楸树NAC基因家族鉴定及低温胁迫响应关键基因筛选OA

NAC(NAM,ATAF,and CUC)transcription factors are plant-specific transcriptional regulators that play crucial roles in plant growth,development,and responses to abiotic stresses.To systematically characterize the molecular evolutionary features of the NAC gene family in Catalpa bungei and elucidate its regulatory mechanisms under cold stress,NAC gene family members were comprehensively identified based on the whole-genome sequence of C.bungei.Comprehensive analyses were performed,including physicochemical properties,phylogenetic topology,gene structure conservation,cis-acting elements in promoter regions,cold-responsive expression patterns,and weighted gene co-expression network analysis(WGCNA).The results demonstrated that a total of 65 CbuNAC genes were identified in the C.bungei genome and classified into four highly conserved subfamilies based on phylogenetic analysis.Chromosomal mapping revealed that these genes were unevenly distributed across 16 chromosomes,displaying a distinct clustered distribution pattern.Gene structure and conserved motif analyses indicated that members within the same subfamily exhibited highly similar intron-exon organization and conserved motif composition,which not only supported the reliability of the phylogenetic classification but also implied potential functional redundancy and evolutionary divergence within subfamilies.Collinearity analysis indicated that segmental duplication,rather than tandem duplication,was the predominant driving force for the expansion and evolutionary divergence of the CbuNAC gene family.Time-series transcriptome analysis under cold stress revealed that CbuNAC15,CbuNAC30,and CbuNAC36 were significantly upregulated,exhibiting strong and temporally dynamic responses to low-temperature stress.Furthermore,WGCNA revealed that the three core genes not only coordinately regulated the classical ICE1-CBF cold-signaling pathway but were also closely associated with downstream genes involved in osmotic adjustment and hormone metabolism.In summary,this study systematically characterized the genomic features of the NAC gene family in C.bungei and identified three key candidate genes associated with cold-tolerance,thereby providing valuable theoretical insights and candidate targets for elucidating abiotic stress adaptation mechanisms in woody plants and advancing marker-assisted breeding.