Comparative transcriptomic analysis of leaf greenness retention mechanisms in cigar tobacco (Nicotiana tabacum L.) during air-curing

Tobacco leaf curing is a critical postharvest process that determines the quality, aroma, and commercial value of the final product. During air-curing, persistent leaf greenness, known as the stay-green phenotype, significantly compromises color quality and reduces the commercial value of cigar tobacco. This project utilizes comparative transcriptomics to investigate the molecular mechanisms underlying leaf greenness retention in Nicotiana tabacum L. By comparing gene expression profiles between green-retained leaves and normal yellow leaves, the study identifies differentially expressed genes associated with leaf senescence, chlorophyll metabolism, and phytohormone signaling. The results demonstrate that the stay-green phenotype results from suppressed senescence signals and synchronized transcriptional reprogramming of pigment pathways. These findings provide insights for optimizing tobacco curing processes and enhancing product value.