Oryzagranulata (NeesetArn .exWatt.) )混合样品 ,以及海南 (M5 )和云南 (M2 7) 2个居群各 2 0个植株的遗传多样性进行了检测。在混合取样的居群中 ,2 0个RAPD引物和 12个ISSR引物分别扩增出 2 0 9和 12 2条带 ,多态条带比率 (PPB)分别为 6 4.11%和 72 .95 %。对于分单株取样的居群 ,在M5中 ,两种标记分别扩增出 146和 95条带 ,PPB值分别为 2 1.48%和 34 .78%。在居群M2 7中 ,则分别扩增出 15 1(PPB =17.2 2 % )和 94(PPB =19.15 % )条带。结果表明 ,中国的疣粒野生稻在物种水平的遗传多样性较低 ,其遗传变异主要存在于海南和云南两地之间 ,而在居群内的遗传多样性水平很低。基于Jaccard遗传相似性系数的UPGMA聚类和基于多态条带表型的主成分分析 (PCA)都将中国的疣粒野生稻分为来自海南和云南两类 ,两地间该物种的平均遗传相似性分别为 0 .5 96(RAPD)和 0 .5 11(ISSR) ,其间产生了相当程度的遗传分化。对比RAPD和ISSR在PCR反应中的稳定性和检测变异的能力表明 ,对于实验条件的稳定性而言ISSR优于RAPD ,且总的来说ISSR能检测到比RAPD更多的遗传变异。Mantel检测表明 ,在物种水平 。

Random amplified polymorphic DNA (RAPD) and inter_simple sequence repeat (ISSR) methods were applied to detect genetic variation of 20 bulking samples and two individually sampled populations of Oryza granulata (Nees et Arn. ex Watt.) from China (M5 from Hainan Province and M27 from Yunnan Province). For the bulking sampled populations, 20 RAPD and 12 ISSR primers generated 209 and 122 bands, of which 134 (64.11%) and 89 (72.95%) were polymorphic respectively. For population M5, 146 and 95 bands were generated with 21.48% and 34.78% being polymorphic (PPB). For population M27, 151 (PPB = 17.22%) and 94 (PPB = 19.15%) bands of RAPD and ISSR were obtained. The results indicated that the level of genetic variation of O. granulata was lower than other species detected in the genus Oryza. UPGMA cluster based on genetic similarity and principle component analyses (PCA) based on band patterns divided the populations into two groups corresponding to their sources, which revealed that the majority of genetic variation of O. granulata occurred between Hainan and Yunnan. Consequently, more populations of the species should be considered for a reasonable conservation management. Comparison between the two marker systems showed that ISSR was better than RAPD in terms of reproducibility and ability of detecting genetic polymorphism. Mantel test revealed that the goodness of fit between them was significant (r=0.917, t= 12.718 ) when detecting genetic diversity at species level, but was poor at population level (r<0.200). The discrepancy was considered as the facts that different fragments were targeted by RAPD and ISSR, and that evolutionary process of O. granulata varied at different hierarchical levels.