title: The effects of threshing and redrying on bacterial communities that inhabit the surface of tobacco leaves.
abstract: Before being subjected to the aging process, raw tobacco leaves (TLs) must be threshed and redried. We propose that threshing and redrying affect the bacterial communities that inhabit the TL surface, thereby influencing the aging process. However, these effects remain unclear. In this study, Illumina sequencing was applied to analyze the bacterial communities on both raw and redried TLs. Shannon's diversity value decreased from 3.38 to 2.52 after the threshing and redrying processes, indicating a large reduction in TL bacterial diversity. The bacterial communities also largely differed between raw TLs and redried TLs. On unaged raw TLs, Proteobacteria was the most dominant phylum (56.15%), followed by Firmicutes (38.99%). In contrast, on unaged redried TLs, Firmicutes (76.49%) was the most dominant phylum, followed by Proteobacteria (21.30%). Thus, the dominant genus Proteobacteria, which includes Sphingomonas, Stenotrophomonas, and Pantoea, decreased after the threshing and redrying processes, while the dominant genus Firmicutes, which includes Bacillus and Lactococcus, increased. Changes in the bacterial communities between raw and redried TLs were also noted after 1 year of aging. The relative abundance of dominant Proteobacteria taxa on raw TLs decreased from 56.15 to 16.92%, while the relative abundance of Firmicutes taxa increased from 38.99 to 79.10%. However, small changes were observed on redried TLs after 1 year of aging, with a slight decrease in Proteobacteria (21.30 to 17.64%) and a small increase in Firmicutes (76.49 to 79.10%). Based on these results, Firmicutes taxa may have a higher tolerance for extreme environments (such as high temperature or low moisture) than Proteobacteria bacteria. This study is the first report to examine the effects of threshing and redrying on bacterial communities that inhabit TLs.
authors.affiliation: School of Food and Biological Engineering, Henan Provincial Collaborative Innovation Center for Food Production and Safety, Zhengzhou University of Light Industry, Dongfeng Road, 5#, Zhengzhou, Henan Province, 450002, China.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Ye
authors.affiliation: School of Food and Biological Engineering, Henan Provincial Collaborative Innovation Center for Food Production and Safety, Zhengzhou University of Light Industry, Dongfeng Road, 5#, Zhengzhou, Henan Province, 450002, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Yan
authors.affiliation: Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou, 450000, China.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou, 450000, China.
authors.forename: Zongcan
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou, 450000, China.
authors.forename: Xiangzhen
authors.initials: X
authors.lastname: Liu
authors.affiliation: Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou, 450000, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou, 450000, China.
authors.forename: Genfa
authors.initials: G
authors.lastname: Wang
authors.affiliation: Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou, 450000, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Hao
authors.affiliation: School of Food and Biological Engineering, Henan Provincial Collaborative Innovation Center for Food Production and Safety, Zhengzhou University of Light Industry, Dongfeng Road, 5#, Zhengzhou, Henan Province, 450002, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Ma
authors.affiliation: Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou, 450000, China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Ma
authors.affiliation: School of Food and Biological Engineering, Henan Provincial Collaborative Innovation Center for Food Production and Safety, Zhengzhou University of Light Industry, Dongfeng Road, 5#, Zhengzhou, Henan Province, 450002, China. maoduobin@zzuli.edu.cn.
authors.forename: Duobin
authors.initials: D
authors.lastname: Mao
authors.affiliation: School of Food and Biological Engineering, Henan Provincial Collaborative Innovation Center for Food Production and Safety, Zhengzhou University of Light Industry, Dongfeng Road, 5#, Zhengzhou, Henan Province, 450002, China. yangxp0000@163.com.
authors.forename: Xuepeng
authors.initials: X
authors.lastname: Yang
mesh_terms: D000068536:Bacillota / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D014644:Genetic Variation; D059014:High-Throughput Nucleotide Sequencing; D059013:Microbial Consortia / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D018515:Plant Leaves / Q000382:microbiology*; D020560:Proteobacteria / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D012336:RNA, Ribosomal, 16S; D014026:Nicotiana / Q000382:microbiology*
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Bacterial diversity; Illumina sequence; Raw tobacco leaves; Redried tobacco leaves