Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: April 8, 2004
Publication Date: September 1, 2003
Citation: Masler, E.P., Chitwood, D.J., Kovaleva, E.S. 2003. An aldolase gene from the cyst nematodes heterodera glycines and globodera rostochiensis. J. Nematology 35: 352.
Fructose-bisphosphate aldolase (E.C. 126.96.36.199) is the key enzyme of the sixth step of glycolysis. Aldolase isozymes take part in developmental stage-specific and tissue-specific sugar phosphate metabolism. The expression levels often correlate with diet or other environmental conditions; therefore, the enzyme may regulate important aspects of pathogenesis in plant-parasitic nematodes. Here we report the isolation and characterization of full-length coding sequences for aldolase from the cyst nematodes Heterodera glycines and Globodera rostochiensis. The respective sequences encode 40-kilodalton secretory proteins of 366 and 365 amino acids. The homology of the two deduced proteins is very high: 89% amino acid identity. Comparison with available amino acid sequences from other nematodes revealed that both proteins from cyst nematodes have higher homology to aldolase 2 (Ce-2) rather than aldolase 1 (Ce-1) from Caenorhabditis elegans or aldolase from Onchocerca volvulus (72, 60 and 61% amino acid identity, respectively). Total aldolase-like activity in tissue extracts from H. glycines and C. elegans was quantified by spectrophotometric assay using fructose-1,6-biphospate as the substrate. The measured affinity was similar for both species (Km in micromolar range), whereas the amount was much greater for C. elegans than for any developmental stage of H. glycines. Inhibition analysis also revealed metabolic differences between the species. Experiments are underway to examine the effects of diet on the activity of aldolase. For H. glycines this is achieved by exposure of soybean plants to conditions that retard root growth such as reduced light or leaf removal.