A 4,5-UNSATURATED LOW-MOLECULAR OLIGOGALACTURONIDE AS A POTENT PHYTOALEXIN-ELICITOR ISOLATED FROM POLYGALACTURONIDE OF FICUS-AWKEOTSANG

A highly methyl esterified linear ∞-(1→4)-linked polygalacturonide, isolated from a water extract of seeds of Ficus awkeotsang Makino, was used for the study of elicitor-active oligosaccharides on host-parasite interactions in higher plants. Oligogalacturonides (OLGAs), obtained from awkeotsang polygalacturonide or low methyl esterified apple pectin by treatment with the purified endo-pectate lyase (EC 4.2.2.2) of Erwinia carotovora, were found to induce glyceollin accumulation in soybean cotyledons. The de-esterified awkeotsang-OLGAs was precisely fractionated by anion-exchange chromatography using a QA”E-Sephadex A-25 column, and was assayed for the elicitor activity. Among the purified oligogalacturonides with DP 3 to 12, it was found that 4,5unsaturated hexa-∞-1,4-galacturonide of the low molecular elicitor-active oligogalacturonides (DP 5 to 7) also was a potent elicitor as well as the 4,5-unsaturated deca-(l-1,4-galacturonide of the high molecular elicitor-active oligogalacturonides (DP 9 to 11) previously reported by Davis et al.1. © 1990 by the Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.