A PLANT NATRIURETIC PEPTIDE-LIKE PROTEIN FROM A BACTERIAL PHYTOPATHOGEN INVOLVED IN HOST RESPONSE

BETIANA GARAVAGLIA; NATALIA GOTTIG; LUCAS DAMIÁN DAURELIO; ELENA GRACIELA ORELLANO; JORGELINA OTTADO

Mar del Plata

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2007

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Natriuretic peptides are peptide hormones present in vertebrates involved in the regulation of salt and water homeostasis. In plants, natriuretic peptides (PNP) have been discovered with similar biological activities modulating plant water and solute homeostasis. Xanthomonas axonopodis pv. citri,  the bacterial phytopathogen responsible for citrus canker, has a PNP-like protein (XacPNP) that shares significant sequence similarity and identical domain organization with PNPs. In this study we expressed and purified XacPNPin order to investigate whether it is biologically active and able to modify plant cell homeostasis during the pathogenic process. XacPNP showed a role in citrus leaves stomatal aperture and photosynthetic efficiency. XacPNP expression in citrus leaves during the infection process was observed by RT-PCR. Our results show that XacPNP acts as an active peptide, that it is expressed during the interaction with the host plant and thus has a role in the plant-pathogen interaction. Together, these findings provide strong evidence that XacPNP has a role in plant cell homeostasis suggesting that this probably laterally acquired protein assists the pathogen in the manipulation of plant responses in order to create favourable conditions for its survival on the host.