Characterization and bacterial colonization of maize glossy mutants.
L.M. MARCELL, J. Petersen, G.A. Beattie. Depts. of Plant Pathology and Microbiology, Immunology and Preventive Medicine, Iowa State University, Ames, IA 50014.

For many bacterial phytopathogens, large epiphytic populations can increase the incidence of foliar disease. The plant cuticle is the major point of contact for these populations and thus cuticular properties probably influence epiphytic growth and survival. We have examined 11 cuticular mutants of maize, designated glossy mutants, for their leaf surface hydrophobicity and the morphology and distribution of their epicuticular wax. Water droplet contact angle measurements indicated that the mutants had significantly reduced surface hydrophobicity. Scanning electron microscopy photomicrographs showed that the mutants differed in their wax crystal morphology, distribution, and/or surface area covered. Furthermore, as surface hydrophobicity decreased from the wild type, morphological differences increased. In preliminary studies, we observed differences in bacterial distribution, growth and survival following inoculation of 3 glossy mutants with a common corn epiphyte, Pantoea agglomerans, indicating that specific cuticular features may uniquely influence the ability of bacteria to establish and maintain epiphytic populations.