Role of auxin-amidohydrolases in solanaceae plants

D IPPÓLITO, SEBASTIAN; FIOL, DIEGO; CASALONGUÉ, CLAUDIA

Puerto Madryn

Congreso; XLVI reunión anual de SAIB; 2010

SAIB

Auxins regulate plant development, growth and responses to the environment. A cDNA clone coding for StIAR3, an auxin-conjugate amidohydrolase, was isolated from a potato library in our laboratory. StIAR3 is up-regulated upon different biotic stress suggesting its role in plant-pathogen interactions. In order to analyze the involvement of StIAR3 in the resistance mechanism of Nicotiana benthamiana plants we carried out a functional genomic strategy using Virus-Induced Gene Silencing (VIGS) to knock-down amidohydrolase gene expression. Phenotypical analysis evidenced an altered growth pattern in IAR3 silenced plants. It was correlated with reduced StIAR3 transcript levels measured by RT-PCR. In addition, bioassays performed with Phytophthora infestans were carried out in order to evaluate the hypersensitive response (HR) in silenced and control plants. A differential HR susceptibility was evidenced 5 days after inoculation by examining visible necrotic spots between non-silenced and silenced tobacco leaves. These results will allow us to evaluate the impact of amidohydrolases and auxin balance in the plant defense response to fungal pathogens.