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Publication Abstract from PubMed

Management of the agricultural pathogen soybean cyst nematode (SCN) relies on the use of SCN-resistant soybean cultivars, a strategy that has been failing in recent years. An underutilized source of resistance, in the soybean genotype Peking, is linked to two polymorphisms in serine hydroxy-methyltransferase 8 (SHMT8). SHMT is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that converts L-serine and (6S)-tetrahydrofolate (THF) to glycine and 5,10-methylenetetrahydrofolate. Here, we determined five crystal structures of the 1,884-residue SHMT8 tetramers from the SCN-susceptible cultivar (cv.) Essex and the SCN-resistant cv. Forrest (whose resistance is derived from the SHMT8 polymorphisms in Peking) were determined in complex with various ligands at 1.4 - 2.35 A resolutions. We find that the two Forrest-specific polymorphic substitutions (P130R and N358Y) impact the mobility of a loop near the entrance of the THF-binding site. Ligand-binding and kinetic studies indicate severely reduced affinity for folate and dramatically impaired enzyme activity in Forrest SHMT8. These findings imply widespread effects on folate metabolism in soybean cv. Forrest that have implications for combating the widespread increase in virulent SCN.

Impaired folate binding of serine hydroxymethyltransferase 8 from soybean underlies resistance to the soybean cyst nematode.,Korasick DA, Kandoth PK, Tanner JJ, Mitchum MG, Beamer LJ J Biol Chem. 2020 Feb 2. pii: RA119.012256. doi: 10.1074/jbc.RA119.012256. PMID:32014996^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.