Phytoalexin synthesis in the juvenile sorghum leaf

• Published in: Physiological and molecular plant pathology Vol. 33; no. 2; pp. 271 - 278
• Main Authors: Nicholson, Ralph L., Jamil, Farhat F., Snyder, Beth A., Lue, Wei Ling, Hipskind, John
• Format: Journal Article
• Language: English
• Published: London Elsevier India Pvt Ltd 01.09.1988; Elsevier
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; Anthocyanin; Colletotrichum graminicola; Monocotyledones; Mycosis; Biochemical compound; Bipolaris maydis; Biosynthesis; Plant leaf; Phytopathogen; Cyanogenic glucoside; Cereal crop; Fungus resistance; Fungi; Infection; Sorghum bicolor; Gramineae; Phytoalexin; Angiospermae; Apathogenic; Pigments; Spermatophyta; Fungi Imperfecti; Thallophyta
• ISSN: 0885-5765; 1096-1178
• DOI: 10.1016/0885-5765(88)90027-6

Infection of the juvenile sorghum leaf by Colletotrichum graminicola (a pathogen) and Helminthosporium maydis (a non-pathogen) resulted in the rapid accumulation of a phytoalexin pigment complex previously identified from the sorghum mesocotyl. The principal pigments have been identified as the 3-deoxyanthocyanidins, apigeninidin and luteolinidin, but the complex includes several as yet unidentified pigment components. After the onset of penetration, components of the complex rapidly accumulated to nanogram levels within a highly restricted area at the infection site. Because of the speed of synthesis, occurrence in response to attempted infection, and previously reported fungitoxicity of the components, we propose that synthesis of the pigment complex constitutes a defense response in the juvenile sorghum leaf. The results show that the preformed cyanogenic glycoside, dhurrin, is not the only source of resistance of sorghum seedlings to fungal infection.