The relationship between pathogenic fungal metabolities (fusaric and picolinic acid), endogenous ethylene evolution and the development of ethylene-like symptoms

Abstract

The effects of fusaric acid (5-n-butylpicolinic acid), picolinic acid (2-pyridine carboxylic acid), and picloram (4-amino-3, 5, 6-trichloropicolinic acid) on endogenous ethylene production by tomato cuttings and elongation growth of oat coleoptile sections were measured. Ethylene production by tomato cuttings was substantially stimulated by treatment with 1×10−3 and 1×10−5M picoloram and to a lesser extent by 1×10−3M fusaric acid; picolinic acid had little effect. The ethylene levels produced in response to fusaric acid are not high enough to account for the ethylene injury observed in Fusarium wilt. Fusaric acid inhibited oat coleoptile extension, picolinic acid had little effect, and picloram promoted growth.