Changes in amino-acid content of tomato xylem sap following infection with strains of Verticillium albo-atrum

Abstract

Xylem exudates of four tomato cultivars showing resistance and susceptibility to the vascular pathogen Verticillium albo-atrum, were analysed for amino acids and amides by column chromatography 42 days after inculation with different isolates of the fungus. Analysis of the exudate from healthy, resistant Loran Blood showed a substantial reduction in amino compounds compared with the healthy, susceptible Potentate and Bonny Best. Resistant Moscow, however, gave similar results to Potentate. Infection in all cultivars except Moscow led to a general increase in the concentration of amino acids and predominantly in aspartic and glutamic acids, threonine, serine, proline, tyrosine, ornithine, lysine, histidine, and phenylalanine. A reduction in proline content of up to 90 per cent occurred in the resistant plants in both pathogenic and non-pathogenic combinations. The results are discussed in relation to previously published data on vascular colonization and disease development with the same tomato cultivers and fungal strains. © 1972 OXFORD UNIVERSITY PRESS.