Phytoalexin synthesis by the sorghum mesocotyl in response to infection by pathogenic and nonpathogenic fungi

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 84; no. 16; pp. 5520 - 5524
• Main Authors: Nicholson, R.L, Kollipara, S.S, Vincent, J.R, Lyons, P.C, Cadena-Gomez, G
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01-08-1987; National Acad Sciences
• Subjects: Biological and medical sciences; Biological Sciences: Applied Biology; BIOSINTESIS; BIOSYNTHESE; BIOSYNTHESIS; COCHLIOBOLUS; COCHLIOBOLUS HETEROSTROPHUS; COLLETOTRICHUM; COLLETOTRICHUM GRAMINICOLA; DISEASE RESISTANCE; FITOALEXINA; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fungi; Infections; Inoculation; Mesocotyls; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; PHYTOALEXINE; PHYTOALEXINS; Phytopathology; Phytopathology. Animal pests. Plant and forest protection; Pigments; Plants; RESISTANCE AUX MALADIES; RESISTENCIA A LA ENFERMEDAD; Seedlings; Solvents; Sorghum; SORGHUM BICOLOR; VARIEDADES; VARIETE; VARIETIES; Colletotrichum graminicola; Monocotyledones; Mycosis; Biosynthesis; Phytopathogen; Cereal crop; Fungi; Antifungal agent; Sorghum bicolor; Gramineae; Angiospermae; Pigments; Fungi Imperfecti; Thallophyta; Pathophysiology; Bipolaris maydis; Vegetal microorganism relation; Host agent relation; Metabolism; Defense; Mesocotyl; Infection; Phytoalexin; Apathogenic; Pathogen strain; Plantlet; Spermatophyta; Biological accumulation; Cultivar
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.84.16.5520

Infection of the sorghum mesocotyl by Helminthosporium maydis (a nonpathogen) and Colletotrichum graminicola (a pathogen) resulted in the rapid accumulation of a pigment complex by two sorghum cultivars. The components of the complex were fungitoxic. The principal compounds have been identified as the 3-deoxyanthocyanidins apigeninidin and luteolinidin. Apigeninidin accumulated in both sorghum cultivars in response to infection and was the predominant pigment. Luteolinidin accumulated in only one of the cultivars. Because of the speed of synthesis, occurrence only in response to inoculation, and fungitoxicity of the individual components, we propose that synthesis of the pigment complex constitutes a defense response and that the compounds apigeninidin and luteolinidin should be considered as phytoalexins.