An amino acid analogue: a novel type of allelochemical produced by selected fine leaf fescue (Festuca) species.
Bertin, Cecile*,1, Schroeder, Frank1, Weston, Leslie1, 1 Cornell University, Ithaca, NY
ABSTRACT- Research on allelopathy has resulted in the development of successful green strategies for weed management. Through a variety of field and laboratory experiments, our research has shown that fine leaf fescues, widely used turfgrasses in the U.S. and Europe, possess significant allelopathic potential. Our analysis using activity- guided fractionation of fescue root exudates showed that weed suppressive ability is associated with an amino acid analogue growth inhibitor, m-tyrosine. M-tyrosine accounts for most of the weed suppressive activity observed within extracted fine leaf fescue root exudates. M-tyrosine possesses a relatively simple structure and is currently available synthetically, suggesting this compound could have great value as a potential bioherbicide. At this time, we have performed experiments in the laboratory that show that m-tyrosine is a selective inhibitor of turf weed growth, suppressing radicle elongation by influencing mitosis and cell division in a number of small seeded turf weeds including large crabgrass (Digitaria sanguinalis L.), white clover (Trifolium repens L.) and dandelion (Taraxacum officinale L.). This compound is also active in amended soil at low levels with activity observed at 1mM or higher. In addition, environmental conditions impact production of m-tyrosine and root exudation in fine leaf fescues. In particular, reduced moisture availability results in a 2 to 3 fold increase in production of m-tyrosine when fescue root exudates are produced using a capillary mat production system.. Currently, we are examining the specific mode of action of this compound in higher plants and the genes which regulate its biosynthesis in fine leaf fescue root cells.
Key words: allelopathy, festuca, m-tyrosine, fine leaf fescue
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