MAMP pre-treatment compromises effector induced suppression of
cROS.
The chloroplastic ROS (cROS) burst has emerged as an important component
of plant immunity, as evidenced by early DC3000 effector delivery to
attenuate the MTI induced cROS burst (de Torres Zabala et al. ,
2015). Therefore, to assess the relationship betweenFv/Fm and cROS production and
thus the role of DC3000 effectors in this process, leaves were treated
with the non-specific ROS reporter, 2′7′-dichlorodihydrofluorescein
diacetate (H2DCF-DA), to image cROS following DC3000
infection. Strong cROS induced following DC3000hrpA infection was
evident 4.5 hpi whereas at this time cROS was minimal in DC3000
challenged leaves (Figure 3A, B). Notably, flg22 or elf18 pre-treatment
of leaves prior to DC3000 infection showed cROS at 4.5 hpi (Figure 3C,
D) indicating that the effectors secreted during DC3000 infection could
not dampen cROS within a primed leaf.