Biology subjects

Rodrigues Bento, S.

Publications and source records attributed to Rodrigues Bento, S..

3 recordsLinked to original sources

bioRxiv2026

The FUL-SHP-AP2 module regulates fruit development in petunia

Fruit development is a typical angiosperm feature that greatly facilitates seed dispersal. Despite extensive studies on the gene regulatory network underlying pod shattering in the dry Arabidopsis fruit and the ripening process in the fleshy tomato fruit, it is yet unclear if a conserved regulatory network acts in early fruit development. Here, we investigated the roles of Petunia x hybrida (petunia) FRUITFULL (FUL), SHATTERPROOF (SHP) and APETALA 2 (AP2) homologs, three types of transcription factors repeatedly associated with fruit development and/or ripening. Petunia is closely related to tomato but produces dry dehiscent fruits like Arabidopsis. Our functional analysis revealed that the three petunia FUL-like genes, PETUNIA FLOWERING GENE (PFG), FLORAL BINDING PROTEIN 26 (FBP26) and FBP29, redundantly regulate endocarp development. They promote the formation of regularly shaped inner endocarp cells, probably via auxin/brassinosteroid signalling and cell wall modification. Furthermore, we discovered that the SHP-like gene FLORAL BINDING PROTEIN 6 (FBP6) has an opposite role, promoting more mesocarp-shaped endocarp cells, indicating that the FUL-like and SHP-like genes act antagonistically in early pericarp development. Finally, we show that the AP2-like genes REPRESSOR OF B-FUNCTION 1 (ROB1), ROB2 and ROB3 are crucial factors in petunia fruit development. rob1 rob2 rob3 mutants completely fail to dehisce and show major defects in pericarp patterning. The ROB transcription factors repress the activity of the FUL-like genes, and have, together with FBP6, an opposite effect on auxin and brassinosteroid signalling genes. Our study suggests that a module consisting of antagonistically acting TFs, including co-orthologs of AP2, FUL and SHP, regulates early pericarp patterning, at least partially via auxin and brassinosteroids.

plant biology↗

bioRxiv2025

Interplay between petal identity and cell layer identity in petunia flowers

In flowering plants, floral organ identity is specified by the combinatorial action of homeotic genes. While the role of these genes in the early specification of organ identity is well established, their late function throughout floral organ development and in specific cell types is much less characterized. In particular, since plant organs are structured in clonally-independent cell layers, whether and how homeotic identity interacts with cell layer identity is unknown. We have previously identified cell layer-specific mutants for the petal identity gene PhDEF in petunia flowers, resulting in drastically different petal phenotypes whether PhDEF is expressed in the petal epidermis or in the mesophyll. In this study, using a combination of single-cell RNA-Seq and chromatin immunoprecipitation on phdef cell layer-specific mutants, we find that PhDEF regulates a different set of target genes in the petal epidermis and mesophyll, with a major regulatory action in the epidermis. We uncover a high diversity of binding profiles in PhDEF target genes, with a complex combination of layer-specific or non-specific binding sites, and a much more prominent binding of PhDEF in the epidermis than in the mesophyll. Our study highlights that floral homeotic genes like PhDEF can have different regulatory actions in different cell contexts, here different cell layers, demonstrating that cell layer identity indeed influences the regulatory processes underlying homeotic identity.

developmental biology↗

bioRxiv2021

Cell layer-specific expression of the B-class MADS-box gene PhDEF drives petal tube or limb development in petunia flowers

Floral homeotic MADS-box transcription factors ensure the correct morphogenesis of floral organs, which are organized in different cell layers deriving from the meristematic L1, L2 and L3 layers. How cells from these distinct layers acquire their respective identity and coordinate their growth to ensure normal floral organ morphogenesis is unresolved. Here, we study petunia petals that form a limb and tube through congenital fusion, a complex morphology that coevolved with pollinators. We have identified petunia mutants expressing the B-class MADS-box gene PhDEF in the epidermis or in the mesophyll of the petal only, called wico and star respectively. Strikingly, wico flowers form a strongly reduced tube while their limbs are almost normal, while star flowers form a normal tube but very reduced and unpigmented limbs, showing that petunia petal morphogenesis is highly modular. Comparative transcriptome analysis of star, wico and wild-type petals revealed a strong down-regulation of the anthocyanin production pathway in star petals including its major regulator ANTHOCYANIN2 (AN2). We found that PhDEF directly binds to AN2 regulatory sequence in vitro by gel shift assay, and in vivo by chromatin immunoprecipitation, suggesting that PhDEF directly activates the petal pigmentation pathway by activating AN2. Altogether, we show that cell-layer specific homeotic activity in petunia petals differently impacts tube and limb development, revealing the relative importance of the different cell layers in the modular architecture of petunia petals.

plant biology↗