Abstract
Light controls several aspects of plant development through a complex signalling cascade. Several B-box domain containing proteins (BBX) were identified as regulators of Arabidopsis thaliana seedling photomorphogenesis. However, the knowledge about the role of this protein family in other physiological processes and species remains scarce. To fill this gap, here BBX protein encoding genes in tomato genome were characterised. The robust phylogeny obtained revealed how the domain diversity in this protein family evolved in Viridiplantae and allowed the precise identification of 31 tomato SlBBX proteins. The mRNA profiling in different organs revealed that SlBBX genes are regulated by light and their transcripts accumulation is directly affected by the chloroplast maturation status in both vegetative and fruit tissues. As tomato fruits develops, three SlBBXs were found to be upregulated in the early stages, controlled by the proper chloroplast differentiation and by the PHYTOCHROME (PHY)-dependent light perception. Upon ripening, other three SlBBXs were transcriptionally induced by RIPENING INHIBITOR master transcriptional factor, as well as by PHY-mediated signalling and proper plastid biogenesis. Altogether, the results obtained revealed a conserved role of SlBBX gene family in the light signalling cascade and identified putative members affecting tomato fruit development and ripening.
Highlights
Zinc finger transcription factors (TFs) comprise one of the most important families of transcriptional regulators in plants and play a central role in plant growth and development regulation, as well as in biotic and abiotic stress responses[1,2]
It was demonstrated that PIF3 and PIF1 transcription factors signalling cascade regulates AtBBX23 transcription, whose product physically interacts with HYPOCOTYL 5 (HY5) inducing photomorphogenesis in A. thaliana seedlings[12]
The B-box domain containing proteins (BBX) TF family has been extensively studied in A. thaliana, whose proteins were classified into five groups to the domain structure[3,5]
Summary
Zinc finger transcription factors (TFs) comprise one of the most important families of transcriptional regulators in plants and play a central role in plant growth and development regulation, as well as in biotic and abiotic stress responses[1,2] Among these TFs, B-box domain containing proteins (BBX) belong to a subclass characterised by the presence of one or two zinc finger B-box domains, which are predicted to be involved in protein–protein interactions[3]. The above-described links between BBXs and light signalling have been almost exclusively explored in seedling photomorphogenesis, and their role in other light-controlled physiological processes, such as plastid development and maintenance, plant architecture and fruit development, which are important determinants of crop yield and nutritional q uality[27], remains elusive. It was addressed whether the mRNA accumulation of these six genes is regulated by PHYTOCHROME (PHY)-mediated light perception and/or plastid development and differentiation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
