Recently, the polar auxin transport in roots was reported to be targeted by an RXLR effector of P. parasitica, the Penetration-Specific Effector 1 (PSE1), in compatible interactions with A. thaliana roots [50], leading to modulation of the auxin content (possibly by lowering the auxin concentrations) locally at the root apex to favour infection. This evidence concerns the gene IPO5 and infection.