The AtPNP-R1 receptor interacts with plant (AtPNP-A) and bacterial (XacPNP) type natriuretic peptides.

DI PAOLO, VALERIA; MASOTTI, FIORELLA; GARAVAGLIA, BETIANA S.; GOTTIG, NATALIA

Mendoza

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

Natriuretic Peptide (NP) systems have been identified in many vertebrates and are associated with osmoregulatory homeostasis. In higher plants, PNPs are heterologous of animal NPs and elicit a number of responses that ar e essential in solute and solvent homeostasis and responses to biotrophic pathogens. The Arabidopsis thaliana PNP, AtPNP A, interacts whit a leucine rich repeat protein denominated AtPNP R1. Through this interaction, is able to trigger different responses in plant, to adapt to changes in the environment and regulate internal homeostasis.Xanthomonas citri subsp. citri , the biotrophic bacterial pathogen responsible for citrus canker, also has a PNP like protein named XacPNP. Our previous results support the hypothesis that XacPNP mimics AtPNP A in eliciting physiological responses in plants, such as stomatal opening, increases in net water flux and sustains photosynthesis during the early stage of pathogenic infection. We align the tertiary structures to AtPN P A y XacPNP, obtained in silico , and we determined that these are similar even though their amino acid sequences have a percentage of identity of 49%. To mention is that amino acids are conserved within the active domain. This, together with previous resu lts, is compatible with the hypothesis of horizontal gene transfer.We were able to determined quantitatively that the receptor AtPNP R1 is associated with the plasma membrane in plant epidermal cells and it moves along the membrane and also, intracellular ly. For this, we expressed the construct AtPNP R1 Venus, we labelled the plasma membrane with FM4 64 label and we performed colocalization analyses and plasmolysis assays. Also, we analysis the interactions between constructs AtPNP Turquoise AtPNP R1 Ven us and XacPNP Turquoise AtPNP R1 Venus in planta using colocalization and FRET assays.