Structural diversity and stress regulation of the plant immunity-associated CALMODULIN-BINDING PROTEIN 60 (CBP60) family of transcription factors in Solanum lycopersicum (tomato)

• Published in: Functional & integrative genomics 2023-09, Vol.23 (3), p.236-236, Article 236
• Main Authors: Shivnauth, Vanessa, Pretheepkumar, Sonya, Marchetta, Eric J. R., Rossi, Christina A. M., Amani, Keaun, Castroverde, Christian Danve M.
• Format: Article
• Language: English
• Subjects: Abiotic stress; Amino acid sequence; Animal Genetics and Genomics; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biochemistry; Bioinformatics; Biomedical and Life Sciences; Calcium - metabolism; Calcium signalling; Calcium-binding protein; Calmodulin; Calmodulin - genetics; Calmodulin - metabolism; Calmodulin-Binding Proteins - genetics; Calmodulin-Binding Proteins - metabolism; Calreticulin; Cell Biology; Deep learning; Gene expression; Gene Expression Regulation, Plant; Gene regulation; Genomes; Immune response; Kinases; Life Sciences; Microbial Genetics and Genomics; Original Article; Pathogens; Plant Diseases - genetics; Plant Genetics and Genomics; Plant immunity; Plant Immunity - genetics; Protein kinase; Proteins; Salicylic acid; Salicylic Acid - metabolism; Solanum lycopersicum; Solanum lycopersicum - genetics; Tomatoes; Transcription factors; Transcription Factors - genetics
• ISSN: 1438-793X; 1438-7948
• DOI: 10.1007/s10142-023-01172-3

Cellular signaling generates calcium (Ca 2+ ) ions, which are ubiquitous secondary messengers decoded by calcium-dependent protein kinases, calcineurins, calreticulin, calmodulins (CAMs), and CAM-binding proteins. Previous studies in the model plant Arabidopsis thaliana have shown the critical roles of the CAM-BINDING PROTEIN 60 (CBP60) protein family in plant growth, stress responses, and immunity. Certain CBP60 factors can regulate plant immune responses, like pattern-triggered immunity, effector-triggered immunity, and synthesis of major plant immune-activating metabolites salicylic acid (SA) and N -hydroxypipecolic acid (NHP). Although homologous CBP60 sequences have been identified in the plant kingdom, their function and regulation in most species remain unclear. In this paper, we specifically characterized 11 members of the CBP60 family in the agriculturally important crop tomato ( Solanum lycopersicum ). Protein sequence analyses revealed that three CBP60 homologs have the closest amino acid identity to Arabidopsis CBP60g and SARD1, master transcription factors involved in plant immunity. Strikingly, AlphaFold deep learning–assisted prediction of protein structures highlighted close structural similarity between these tomato and Arabidopsis CBP60 homologs. Conserved domain analyses revealed that they possess CAM-binding domains and DNA-binding domains, reflecting their potential involvement in linking Ca 2+ signaling and transcriptional regulation in tomato plants. In terms of their gene expression profiles under biotic ( Pseudomonas syringae pv. tomato DC3000 pathogen infection) and/or abiotic stress (warming temperatures), five tomato CBP60 genes were pathogen-responsive and temperature-sensitive, reminiscent of Arabidopsis CBP60g and SARD1 . Overall, we present a genome-wide identification of the CBP60 gene/protein family in tomato plants, and we provide evidence on their regulation and potential function as Ca 2+ -sensing transcriptional regulators.