IMPROVEMENT OF SEED AND END-USE QUALITY OF COOL SEASON GRASSES
Location: Forage Seed and Cereal Research
Title: 4-Formylaminooxyvinylglycine, an Herbicidal Germination-Arrest Factor (GAF) from Pseudomonas Rhizosphere Bacteria
Submitted to: Journal of Natural Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 4, 2010
Publication Date: October 27, 2010
Citation: Mcphail, K.L., Armstrong, D.J., Azevedo, M.D., Banowetz, G.M., Mills, D.J. 2010. 4-Formylaminooxyvinylglycine, an Herbicidal Germination-Arrest Factor (GAF) from Pseudomonas Rhizosphere Bacteria. Journal of Natural Products. 73:1853-1857.
Interpretive Summary: The structure of a compound derived from a soil bacterium that arrests the germination of grassy weeds has been determined. The compound, called Germination Arrest Factor (GAF for short) irreversibly arrests the germination of a wide variety of grassy weeds that occur in cereal and grass seed production fields as well as recreational turfs. Until now, the structure of the compound was unknown and as a consequence, production of the compound for use in agricultural settings has not been possible. This research describes in detail the structure of GAF, a novel compound that has not been described in the past.
A new oxyvinylglycine has been identified as a naturally occurring herbicide that irreversibly arrests germination of the seeds of grassy weeds; such as annual bluegrass (Poa annua), without significantly affecting the growth of established grass seedlings and mature plants, or germination of the seeds of broadleaf plant species (dicots). Previously, Pseudomonas fluorescens WH6 and over twenty other rhizosphere bacteria were isolated and selected for their ability to arrest germination of P. annua seeds. The Germination-Arrest Factor (GAF, 1) responsible for this developmentally specific herbicidal action has now been isolated from the culture filtrate of P. fluorescens WH6. Purification of this highly polar, low molecular weight natural product allowed its structure to be assigned as 4-formylaminooxy-Lvinylglycine based on NMR spectroscopic and mass spectrometric data, in combination with D/L-amino acid oxidase reactions to establish the absolute configuration. Assay results for P. annua inhibition by related compounds known to regulate plant growth are presented, and a cellular target for 1 is proposed. Furthermore, using bioassays, TLC, and capillary NMR spectroscopy, it has been shown that GAF (1) is secreted by all other herbicidally-active rhizosphere bacteria in our collection.