Development Of SSR And AFLP Markers About Panax Ginseng

Panax ginseng C.A Meyer is a famous and precious Chinese herbal medicine. The aims of present study are to develop UGMS markers; to characterize the distribution of SSR in transcriptional region of P. ginseng; and to compare the distribution frequency, general-utility of polymorphism between UGMS and G-SSR. At the same time, we also try to establish appropriate AFLP markers for P. ginseng. All the results of this study will lay a foundation for future identifications and genetic map constructions of P. ginseng. Main results are as following:1. A data set of 7 649 expressed sequence tags (ESTs) of P. ginseng downloaded from NCBI was assembled to obtain the unigenes. SSR-containg unigenes and genomic were selected to characterize the SSR distribution in ginseng genome. A total of 4 869 unigenes with a length of 2.72 Mb were predicted. From 488 SSR-containing unigenes (10.02%),724 UGMS were identified with a density of 1 per 3.75 kb of unigenes. Dinucleotide repeats (48.06%) were the most abundant followed by mono (29.28%) and tri-nucleotide repeats (19.06%). The motifs of AT/TA and AAG/CTT were mostly distributed in untranslated region and protein coding region respectively.The SSR shows higher frequency in ginseng and the most abundant motif is dinucleotide.2. A set of UGMS and G-SSR primers was designed to amplify genomic DNA of P. ginseng and other Araliaceae species. Among the 100 UGMS and 44 G-SSR primer pairs,86 and 44 showed amplications in a set of 9 ginseng accessions. Polymorphisms between the accessions were found to be 42.0% and 43.2%, respectively. The transferability of ginseng UGMS marker to P.guinquefolius, P.notoginseg and E.senticosus was 100%,87.2% and 75.6%, while 95.5%,72.7% and 40.9% for G-SSR, respectively.The distribution of UGMS was non-random with respect to different genie regions. UGMS markers detected a lower polymorphism but a higher level of transferability than those derived from genomic SSR.3. DNA extraction method of improved CTAB and optimal enzyme cut time of 4-6 hours have established;The result through AFLP indicated that 64 PstⅠ/MseⅠcombinations amplified a total of 3 545 AFLP fragments with an average of 55 fragments, the amplified polymorphic fragments were 1 312 during four Araliaceae species. The number of amplified fragments and the number of polymorphic fragments was in positive linear correlation; GC content of AFLP primer combinations affects the number of amplified fragments and the number of polymorphic fragments, indicating negative linear correlation between them. In one word,16 primer combinations were found to amplify nuclear DNA of P. ginseng, properly.