| Fermented bamboo shoots(FBS),a traditional fermentation food,is popular in southern China of its rich nutrition and unique flavor.Previous studies of FBS mainly focused on nutrient contents,flavor substance and process optimization and so on.However,little exploration of microbial composition,dominant strains and their genes expressed functions.Our study was conducted in typical households of six representative traditional regions of China(Guilin,Liuzhou,Laibin,Baise,Nanning and Guigang),which collected the fermentation liquid from the middle of a FBS jar by investigating the best local FBS,total 18 samples with 3 replications,In this study,we attempted to investigate microbial diversity,abundance and gene function by the Illumina Hi Seq metagenomic sequencing.The metabolism of amino acid,organic acid and nitrite in its microorganism was analyzed emphatically.Mainly to reveal overview of Microorganisms and investigate the relationship between microorganisms and nutrients and flavor substances in FBS.The main results are as follows:1.Microbial diversity of FBS.The metagenomic data of FBS(Dendrocalamus latiflorus)from 6 producing areas analysis show that total of 156 species of microbial were identified in 18 samples,belonging to 8 phyla,16 classes,30 orders,63 families and 92 genus,which is higher than 22 reported methods such as traditional culture and 16 S sequencing.Firmicute accounted for 86.10% and Lactobacillus accounted for 84.84%.L.fermentum?L.plantarum?L.amylolyticus?L.buchneri?L.brevis are dominant strains in FBS,which had probiotic function accounting for 65%,harmful bacteria(0.24%)and unknown function(30.26%).The results of the alpha diversity analysis revealed that those in Guigang had the highest microbial diversity(shannon index 1.65)and the largest number of microbial species detected(77 species);Liuzhou had the lowest microbial diversity(shannon index 0.73)and the number of microbial species detected(13 species).The results of principal component analysis showed that the microbial communities of fermented bamboo shoots from Guilin,Liuzhou and Laibin were similar,those from Baise and Nanning had similar microbial composition,while that of Guigang samples exhibited obviously difference from other 5 regions.2.Analysis of microbial gene of FBS.A total of 75681 genes of fermented shoot microbe were obtained by metagenomic method,and 54416 unigenes were predicted,which 53265 can be compared to known protein sequences.37747 unigene annotated in the egg NOG database and belonged to 22 functional categories of which the two classes associated withthe amino acid transport and carbohydrate metabolism were the highest.19051 unigenes were annotated by the KEGG database and belonged to 384 metabolic pathways of which72 pathway were involved in the metabolism.Additionally,annotates KEGG pathways of L.plantarum were the most meaning it was the metabolically active microorganism during the fermented shoot production process.6152 unigenes were annotated by the GO database and belonged to 58 biological categories.3.Analysis of nutrition and flavor metabolism of FBS.This study analyzed the metabolism pathways of acid(amino acid,lysine,etc),organic acids(lactic acid and acetic acid),nitrite and so on during the formation of quality nutrients and flavor substances in FBS.It was found that microbial has important biological coordination function in FBS.4.Analysis of FBS producing area microorganisms differential function genes.The result of functional gene annotation and pathway show that the differential genes were the most between Guilin and Liuzhou(38947).But the differential genes were least between Guilin and Nanning(2223).These differential genes can be classified into 38 functional categories and 133 KEGG pathways.The microbial metagenomic level reveals the possible mechanism of the quality and personality of FBS in different places... |
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