| Microorganisms play a very important role in the process of tobacco aging.The use of microorganisms to mellow tobacco can significantly improve its fermentation quality,reduce the macromolecular substances,make the smoke full and mellow,increase its aroma,and make the aftertaste pure and comfortable.In this study,the rhizosphere soil of the main tobacco planting areas in Yunnan Province were used.After high-throughput sequencing,the diversity of rhizosphere microbial community in different areas was revealed through analysis.At the same time,the aged flue-cured tobacco leaves in Yunnan,Zimbabwe,Fujian,Guizhou,Zhengyu,Shiyan in Hubei and Chenzhou in Hunan were used as well as the fresh tobacco leaves and soil in the main tobacco planting areas in Yunnan.The compound fungicide can improve the quality of tobacco significantly.The results are as follows:Rhizosphere microorganism has an important influence on plant growth and quality.In this study,tobacco and tobacco rhizosphere soil samples were collected from 10 tobacco areas in Yunnan Province,and the interaction among rhizosphere microorganism,soil physio-chemical properties and tobacco leaf properties was investigated.Redundancy analysis(RDA)showed that most of the soil physio-chemical properties had a significant impact on the rhizosphere microbial community.Correlation analysis and RDA analysis showed that available potassium(AK)and Acidobacter-gp3 were positively correlated to tobacco leaf traits,while topography,altitude and rotation mode had more significant effects on rhizosphere microbial community.Analysis of variance distribution showed that rhizosphere microorganism had a great influence on tobacco quality.In general,the diversity of tobacco rhizosphere microorganism is quite different,and there are complex interactions among microbial diversity,soil physio-chemical characteristics and tobacco characters.The results have certain reference value to promote the growth and improve the quality of tobacco.In this study,127 samples of aged flue-cured tobacco leaves from Yunnan,Zimbabwe,Zimbabwe,Fujian,Guizhou,Zhengyu,Shiyan in Hubei and Chenzhou in Hunan were collected,and 23 samples of fresh tobacco leaves and rhizosphere soil from main tobacco planting areas in Yunnan were collected The results are as follows: 1035 strains of microorganisms were isolated from 127 aged tobacco samples,including 1035 strains of bacteria,5 strains of yeast and 95 strains of molds.284 strains of bacteria,65 strains of fungi and 102 strains of Actinomycetes were isolated from 23 fresh tobacco leaves and tobacco rhizosphere soil samples.Through molecular biological identification,156 strains of Bacillus were isolated from the aged tobacco samples,which were divided into 19 species.B.subtilis was found in most of the samples.284 strains of bacteria isolated from fresh tobacco leaves and soil were divided into 27 genera and 96 species.Among them,Bacillus contains 34 different species,which is the dominant population.There are a large number of microorganisms on the leaf surface of tobacco.These microorganisms can transform many bio-macromolecular into small molecular compounds within tobacco,such as alcohols,aldehydes,esters,ketones and organic acids,so that it can improve the quality of tobacco.In this study,the ability of producing hydrolase of the isolated bacteria was tested.24 strains with better ability of producing hydrolase were screened out from 1035 strains of old tobacco leaves,20 strains with better ability of producing hydrolase were screened out from 284 strains of fresh tobacco leaves and tobacco rhizosphere soil.A total of 44 strains of bacteria were fermented by single strain tobacco.The results showed that strains 16-2,YN36-5,YN21-1.The comprehensive effect of HJ39-9 and HJ8-8 is the best,which has great influence on the quality of tobacco fermentation.Strains 16-2,YN36-5,YN21-1,HJ39-9 and HJ8-8 According to the proportion of 1:1,three sets of compatible fungicides with good effect were obtained by sensory evaluation,which were composite strain T1(16-2;YN21-1),T6(YN36-5;YN21-1)and T7(HJ8-8;YN21-1).At the same time,the physical and chemical properties of tobacco after fermentation also had obvious changes.In order to investigated the selected 5 excellent strains,this study carried out Gram staining,physiological and biochemical characteristics test of 5 strains and based on 16 s r DNA.The results showed that strain 16-2,YN36-5 and HJ8-8 were purple,which indicated that they were gram-positive,strain YN21-1 and HJ9-9 were red,which indicated that they were gram-negative.Through the sequence similarity and phylogenetic relationship of 16 s r DNA,we can preliminarily determine that 16-2 is Bacillus cereus,YN36-5 is Bacillus thuringiensis,HJ8-8 is endophytic,YN21-1 is Pseudomonas fulva,HJ39-9 is Pseudomonas stutzeri. |
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