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BACKGROUND: The microbial community plays a crucial role in Chinese strong‐flavor baijiu (SFB) fermentation. However, the seasonal dynamics of the microbial community in the SFB fermentation system and its contribution to the unique flavor of SFB have not been fully elucidated. In this study, we investigated the seasonal dynamics of the microbial community through 16S rRNA and ITS gene sequencing. RESULTS: The results revealed significant temporal dynamics of microbial communities and environmental variables throughout the four seasons. The influence of seasons on fungal communities was found to be more significant than on bacterial communities. The diversity of bacteria was higher during the winter and summer, whereas fungal diversity was more prominent in summer and autumn. Stochastic processes maintained their dominance in microbial assembly throughout all four seasons but the significance of heterogeneous selection increased during summer for both bacteria and fungi, whereas homogeneous selection became more pronounced during winter for fungi. The pH and environmental temperature were important drivers of microbial community assembly across different seasons, primarily impacting the core genera responsible for the production of major volatile flavor compounds (VFCs), especially ethyl caproate. CONCLUSION: These findings provide new insights into the impact of seasons on microbial communities and hold promise for improving the quality‐control measures for SFB brewed in different seasons. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Eucalyptus is a highly diverse genus of the Myrtaceae family and widely planted in the world for timber and pulp production. Tissue culture induced callus has become a common tool for Eucalyptus breeding, however, our knowledge about the genes related to the callus maturation and shoot regeneration is still poor. Results: We set up an experiment to monitor the callus induction and callus development of two Eucalyptus species - E. camaldulensis (high embryogenic potential) and E. grandis x urophylla (low embryogenic potential). Then, we performed transcriptome sequencing for primary callus, mature callus, shoot regeneration stage callus and senescence callus. We identified 707 upregulated and 694 downregulated genes during the maturation process of the two Eucalyptus species and most of them were involved in the signaling pathways like plant hormone and MAPK. Next, we identified 135 and 142 genes that might play important roles during the callus development of E. camaldulensis and E. grandis x urophylla, respectively. Further, we found 15 DEGs shared by these two Eucalyptus species during the callus development, including Eucgr.D00640 (stem-specific protein TSJT1), Eucgr.B00171 (BTB/POZ and TAZ domain-containing protein 1), Eucgr.C00948 (zinc finger CCCH domain-containing protein 20), Eucgr.K01667 (stomatal closure-related actinbinding protein 3), Eucgr.C00663 (glutaredoxin-C10) and Eucgr.C00419 (UPF0481 protein At3g47200). Interestingly, the expression patterns of these genes displayed "N" shape in the samples. Further, we found 51 genes that were dysregulated during the callus development of E. camaldulensis but without changes in E. grandis x urophylla, such as Eucgr.B02127 (GRF1-interacting factor 1), Eucgr.C00947 (transcription factor MYB36), Eucgr.B02752 (laccase-7), Eucgr.B03985 (transcription factor MYB108), Eucgr.D00536 (GDSL esterase/lipase At5g45920) and Eucgr.B02347 (scarecrow-like protein 34). These 51 genes might be associated with the high propagation ability of Eucalyptus and 22 might be induced after the dedifferentiation. Last, we performed WGCNA to identify the co-expressed genes during the callus development of Eucalyptus and qRT-PCR experiment to validate the gene expression patterns. Conclusions: This is the first time to globally study the gene profiles during the callus development of Eucalyptus. The results will improve our understanding of gene regulation and molecular mechanisms in the callus maturation and shoot regeneration. [ABSTRACT FROM AUTHOR]

In order to provide genetic parameters of growth and Quambalaria shoot blight (QSB) resistance in Corymbia citriodora subsp. variegata (CCV), two trials of 91 open-pollinated families from 10 provenances were established in southern China. Effects of variance components of provenance and/or family within provenance were significant (p ≤ 0.05, 0.01, or 0.001) for most growth traits (tree height at seven, 12, 21, 29, and 46 months as well as breast-high diameter and single-tree volume at 21, 29, and 46 months) and QSB resistance (at 7 months) at each trial and across trials. Narrow-sense heritability estimates ranged from 0.04 to 0.46 in growth and 0.01 to 0.27 in QSB resistance, indicating generally low to moderate levels of additive genetic control of the traits studied. Proportions of provenance to phenotypic variance were also generally low, being 0.02–0.22 for growth and 0.01–0.23 for QSB resistance. Genetic correlations were significant and positive between growth traits and also between growth and QSB resistance, meaning that better growth at older ages could be expected from early-stage selection in growth and/or QSB resistance in CCV. Except for 29-month-old breast-high diameter, type-B correlations between trials were significant for all the traits, which suggested strong genotype by environment effects. [ABSTRACT FROM AUTHOR]

The popular distilled Chinese strong-flavour liquor (CSFL) is produced by solid fermentation in the ground pit. Microbes inhabiting in the pit mud (PM) on the walls of the fermentation pit are responsible for the production of caproic acid (CA) that determines the quality of CSFL to a large degree. However, little is known about the active microbial populations and metabolic potential of the PM microbiome. Here, we investigated the overall metabolic features of the PM microbiome and its active microbial components by combining metagenomics and MiSeq-sequencing analyses of the 16S rRNA genes from DNA and RNA (cDNA). Results showed that prokaryotes were predominant populations in the PM microbiome, accounting for 95.3% of total metagenomic reads, while eukaryotic abundance was only 1.8%. The dominant prokaryotic phyla were Firmicutes, Euryarchaeota, Bacteroidetes, Actinobacteria and Proteobacteria, accounting for 48.0%, 19.0%, 13.5%, 2.5% and 2.1% of total metagenomic reads respectively. Most genes encoding putative metabolic pathways responsible for the putative CA production via chain elongation pathway were detected. This indicated that the PM microbiome owned functional potential for synthesizing CA from ethanol or lactate. Some key genes encoding enzymes involved in hydrogenotrophic and acetoclastic methanogenesis pathways were detected in the PM metagenome, suggesting the possible occurrence of interspecies hydrogen transfer between CA-producing bacteria and methanogens. The 16S rDNA and 16S rRNA profiles showed that the Clostridial cluster IV, Lactobacillus, Caloramator, Clostridium, Sedimentibacter, Bacteroides and Porphyromonas were active populations in situ, in which Clostridial cluster IV and Clostridium were likely involved in the CA production. This study improved our understandings on the active populations and metabolic pathways of the PM microbiome involved in the CA synthesis in the CSFL fermentation. [ABSTRACT FROM AUTHOR]

Fresh raw liquors distilled from Zaopei fermented in new, trend to-be aged and aged pit mud, labelled as N1 and N2, T1 and T2, and A1 and A2, respectively, were analysed by sensory evaluation, two-dimensional gas chromatography/time-of-flight mass spectrometry with combined principal component analysis, gas chromatography-flame ionization detection, liquid chromatography-mass spectrometry with combined hierarchical cluster analysis, and partial least square-discrimination analysis. Results showed that samples had the same grouping situations by each method: the N-group containing N1 and N2; the T-group containing T1 and T2; and the A-group containing A1 and A2. The specific markers for the N-group liquors were 2-butanol and butanoic acid, and those for the A-group were 1-hexanol, ethyl pentanoate and 2-pentanone. The threshold contents of 1-hexanol, ethyl pentanoate, and 2-pentanone for the A-group liquors were 1207.95 ± 252.59, 469.89 ± 73.08 and 1105.12 ± 141.91 mg L−1, while those of 2-butanol and butanoic acid for the N-group liquors were 215.66 ± 179.50 and 430.65 ± 60.47 mg L−1, respectively. The results from modern chromatographic techniques and chemometric analyses verify the correctness of the traditional sensory evaluation used in controlling the quality of Chinese liquor, contribute to further studies related to the aroma and flavour of Chinese Luzhou-flavour of fresh raw liquors and may provide significantly helpful thresholds in distinguishing Chinese Luzhou-flavour fresh raw liquors distilled from Zaopei fermented in new, trend to-be aged and aged pit muds. Copyright © 2017 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]