Role of auxin-amidohydrolases in solanaceae plants

D IPPOLITO, S.; FIOL DF; CASALONGUE CA

Mar del Plata

Congreso; VIII congreso argentino de microbiologia; 2012

SAMIGE

Role of auxin-amidohydrolases in solanaceae plants In our laboratory a Solanum tuberosum IAR3 cDNA, StIAR3, coding for an auxin-conjugate amidohydrolase was isolated from a potato cDNA library. StIAR3 is up-regulated upon different biotic stress conditions suggesting its putative role in plant-pathogen interactions. In order to analyze the involvement of amidohydrolases 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. Altered growth pattern was evidenced in IAR3 silenced plants. It was correlated with reduced StIAR3 transcript levels measured by RT-PCR and with the reduced free IAA content in silenced plants. In addition, bioassays with Phytophthora infestans were performed to evaluate the hypersensitive response (HR) in silenced and control plants. Differential susceptibility to HR was evidenced 5 days after inoculation by examining visible necrotic spots between non-silenced and silenced tobacco leaves. In addition we observed changes in the level expression of genes implicated in the HR development in amidohydrolase- silenced plants. These results will allow us to evaluate the impact of amidohydrolases and auxin balance in the plant defense response to fungal pathogens.    Supported by UNMdP and CONICET