PRF1 and infection: Interestingly, when using a needle inoculation method that introduces Pnss directly into the xylem and essentially bypasses the apoplast phase of the infection process, the Δrtx2 mutant strain did not cause wilting symptoms supporting our hypothesis that RTX2 has a pleiotropic role in plant host colonization as a cytolysin and an adhesin that is tissue-type specific.