Genes coding for B-box proteins are widespread in all eukaryotic genomes analyzed so far. In Arabidopsis and tomato, B-box Zn finger proteins contain one or two B-box domains which represent a sequence motif for protein-protein interaction. Many members of this family also possess a CCT-domain, which is associated with a role in transcriptional regulation and nuclear transport. The diverse functions of B-box proteins in plant growth and development range from the involvement in seedling photomorphogenesis, shade avoidance, seed germination and photoperiodic regulation of flowering. In Arabidopsis, several B-box proteins have been well‐characterized. For instance, AtBBX30 and AtBBX31 MicroProteins were proved to actively participate in the flowering process mediating the recruitment of CONSTANS (CO), a positive regulator of flowering time in a repressor complex with TOPLESS (TPL) with downstream inhibition of FLOWERING LOCUS T (FT) expression. The aim of this study is to functionally characterize two B-box proteins of tomato, BBX16 and BBX17, highly homologous to AtBBX30 and AtBBX31 also in light of our recent observation that BBX16 interacts with TCMP 2, a tomato cystine-knot miniprotein which is involved in flower and fruit production. First, we have demonstrated that TCMP-2 physically interacts also with AtBBX31 and when overexpressed in Arabidopsis causes anticipated flowering as well as an increased level of FT. In parallel, we have overexpressed SlBBX16 and SlBBX17 in Arabidopsis to find out whether they might have a regulatory function in flowering similar to AtBBX30 andAtBBX31. The study of the expression patterns of SlBBX16 and SlBBX17 in different phases of flower and fruit development is ongoing in tomato by using Agrobacterium tumefaciens-mediated transient expression of reporter gene constructs.

Involvement of B-box MicroProteins in the reproductive development of tomato

Valentina Dusi;Federica Pennisi;Barbara Molesini;Tiziana Pandolfini
2021

Abstract

Genes coding for B-box proteins are widespread in all eukaryotic genomes analyzed so far. In Arabidopsis and tomato, B-box Zn finger proteins contain one or two B-box domains which represent a sequence motif for protein-protein interaction. Many members of this family also possess a CCT-domain, which is associated with a role in transcriptional regulation and nuclear transport. The diverse functions of B-box proteins in plant growth and development range from the involvement in seedling photomorphogenesis, shade avoidance, seed germination and photoperiodic regulation of flowering. In Arabidopsis, several B-box proteins have been well‐characterized. For instance, AtBBX30 and AtBBX31 MicroProteins were proved to actively participate in the flowering process mediating the recruitment of CONSTANS (CO), a positive regulator of flowering time in a repressor complex with TOPLESS (TPL) with downstream inhibition of FLOWERING LOCUS T (FT) expression. The aim of this study is to functionally characterize two B-box proteins of tomato, BBX16 and BBX17, highly homologous to AtBBX30 and AtBBX31 also in light of our recent observation that BBX16 interacts with TCMP 2, a tomato cystine-knot miniprotein which is involved in flower and fruit production. First, we have demonstrated that TCMP-2 physically interacts also with AtBBX31 and when overexpressed in Arabidopsis causes anticipated flowering as well as an increased level of FT. In parallel, we have overexpressed SlBBX16 and SlBBX17 in Arabidopsis to find out whether they might have a regulatory function in flowering similar to AtBBX30 andAtBBX31. The study of the expression patterns of SlBBX16 and SlBBX17 in different phases of flower and fruit development is ongoing in tomato by using Agrobacterium tumefaciens-mediated transient expression of reporter gene constructs.
B-box MicroProteins , reproductive development, tomato
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/1048081
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