Functional characterization of tomato genes encoding B-box family proteins and their interactors

Abstract

The B-Box (BBX) proteins are zinc-finger transcription factors (TF) characterized by the presence of at least one B-Box domain. In Arabidopsis thaliana, they were classified in five structural groups and functionally described as important regulators of photomorphogenesis, flowering, shade avoidance, biotic and abiotic responses, and, even, hormones signaling pathways. In tomato, Solanum lycopersicum, 31 BBX encoding genes were identified and classified into six structural groups. There are only few SlBBXs functionally characterized, which participate in the regulation of important processes, such as photomorphogenesis, auxin and jasmonic acid (JA) metabolism, cartenogenesis, anthocyanins synthesis, heat and cold tolerance, and flowering. So far, BBX proteins mode of action has been associated to that performed by classical TFs, physically interacting with other regulatory proteins and/or DNA motifs in the promoters of the target genes. However, there is no information whether BBX genes are regulated or regulate target genes by epigenetic mechanisms. In this context, this project aims to obtain and functional characterize tomato mutant knockout lineages for SlBBX17, SlBBX24, and their interactors SlHDA8 (histone deacetylase) and SlLHP1a (histone H3 Lys 27 trimethylase), using the CRISPR-Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats) system, to unravel their function in vegetative and reproductive development and, therefore, their putative role in nutritional quality. (AU)