The FBXL Gene Family in Tobacco (Nicotiana tabacum L.): Identification and Expression Response to TMV and Abiotic Stresses

F-box-LRR (FBXL) proteins are crucial components of the SCF ubiquitin ligase complex, regulating diverse processes such as development and stress responses in plants. However, the FBXL family in tobacco (<i>Nicotiana tabacum</i> L.) remains poorly characterized. This study performed the first genome-wide analysis of the <i>FBXL</i> gene family in tobacco and identified 47 <i>NtaFBXL</i> genes. Phylogenetic analysis classified them into five clades, among which Clade III exhibited notable expansion. Promoter analysis revealed abundant stress- and hormone-related cis-elements. Expression profiling demonstrated tissue-specific patterns and strong responses to drought, ABA, IAA, and TMV infection. Importantly, six genes exhibited a significant negative correlation with TMV accumulation, suggesting their potential roles in antiviral defense. Moreover, both drought and TMV stress triggered a disturbance of redox homeostasis, a dynamic process that was closely associated with the expression of specific <i>NtaFBXL</i> genes, characterized by upregulated antioxidant enzymes (SOD, POD, CAT) and accumulated oxidative markers (H₂O₂, MDA). Collectively, this study provided a foundational resource for understanding the function of <i>NtaFBXLs</i> and identified key candidate genes for the genetic improvement of stress resistance in tobacco.