Investigating the Effect of Synthetic Auxin and an Auxin Transport Inhibitor on Phytophthora Pathogens

Abstract

Phytophthora infestans is a devastating disease that caused the unfortunate 1845 – 1852 Irish Famine, leading to 25% decline of the population of Irish people and still impacts the whole crop ecosystem in temperate potato growing regions. Therefore, scientists have been researching on preventions that are capable of preventing outbreaks and the spread of this pathogen. This project would like to investigate the role of the growth-promoting phytohormone auxin and auxin transport inhibitors in terms of crop protection against Phytophthora pathogens. In this project, the focus was on Phytophthora infestans. Several approaches were proposed in order to find a potential new prevention strategy. TIBA, IBA and SA were shown to inhibit the mycelial growth of P. infestans. TIBA and IBA were seen to induce the Phytophthora infestans induced-cell death. The negative activity of TIBA on both plant and pathogen in the Nicotiana benthamiana/Phytophthora infestans leaves led us to try and specifically target the putative target of TIBA in the pathogen using hairpin RNAi (hpRNAi). This project utilised a pHELLSGATE vector for host-induced gene silencing (HIGS) and a pSTORA vector for the transformation of P.infestans directly to examine the effect of specifically targeting the villin transcript in the pathogen for silencing.