Persistence of Induced Systemic Resistance to Blue Mold in Tobacco Plants Derived Via Tissue Culture

Abstract

Injecting sporangia of Peronospora tabacina, the blue mold pathogen, into tobacco [Nicotiana tabacum] stem tissue external to xylem systemically protected foliage against blue mold. Plants derived via tissue culture from leaves and leaf midribs of parents injected with P. tabacina were also systemically protected against the disease. Protection was expressed as a reduction in sporulation on younger plants, whereas a reduction of symptom severity and sporulation were observed on older plants. Data were obtained for greenhouse and field experiments. Immunization was not transferred via seed of stem injected plants nor via seed from plants derived from tissue culture of stem-injected plants. Induced resistance increases with age of tissue culture-derived plants and, in this respect, resembles the increase in resistance to blue mold of nonstem-injected resistant and susceptible cultivars.