Reaction of Chenopodium quinoa leaves to infiltrated Xylella fastidiosa (Xf)

• Author(s): Bruening, George; Buzayan, J.; Civerolo, Ed; Jernstedt, J.; Re, E.;
• Abstract: A survey identified Chenopodium quinoa for its ability to be readily leaf-infiltrated with suspensions of Xf bacteria and to provide a reaction to such infiltration within days. A chlorosis developed within 48 hr that coincided with the infiltrated area of the leaf lamella. Xf suspensions at 106 to 108 cfu/ml or single Xf colonies suspended in 0.2 ml of water were sufficient for inducing chlorosis. Light microscopy of leaf sections from water-infiltrated and Xf suspension-infiltrated areas revealed Xf-induced bleaching of apparently otherwise intact chloroplasts in all photosynthetic cell types. Heating of Xf suspensions at 100 deg C for 20 min did not decrease chlorosis induction, suggesting that the activity results from a heat-stable elicitor. Heating suspensions of washed cells resulted in partial release of chlorosis-inducing activity in soluble form. The structure(s) of the chlorosis-inducing substance(s) is under investigation.
• Publication Date: Jun 2001
• Journal: Phytopathology