Changes in Levels and Isozymes of Peroxidase in Wounded Peach Bark

Abstract

Bark on one-yr-old branches from six peach cultivars was mechanically wounded then examined over time for changes in peroxidase isozymes, total peroxidase activity, and total protein. Four peroxidase isozymes were identified and changes in total activity were associated mostly with one isozyme. Changes in peroxidase activity in response to wounding were observed with activity increasing to the highest levels at 4 and 7 days post-wounding. At 10 and 14 days post-wounding, peroxidase levels had returned to levels similar to the control. An unidentified would response protein was detected in these experiments. The timing of the appearance of this protein was correlated with the known relative susceptibility of the cultivars to the peach canker pathogens, Leucostoma persooniiand L. cincta. Comparisons of the peroxidase isozyme profiles and total peroxidase activity among cultivars provided no indication that peroxidase profiles could be used as a marker for resistance to the peach canker pathogens.