Regulates Flowering Time under Long-Day Conditions in .

Flowering in plants is pivotal for initiating and advancing reproductive processes, impacting regional adaptation and crop yield. Despite numerous cloned and identified flowering time genes, research in cotton remains sparse. This study identified as a key determinant of the flowering time in cotton, demonstrating that its heterologous expression in accelerated flowering under LD conditions compared to WT. Transgenic plants exhibited upregulated expression of the flowering inducers , , , and , alongside downregulated expression of the repressors , , and , correlating with the earlier flowering phenotype. showed a constitutive expression pattern, with elevated levels in the leaves, petals, and flower buds, and was notably higher in early-maturing cotton varieties. Subcellular localization assays confirmed GhSWEET42's presence on the cell membrane. Transcriptome analysis between WT and -overexpressing plants revealed 2393 differentially expressed genes (DEGs), spanning 221 biological processes, 93 molecular functions, and 37 cellular components according to Gene Ontology (GO) enrichment analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis categorized the DEGs into metabolism and environmental information processing. These findings enhance the understanding of 's function and provide a foundation for elucidating the molecular mechanisms governing flowering time regulation in cotton.