| Nicotiana tabacum is an important cash crop in China,but there are many problems in the upper tobacco leaf.To ensure that the demand for raw materials in the cigarette industry is met,this study selected Saccharomyces cerevisiae as the fermentation strain for improving upper tobacco leaves quality,which has advantages such as strong fermentation capacity,rapid proliferation,and high resistance.In this study,the upper tobacco leaves of GZ36(GZ),K326(K),and Yunyan 87(Y)were used as research materials,to screen the optimal inoculation conditions of Saccharomyces cerevisiae of tobacco leaves,and to explore the influence of Saccharomyces cerevisiae on the microbial community of the upper tobacco leaf by High-throughput Sequencing Technology,to clarify the correlation between the microbial community and the quality of tobacco leaves,to provide a scientific basis for the research on the microbial mechanism of tobacco leaves,and to provide a reference for improving the overall quality and economic benefits of tobacco leaves.The main research results are as follows:Orthogonal experiments were used to explore the effects of Saccharomyces cerevisiae on tobacco leaves under different concentrations,inoculation amounts,and treatment times.The primary and secondary influencing factors were inoculation concentration>treatment time>inoculation amount.The strength of each influencing factor level was 10~6CFU/mL>10~8CFU/mL>10~7CFU/mL,10 mL>30 mL>20 mL,2 h>4 h>6 h.Based on the optimal level of each factor,the optimal inoculation conditions for Saccharomyces cerevisiae to inoculate tobacco leaves were 10~6CFU/mL,10 mL,and 2 h.There are differences in the effects of Saccharomyces cerevisiae on fungi and bacteria in tobacco leaves.Compared with the control tobacco leaf(CK),the diversity of tobacco leaf fungi treated with Saccharomyces cerevisiae(Z2)increased and richness decreased,while the richness and diversity of bacterial community increased.The dominant genera in GZCK tobacco leaves of variety GZ36 are Sampaiozyma and Terribacillus;the dominant genera in GZZ2 tobacco leaves are Saccharomyces,Escherichia Shigella,and Terribacilluses.The dominant genera in KCK tobacco leaves of variety K326 are Sampaiozyma and Bacillus;the dominant genera in KZ2tobacco are Saccharomyces,Bacillus,and Thioalkalibacter.The dominant genera in YCK tobacco leaves of Yunyan 87 are Alternaria,Pantoea,and Sphingomonas;the dominant genera in YZ2tobacco are Saccharomyces and Bacillus.There are differences between treatment tobacco leaf microbial community and CK tobacco leaves,and the results show that Saccharomyces cerevisiae can affect the microbial community structure of tobacco leaves and occupy a dominant positionAfter being treated with Saccharomyces cerevisiae,improved sensory quality of tobacco leaves;GZ36 and Yunyan 87 tobacco leaf quality significantly improved,while K326 tobacco leaves did not significantly improve.Sensory quality was correlated with dominant species(Genus Level),and aroma quantity and aftertaste were the most significant factors correlated with microbial communities.After treatment with Saccharomyces cerevisiae,improved chemical coordination of tobacco leaves;the chemical harmony of GZ36 and Yunyan 87 tobacco leaves was significantly improved,while the improvement of K326 tobacco leaves was not significant.Chemical harmony is associated with dominant species(Genus level),with nicotine and reducing sugars being the most significant factors associated with microbial communities. |
