Abstract
Leaf variegation is derived from a formation of sectors that contain either chloroplasts or undifferentiated plastids. Due to the presence of chlorophyll-deficient white sectors, leaf variegation negatively affects on photosynthetic capacity and growth. However, because leaf variegation is naturally found in many plant species, it might have advantageous for plant survival to overcompensate for lack of photosynthetic activity. Arabidopsis leaf-variegated mutant var2 results from the loss of FtsH2, a metalloprotease localized in thylakoid membranes and critically involved in the quality control of chloroplastic proteins. var2 causes the accumulation of ROS in chloroplasts of green sectors, while ROS have the effect as a bactericide. Interestingly, both green and white sectors repressed proliferation of Pst DC3000, although the increased resistance was not associated with higher levels of salicylic acid or defense-related genes. We discuss about high levels of ROS-scavenging enzymes in white sectors.
