The primary structures of one elicitor-active and seven elicitor-inactive hexa(beta-D-glucopyranosyl)-D-glucitols isolated from the mycelial walls of Phytophthora megasperma f. sp. glycinea.

The primary structures of eight hexa(beta-D-glucopyranosyl)-D-glucitols purified from partially hydrolyzed Phytophthora megasperma f. sp. glycinea mycelial walls were determined by microscale glycosyl-sequence analysis. The elicitor-active hexa(beta-D-glucopyranosyl)-D-glucitol had the following structure: (Formula: see text) The similarity in structure of six of the elicitor-inactive hexa(beta-D-glucopyranosyl)-D-glucitols to the elicitor-active hexa(beta-D-glucopyranosyl)-D-glucitol established that a highly defined structure is required for elicitor activity. The elicitor-active hexa(beta-D-glucopyranosyl)-D-glucitol is the first example of a complex carbohydrate acting as a regulatory molecule in plants.