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Physiology and Biochemistry

Gibberellin A₄ Production by Sphaceloma manihoticola, Causal Agent of Cassava Superelongation Disease. R. S. Zeigler, Graduate research assistant, Department of Plant Pathology, Cornell University, Ithaca, NY 14853; L. E. Powell(2), and H. D. Thurston(3). (2)Professor, Department of Pomology, Cornell University, Ithaca, NY 14853; (3)Professor Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 70:589-593. Accepted for publication 2 November 1979. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-589.

Symptoms of superelongation disease of cassava (caused by Sphaceloma manihoticola), include striking internode elongation, suggesting a hormonal role in the disease. Gibberellin A₄ was purified from culture filtrate of pathogenic isolates by base-acid partitioning with ethyl acetate followed by silica gel column chromatography. Biologically active fractions were identified by lettuce seedling hypocotyl elongation bioassay. The fungal product was identified as gibberellin A₄ by combined gas-liquid chromatography and mass spectrometry. Treatment of plants with known gibberellin A₄ and that purified from pathogen filtrate reproduced secondary symptoms.