Characterization and Expression Profiling of AREB gene(s) in Solanum lycopersicum Genotype(s) under Abiotic stress(s)

Abstract

AREB (ABA-Responsive Element Binding) gene subfamily performs a vital role in transcriptional regulation and increases the tolerance of the plants against abiotic stresses. In the present research, genome-wide identification, characterization, and expression profilings of the AREB gene subfamily has been performed in tomato. By the genome-wide searching of tomato genome assembly ITAG4.0, 8 SlAREB genes have been screened out with the confirmation of bZIP domain. Phylogenetic analysis showed that they fall into two groups (group A and B). Moreover, gene structure analysis and motif composition further give the validation of the formation of two phylogenetic groups as members of the same groups have same motif composition and intron exons organization. All SlAREB genes were randomly localized on 5 out of 12 tomato chromosomes. Gene duplication analysis revealed that SlAREB genes go through segmental gene duplication. Syntenic maps depicted that 7 and 12 SlAREB orthologous gene pairs were identified in Arabidopsis thaliana and Solanum tuberosum, respectively. Gene ontology annotation showed they have different biological and molecular functions. Moreover, sub-cellular localization studies revealed that these genes are localized in the nucleus. Five groups of 534 cis- regulatory elements have been found by promotor analysis. Further, two SlAREB proteins from each group have been selected for homology modelling and the models’ quality has been validated. Functional and structural diversities of SlAREB proteins were further proved by finding the protein binding pockets and disorder region within proteins. Protein interactive association studies showed that SlAREB proteins form association with other proteins. Differential gene expression analysis for AREB5/ABI5 (group B) shows significant expression in leaves with the relative fold change of 41.011 as compared to roots having 2.026-fold change on 7th day stage while on 14th day it also shows more expression in leaves with 31.895 relative fold change as compared to roots having 21.565-folds. On the other hand, SlAREB6 shows significant expression in leaves with the relative fold change of 15.011 as compared to roots having 4.304-fold change on 7th day stage while on 14th day it shows more expression in roots with 6. 893 folds as compared to leaves having 3.011- folds. Overall, the results provide the knowledge about the identification, extensive molecular characterization, and expression analysis of AREB subfamily genes in tomato under drought stress which can be used in future for the formation of drought stress-tolerant tomato hybrids.