A New Method for Measuring β-1, 3-Glucanase Activity Using p-Nitrophenyl-β-D-laminaritetraoside as a Substrate to Diagnose Verticillium Wilt of Eggplant

Abstract

A new method for analysing β-1, 3-glucanase activity was developed, to replace the somewhat complicated DNS method which is currently used to measure β-1, 3-glucanase activity. A new method, the pNPG4 degradation method, using p-nitrophenyl-β-D-laminaritetraoside (pNPG4) as a substrate was easier and more precise than the DNS method. We measured β-1, 3-glucanase activity on diseased eggplants with the pNPG4 degradation method. The enzyme activity of leaves in eggplants infected with Verticillium dahliae increased up to 1.5 times that in healthy plants, from 4 days before to 1 day after symptom appearance. The activity in naturally infected eggplants increased as well when the symptoms appeared in parts of the plants. Therefore, Verticillium wilt of eggplant can be diagnosed by measuring β-1, 3-glucanase activity using the pNPG4 degradation method.