Figure 4.

This PTR-MS-derived kinetic profile of VOCs of Arabidopsis roots infected with Pst DC3000 was analyzed during a time scan. Immediately after infection with Pst DC3000, the production of positive ions at several different masses increased significantly; this pattern continued until 40 h after infection. Section A shows the control measurement of the pure cultures of microorganisms in plant root culture media, in the absence of roots. Section B shows measurement results versus time of the untreated control Arabidopsis roots. Section C depicts the VOC measurement results versus time of the Pst DC3000-treated Arabidopsis roots. It was observed that some of the breakdown compounds such as ethyl acetate, acetic acid and 2-butanone were elicited for a longer duration post-Pst DC3000 infection. The monoterpene 1,8-cineole showed an instant spike post-Pst DC3000 infection followed by reduced titers until the end of the time scan at 40 h. Note: Eight different masses (compounds) were analyzed in each treatment (A–C) corresponding to the left and right sections.