| Flax is an important economic crops, how to improve the efficiency of retting isone of the hot topics of research in flax industry currently.The bacterial diversities of BeiAn, HuLin, MingShui, SunWu and ShuangChengflax retting systems in HeiLongjiang province were studied by using of DenaturingGradient Gel Electrophoresis. In order to lay the practical fundament for the researchof the functional bacteria in the flax system, the article established a DGGE detectingplan to research the bacteria varieties in the laboratory: Firstly, in order to understandthe variations discipline, find the the dominant flora and contrast with the results of thetraditional methods, the bacterial diversity in flax retting system is analyzed byPCR-DGGE; Secondly, the most dominant bands e and the most varied strengths ofthe band d are recovered, cloned and sequenced, through compared with the knownsequences in Genebank database by use of Blast tools, the highest homology with theDNA sequences are identified, at last phylogenetic trees are constructed.Using DGGE method to analyze the bacterial diversity, DGGE bands wereseparated obviously by the gel concentration of 6.5%, 25%-55% denaturant gradient inthe range between 60℃temperature and 150V electrophoresis about 200～220min.There were some differences between the traditional training method and DGGEmethod in analysis of bacterial diversity; there were 4～5 kinds of different strains atthe very least; because of the existence of c and g bands which were not dominant inthe flax retting system and other reasons, BeiAn was realized to be the most particulararea; Generally speaking, e bands was the most dominant one in all the samples, thenfollowed f bands; d bands was the most variable one in all dominant bands; the index(H) of different time was not exactly the same; The analysis of the observation ofcluster indicated that the index (H) in 52 hr in every retting systems had the greatest difference with the others; the relation between e bands and Pseudomonas were moresimilar, the similarity was between 84% to 91%, were regarded as one group; therelation between d bands and Pantoea, Bacillus megaterium, uncultured bacteriumand unidentified bacterium were more similar, their similarity were up to 100%; therewere some sequences which were low in matching other sequences in Genebanknamed unknown bacterium.In this experience, we conclude as follows: firstly, the flora structure in the flaxretting system is not very rich and similar with each other, there are only 4～5 bacteriatypes at least in a flax retting system; secondly, the representability of c, g bands inBeiAn flax retting system are not dominant flora in the whole systems; thirdly, theflora of e bands represented is the most dominant flora in almost every flax rettingsystems and the flora of d bands represented is the most different flora in almost everyflax retting systems, it illustrates obvious succession concurs in this system; then therewas the greatest difference between the structure of the sample in 52 hr and others; atlast, Pseudomonas is the most dominant bacterial type in the retting section comparingwith Pantoea, Bacillus megaterium, uncultured bacterium, unidentified bacterium andunknown bacterium.In the future research, it is necessary to do the clone test to all DGGE bands, andusing different molecular biology methods to measure the varieties of themicroorganism in the flax retting system. Only in this way can the states of thebacteria in the flax retting system recognize more roundly and fully. In addition, in theproduction process, we can control the process of retting through detecting andcontrolling the dominant flora especially the functional flora, to enhance fiber strength,fiber rate and to shorten the retting time, then a theoretical basis is provided toimprove and widespread the bacteria retting technology and retting liquid reuse. |
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