Role of auxin-amidohydrolases in solanaceae plants

D IPPÓLITO S; FIOL DF & CASALONGUÉ CA

Puerto Madryn

Congreso; XLVI Congreso de la Sociedad Argentina de Bioquímica y Biología Molecular; 2010

Auxins regulate plant development, growth and responses to theenvironment. A cDNA clone coding for StIAR3, an auxin-conjugateamidohydrolase, was isolated from a potato library in our laboratory.StIAR3 is up-regulated upon different biotic stress suggesting its rolein plant-pathogen interactions. In order to analyze the involvementof StIAR3 in the resistance mechanism of Nicotiana benthamianaplants we carried out a functional genomic strategy using Virus-Induced Gene Silencing (VIGS) to knock-down amidohydrolasegene expression. Phenotypical analysis evidenced an altered growthpattern in IAR3 silenced plants. It was correlated with reducedStIAR3 transcript levels measured by RT-PCR. In addition,bioassays performed with Phytophthora infestans were carried outin order to evaluate the hypersensitive response (HR) in silenced andcontrol plants. A differential HR susceptibility was evidenced 5 daysafter inoculation by examining visible necrotic spots between nonsilencedand silenced tobacco leaves. These results will allow us toevaluate the impact of amidohydrolases and auxin balance in theplant defense response to fungal pathogens.Supported by UNMdP and CONICET.