Polymorphism Analysis Of Frankia In Nodules Of Hippophae Rhamnoides Ssp. Russia

Hippophae rhamnoides ssp.Russia was introduced as cultivate variety in the north of China.It's root can fix nitrogen from atmosphere for plant growth in symbiosis with Frankia. It has extensive adaptability to poor soil and harsh environments,and it's trees have remarkable ecological effects which can increase water and soil conservation capability, effectively control water flow and soil erosion, and decrease flood disaster. However, the study on symbiotic nitrogen fixation of this species is little known.To utilize more efficiently this symbiosis, the paper focuses on genetic diversity of symbiosis with Frankia in H.rhamnoides ssp.Russia.The main results were as follows:(1) DNA was successfully extracted from 63 individuals of 5 locations, using the modified CTAB process. And DNA of nifD-nifK IGS was amplified using specific Frankia primers(FGPD807,FGPK333). The analysis of amplification results was good and feasible.(2) The PCR products of nifD-nifK intergenic spacer (IGS) were digested with HinfⅠ,HaeⅢ和TaqⅠ. 12 discernible loci are obtained from 63 samples,and 91.6% are polymorphic of these loci(PPL).Dendrogram analysis indicates the rich genetic diversity of Frankia from H.rhamnoides ssp.Russia root nodules.(3) The analysis of restriction enzyme mapping indicated that 63 samples are divided into 8 IGS types.Their distribution is uneven , some IGS type has extensive distribution and other IGS type has typical regionality.(4) The analysis of genetic distance based on Nei's showed that the genetic distance among different genotypes vary 5.72 %～64.55 % ,and phylogenetic relationship among different Frankia genotypes is not found to correlate with sites. (5) The comparative analysis based on sequences of nifD-nifK IGS indicated that size and composition of nucleotide in nifD-nifK IGS region were different,67bp and 102bp respectively.The UPGMA analysis based on sequences of the nifD-nifK IGS indicated that H.rhamnoides ssp.Russia-infective Frankia strains are all in the ClusterⅢand the diversity of this group is quite abundant.