Correlations between the ages of Alnus host species and the genetic diversity of associated endosymbiotic Frankia strain
Nodule samples were collected from four alder species: Alnus nepalensis, A. sibirica, A. tinctoria and A. mandshurica growing in different environments on Gaoligong Mountains,Yunnan Province of Southwest China and on Changbai Mountains, Jilin Province of Northeast China. PCR-RFLP analysis of the IGS between nifD and nifK genes was directly applied to uncultured Frankia strains in the nodules. A total of 21 restriction patterns were obtained. The Frankia population in the nodules of A. nepalensis had the highest genetic diversity among all four Frankia populations; by contrast, the population in the nodules of A. mandshurica had the lowest degree of divergence; the ones in the nodules of A. sibirica and A. tinctoria were intermediate. A dendrogram, which was constructed based on the genetic distance between the restriction patterns, indicated that Frankia strains from A. sibirica and A. tinctoria had a close genetic relationship. Frankia strains from A. nepalensis might be the ancestor of Frankia strains infecting other Alnus species. From these results and the inference of the ages of Alnus host species, it is deduced that there was a co-evolution between Alnus and its microsymbiont Frankia in China.
作 者： Dai yumei Zhang Chenggang Xiong Zhi ZHANG Zhongze 作者单位： Dai yumei(Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China;Graduate School of the Chinese Academy of Sciences, Beijing 100039, China)Zhang Chenggang,ZHANG Zhongze(Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China)
Xiong Zhi(School of Forest Resources, Southwest Forestry College, Kunming 650224, China)
刊 名： 中国科学C辑（英文版） SCI 英文刊名： SCIENCE IN CHINA SERIES C(LIFE SCIENCES) 年，卷(期)： 2005 48(z1) 分类号： Q7 关键词： Frankia Alnus genetic diversity co-evolution