Microbial communities and carotenoid metabolism associated with aroma-related volatile profiles in fermented cigar tobacco leaves

Cigar tobacco leaves (CTLs) are high-value industrial raw materials whose aroma quality is shaped by post-harvest fermentation and aging. This study investigated the associations among microbial communities, residual plastid pigment pools, carotenoid metabolism, and volatile organic compounds (VOCs) in commercially fermented CTLs. High-throughput sequencing revealed significant differences in bacterial and fungal community structures among samples. Plastid pigment analysis showed marked variation, particularly in β-carotene and lutein, indicating substantial heterogeneity in residual precursor pools. GC×GC-TOFMS detected 46 common VOCs, and PLS-DA identified 15 key differential VOCs, among which carotenoid-derived compounds such as 4-hydroxy-β-ionone, dihydroactinidiolide, and geranylacetone were important markers of aroma differentiation. Correlation network analysis showed that Staphylococcus was positively associated with multiple carotenoid-derived VOCs. PICRUSt2-based prediction further suggested sample-specific differences in inferred carotenoid-related metabolic potential, with YY5 showing stronger precursor synthesis potential and YY2 showing greater downstream structural modification. Overall, the study links microbial variation, plastid pigment metabolism, and aroma-related volatile differentiation in CTLs and provides candidate indicators for fermentation monitoring and quality control. • Microbiome and volatilome were profiled in seven fermented cigar leaves. • Fifteen differential VOCs distinguished CTLs across origins and aging durations. • Carotenoid-derived norisoprenoids were key markers of aroma variation. • Staphylococcus was positively linked to multiple carotenoid-derived VOCs. • PICRUSt2 suggested sample-specific carotenoid-related metabolic potential.