Oxalate-induced resistance of muskmelon to WMV-2

The treatment of muskmelon cultivar "Wangwenxiang", which is sensitive to w atermelon mosaic virus-2 (WMV-2), with oxalate increases systemic resistanc e of the cultivar to WMV-2 significantly, The challenge inoculation experim ents indicate that the symptom of oxalate-treated plant is much slighter th an that of control plants and the virus content is only 4% of that of contr ol plants. The peroxidase activity of oxalate-treated plant is six times of that of control plants; three new isoperoxidases are induced and lignin co ntent increases by 82.9%. These results indicate that oxalate induces syste mic resistance of muskmelon to WMV-2 while it induces increase of peroxidas e activity.