Stomatal closure, callose deposition, and increase of LsGRP1-corresponding transcript in probenazole-induced resistance against Botrytis elliptica in lily

Botrytis leaf blight caused by Botrytis elliptica (Berk.) Cooke, causes enormous loss in the cut-flower industry of lilies in Taiwan. Application of probenazole (3-allyloxy-1,2-benzisothiazole-1,1-dioxide) before fungal inoculation was shown to be effective in protecting Oriental lily cultivar Star Gazer from infection by B. elliptica. The protection occurred 1 day after probenazole treatment, achieved a significant level second day after treatment and was maintained at a high level for 14 days. Alterations in the pathogenic fungus and the host plant caused by probenazole treatment were examined. Probenazole treatment caused a reduction of conidial germination of B. elliptica to a lesser extent but a significant decrease of the fungal penetration rate. On the plant, a high ratio of foliar stomata appeared closed as induced by probenazole and such high ratio of closed stomata was maintained after inoculation with B. elliptica. As indicated by the effect of abscisic acid, stomatal closure would be one of the plant responses related to the reduction of B. elliptica infection by probenazole. A complex response can be induced following probenazole treatment in lily and the correlations with callose deposition and increase of LsGRP1-corresponding transcript are indicated.