Role of the miR156/SQUAMOSA Promoter-Binding Protein-Like (SPL) pathway in growth and development of Passiflora cincinnata Mast. (Passifloraceae)

• Ano de defesa: 2022
• Autor(a) principal: Moncaleano Robledo, Kerly Jessenia
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Botânica - Morfologia; Passiflora - Desenvolvimento; Marcadores genéticos; Gavinhas; Nectários; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/30747; https://doi.org/10.47328/ufvbbt.2023.098

Post-embryonic plant development can be divided into vegetative, juvenile, adult, and reproductive phases. The transition of these phases is modulated by exogenous and endogenous factors, with the microRNA156 (miR156) pathway playing a central role in maintaining the juvenile phase by regulating genes of the SQUAMOSA PROMOTER-BINDING PROTEIN- LIKE (SBP/SPL) family of transcription factors. In the process of phase transition, multiple phenotypic changes occur, and in Passiflora cincinnata, besides leaf changes, the appearance of tendrils stands out. These structures are of great physiological and ecological relevance by favoring the performance and mutualistic interactions, e.g., with herbivores or pollinators and competition for resources with other species. However, the genetic and molecular control of their development is still unknown, as well as the possible role of miR156 in the growth and development of such structures. Thus, P. cincinnata is an excellent model for studying the molecular basis of nectaries and tendril development. It is necessary to generate overexpression (OE::miR156) and silencing (STTM156) lines that facilitate understanding the effects of the miR156/SPLs module. Our results show that in P. cincinnata, inhibition in phase transition is reflected in the maintenance of the juvenile stage in OE::miR156 plants compared to untransformed lines (NT). The miR156/SPL module affected the growth of tendrils. In OE::miR156 plants, initial development is maintained at the same growth rate as NT, but development is inhibited upon reaching approximately one- third of growth. In contrast, there is a continuity of growth in NT and silenced lines. Likewise, the emission of the first tendril did not show dependence on miR156 levels and represented the adult stage as believed, being more linked to the number of developed phytomers. Being a climbing specie is essential to emit this organ early in development to find support and allow resource exploitation. On the other hand, in the OE::miR156 plants, the leaves were permanently juvenile, which for P. cincinnata corresponds to trilobed leaves, contrasting with NT and the silenced lines that when transitioning phase issued pentalobed leaves. In later phytomeres, pentalobate leaves show greater complexity in NT plants, and this is accompanied by a greater number of nectaries, in contrast to the silenced lines. Demonstrating that leaf and nectary development are closely related. Thus, our observations show that miR156 affects the growth and development of nectaries and tendrils in P. cincinnata, and there is fine regulation by the aging pathway. Keywords: Passiflora. miRNA. Tendrils. Extrafloral nectaries. Development.