Multilocus Squence Typing Of Leuconostoc Mesenteroides From Different Samples In Tibet Plateau

Leuconostoc mesenteroidesis a species of Leuconostocgenus. It contains four subspecies: L.Mesenteroidessubsp.Mesenteroides,L.mesenteroides subsp. Dextranicum,L. mesenteroides subsp. Cremoris and L. mesenteroides subsp. Suionicum. In this study,41 Leuconostoc mesenteroidesstrains which form QianghaiTobet Plateau area and 4 standard strains were analyzed by multilocus sequence typing to study genetic polymorphism and evolutionary, so as to explore the relationship of strains and isolate samples or separate regions.The nucleotide sequence of the housekeeping genes(pyrG, groEL, rpoB, recA, uvrC, murC, carB, pheS) were squenced in both directions. Allele maps drawn after splicing and checking the nucleotide sequence, determining the sequence of different sequence type and analysising the G+C content, DNA polymorphism, dn/ds.45 Leuconostoc mesenteroides strains produced a total of 25 ST,the diversity up to 55.6%.The 4 standand strains were different, all corresponded to a unique ST type. The 16 strains isolated from the dairy products, forming 10 ST type, and the diversity ratio reached 62.5%. 25 strains isolated from plants producing 11 different ST types, and the diversity ratio was only 44%.In 25 STs,ST8, ST17, ST19 which contains a maximum 4 Leuconostoc mesenteroides strains, each diversity was as high as 8.9%. ST9, ST10, ST13 and ST14 contained 3 strains, 6.7%.ST7, ST11 and ST12 each contained 2 strains, proportion was 4.4%. The rest of ST type was unique,that is one ST type corresponded to astrain.These STs formed 4 groups after eBURST analyzing, and 15 STs was unique type. One of the 4 groups was called CC complex, namely CC9,three were double complex. ST9 was the center of the CC9, There fore ST9 was considered to be more primitive sequence type. The double complex were ST18 and ST19, ST8 and ST25, ST6 and ST13,respectively.By minimum spanning tree and clustering analysis, In this study, the strains from same Qinghai-tibet plateau, didn’t show a single aggregation. That illustrating the relationship between the isolated areas and strains was relatively weak. Most strains presented positive correlations with the samples, the samples of the same kind of separation of representative strains were close relatives.