辣椒4-香豆酸辅酶A连接酶基因Ca4CL02克隆及表达分析OA

4-coumarate-CoA ligase(4CL)is a key rate-limiting enzyme in the plant phenylpropanoid metabolic pathway and plays a vital role in plant growth,development,and stress tolerance responses.Previous studies have identified eight homologous genes encoding 4CL in the pepper genome.In this study,the pepper Ca4CL02 gene was cloned,and its expression characteristics were analyzed to explore its potential functions in plant growth,development,and stress tolerance.Multiple approaches including gene cloning,bioinformatics analysis,RT-qPCR,and GUS transient transformation system were adopted to characterize the gene sequence,expression patterns,and low-temperature promoter activity.The results showed that the full-length sequence of Ca4CL02 is 1 647 bp,encoding 549 amino acids.This gene contains only one exon without introns.The predicted Ca4CL02 protein harbors a conserved AMP-binding domain,is localized to peroxisomes,and is a hydrophobic and unstable protein with a transmembrane domain.Tissue-specific expression analysis revealed that Ca4CL02 was constitutively expressed in all tested pepper tissues,with the highest expression level in stems and the lowest in young fruits.Low temperature,mannitol,and salicylic acid significantly induced Ca4CL02 expression in leaves or roots,whereas high temperature markedly inhibited its expression.Promoter sequence analysis demonstrated that the Ca4CL02 promoter contains multiple cis-acting elements associated with low-temperature response,light response,and hormone response.Transient transformation assays indicated that under 4℃low-temperature stress,the GUS signal driven by the Ca4CL02 promoter increased with prolonged treatment time and peaked at 24 h.In conclusion,the Ca4CL02 promoter is significantly induced by low temperature.The Ca4CL02 gene may participate in the regulation of pepper growth and development as well as multiple abiotic stress responses,serving as an important candidate gene for stress-tolerant breeding in pepper.