Host-pathogen interactions. XXIX. Oligogalacturonides released from sodium polypectate by endopolygalacturonic acid lyase are elicitors of phytoalexins in soybean. [Glycine max L]
Recent studies have demonstrated that an apparently homogeneous preparation of an ..cap alpha..-1,4-D-endopolygalacturonic acid lyase (EC 4.2,2.2) isolated from the phytopathogenic bacterium Erwinia carotovora induced phytoalexin accumulation in cotyledons of soybean (Glycine max (L.) Merr. cv Wayne) and that this pectin-degrading enzyme released heat-stable elicitors of phytoalexins from soybean cell walls, citrus pectin, and sodium polypectate. The present paper reports the purification, by anion-exchange chromatography on QAE-Sephadex columns followed by gel-permeation chromatography on a Bio-Gel P-6 column, of the two fractions with highest specific elicitor activity present in a crude elicitor-preparation obtained by lyase treatment of sodium polypectate. Structural analysis of the fraction with highest specific elicitor activity indicated that the major, if not only, component was a decasaccharide of ..cap alpha..-1,4-D-galactosyluronic acid that contained the expected product of lyase cleavage, 4-deoxy-..beta..-L-5-threo-hexopyranos-4-enyluronic acid (4,5-unsaturated galactosyluronic acid), at the nonreducing terminus. This modified decagalacturonide fraction exhibited half-maximum and maximum elicitor activity at 1 microgram/cotyledon (6 micromolar) and 5 micrograms/cotyledon (32 micromolar) galactosyluronic acid equivalents, respectively. Reducing 90 to 95% of the carboxyl groups of the galactosyluronic acid residues abolished the elicitor activity of the decagalacturonide fraction. The second most elicitor-active fraction contained mostly undeca-..cap alpha..-1,4-D-galactosyluronic acid that contained 4,5-unsaturated galactosyluronic acid at the nonreducing termini. This fraction exhibited half-maximum and maximum elicitor activity at approximately 3 micrograms/cotyledon (17 micromolar) and 6 micrograms/cotyledon (34 micromolar) galactosyluronic acid equivalents, respectively.
- Research Organization:
- Univ. of Colorado, Boulder
- DOE Contract Number:
- AC02-76ER01426
- OSTI ID:
- 5620954
- Journal Information:
- Plant Physiol.; (United States), Vol. 80:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GALACTURONIC ACID
CHEMICAL COMPOSITION
LYASES
ENZYME ACTIVITY
BACTERIA
BIOLOGICAL ACCUMULATION
DECOMPOSITION
EXPERIMENTAL DATA
GELS
GLYCINE HISPIDA
HOST
ION EXCHANGE CHROMATOGRAPHY
LEAVES
METABOLITES
PATHOGENS
PECTINS
POLYSACCHARIDES
PURIFICATION
ALDEHYDES
BLOOD SUBSTITUTES
CARBOHYDRATES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHROMATOGRAPHY
COLLOIDS
DATA
DISPERSIONS
DRUGS
ENZYMES
HEMATOLOGIC AGENTS
HYDROXY ACIDS
INFORMATION
LEGUMINOSAE
MICROORGANISMS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
PLANTS
RHIZOBIUM
SACCHARIDES
SEPARATION PROCESSES
550200* - Biochemistry