Genome-wide identification, genomic organization, and expression profiling of the CONSTANS-like (COL) gene family in petunia under multiple stresses

Background: CONSTANS-like (CO-like, COL) is a putative zinc-finger transcription factor family that plays a key role in the control of flowering time in photoperiod-sensitive plants. Besides, the COL family protein is also involved in plant development, responses to stresses. However, information on plant development and stress response related function has not been previously performed in any solanaceous crop. In this study, a genome-wide analysis of COL gene family was conducted in Petunia hybrida cv. Mirage Rose to elucidate their roles in organ development and stress response. Results: A total of 15 COL genes were identified in petunia. Based on their amino acid sequence identity and domain composition they were phylogenetically classified into three groups those are conserved among the flowering plants. Similar gene structure and motif distribution were observed in the same group. Subcellular localization assays demonstrated that all PaCOL proteins were localized in nucleus. Furthermore, differential expression patterns of PaCOL genes were observed in various tissues. The expression patterns of PaCOL genes were observed under various abiotic and phytohormone treatment to explore their relatedness in different stresses. Moreover, several stress and light-responsive cis- elements were detected for different PaCOL genes. Conclusion: The COL genes of petunia genome, those were clustered into three distinct groups, are conserved among flowering plants, were expressed in different tissues and induced under multiple abiotic stress treatments indicating their involvement in plant growth and development and stress response mechanism. This work laid the significant foundation for functional characterization of PaCOL gene family to uncover their biological roles in plant growth, development and in stress response.