Genome-Wide Identification, Cloning and Expression Profile of RanBP2-Type Zinc Finger Protein Genes in Tomato

The RanBP2-type zinc finger (RBZ) protein genes, which are well-characterized in animals, are involved in the regulation of mRNA processing. Although they are diversely distributed in plants, their functions still remain largely unknown. In this study, we performed a comprehensive bioinformatic analysis of 22 RBZ genes in tomato. The gene structure analysis revealed that the SlRBZ genes have 2 to 17 exons. SlRBZ proteins contain typical conserved domains, including Motif 1 or Motif 2, or a combination of Motif 9 and Motif 4. Two paralogous pairs were identified in the tomato. Segmental duplication possibly contributed to the expansion of the SlRBZ genes in tomato. Interestingly, the SlRBZ15 gene generated four products, yielded by alternative splicing. A cis-regulatory element analysis revealed that SlRBZ genes might be involved in the complex regulatory networks during plant growth and development. The expression profiles of the SlRBZ genes were analyzed in different tissues using eight phytohormones and four abiotic stress treatments based on RNA sequencing data and qRT-PCR verification. The results showed that each gene responded differently to more than one phytohormone or abiotic stress type. This research provides a foundation for future functional research on SlRBZ genes in tomato.