The holistic approach

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Conventionel cultivation - Stakado FATEALLCHEM Output Compounds produced and used for studies • Pure benzoxazinoid soil metabolites: MBOA, BOA, AP, APO, AMPO; AAPO, AAMPO, HPMA, HMPMA, HPAA, HHPAA** • Pure benzoxazinoid standards isolated from wheat: DIMBOA-glc, DIBOA-glc, DIMBOA, DIBOA, HBOA, HMBOA, MBOA, BOA** • New synthetic benzoxazinoid derivates for patents identified **systematic names, see www.fateallchem.dk The holistic approach in allelopathy research Fate and toxicity of allelochemicals (natural plant toxins) in relation to environment and consumer QLK5-CT-2001-01967) (FATEALLCHEM, A Oliveros-Bastidas, A M Simonet, J Fritz, D Barceló, E Eljarrat, L Bonnington, M Guillamon, M Villagrasa, A Taberner, O Sakaliene, B B Mogensen, T Krongaard, W Oleszek, J Kus, S Martyniuk, A Stochmal I S Fomsgaard*, L M Hansen, P Kudsk, S Mathiassen, A M Mortensen, M Gents, A Understrup, S T Nielsen, S S Krogh, S Mensz, C Christophersen, E Benfenati, E Lo Piparo, F Fratev, S Blümel, T Coja, J Idinger, FA Macías, D Chinchilla, D Marín, J M G Molinillo, Output Output Why? Toxicological effects, Folsomia candida • Lethal effects: APO, HPAA, AAPO>AMPO, AAMPO>DIMBOA>MBOA>BOA • Sublethal effects:AMPO, AAMPO>APO, AAPO, HPAA>DIMBOA>MBOA>BOA Toxicological effects, Poecilus cupreus • Lethal effects: APO, HPAA, AAPO>BOA. No lethal effects: AMPO, AAMPO, DIMBOA, MBOA. • Sublethal effects: None General conclusions: maximum concentrations of the allelochemicals supposed to be present in the soil under field conditions did not pose an unacceptable risk to the tested standard soil arthropods Allelopathy has received new attention in modern research. Targeted use of the allelopathic properties of plants could lead to a reduction of the use of synthetic pesticides. However, modern analytical techniques and a holistic approach is needed for a thorough evaluation of exploitation strategies. Variations in levels of benzoxazinoids in plants • between varieties (Stakado, Ritmo and Astron); highest level in Stakado • between farming systems (but not consistent) • between growth stages (highest concentration in young plants) • between root and foliage (see Figure 1) Figure 1. Distribution in % of allelochemical compounds between foliage and root. % Output Aim? • to perform an environmental and human risk assessment of exploiting the allelopathic properties of wheat in modern farming • and • to develop a framework for future assessments of allelopathic crops. Suppessive effects on fungi, ID50 (µg/ml) • Cephalosporium gramineum: • APO 0.58; AAPO 4.57; AP 1.4 µg/ml______HPAA, AAMPO, HMPMA, HPMA, HMBOA : no effects • Gaumannomyces graminis var tritici • APO 0.78; AAPO 2.18; AP 0.80 µg/ml_____ HPAA, AAMPO, HMPMA, HPMA, HMBOA : no effects • Fusarium culmorum: no effects Growth stage (BBCH) Output Views and prospects How? Suppressive effects (pure compounds) on weeds and crops • Most affected:Root length>shoot length>germination • Most active: • APO (soil metabolite) • Synthetic derivatives • DIMBOA and DIBOA (note: DT50 <1 day) Figure 4.Effect of benzoxazinoid metabolites on root length of wild oat compared to the commercial herbicide Logran How can we exploit the allelopathic properties of cereals? • Using rye or wheat as catch crops in vegetable production • Optimizing sowing time • Optimizing choice of variety of cereal • Breeding for wheat and rye varieties with higher concentrations • Search for varieties with optimal combination between content of benzoxazinoids and other allelochemicals • Producing benzoxazinoid derivatives as new lead molecules What is needed for assessment of extensive use of allelopathic crops? • Validated sensitive analytical methods • Considerations of relevant concentration levels • Studies on soil processes • Toxicological evaluations (environment, humans) • Effect studies on weeds, crops, fungi and pests • Studies on isolated compounds, mixtures as well as natural systems • Molecular modelling (QSAR) • Isolation and synthesis of compounds • Development of sensitive, intercalibrated analytical methods in LC-MS • Determination of levels of benzoxazinoids in wheat varieties grown in different conditions • Suppressive effects on weeds, crops, fungi and pests • Fate and ecotox studies studies • Toxicology evaluation for humans and mammals • QSAR modelling • Economic evaluation Output Leaching from plants Figure 2. Leaching of benzoxazinoids from soil-incorporated wheat (Stakado). DT50 for Benzoxazinoids <2 days Transformation in soil Figure 3. Transformation of BOA to APO in soil Output Inhibition of pests • Only half of the parasitic wasps will hatch on aphids who lived on a diet including 0.2 mM MBOA • Increasing concentrations of MBOA in artificial diets results in a decrease in intrinsic rate of increase of aphids • The concentration of MBOAin Stakado, Ritmo and Astron is not high enough for showing a significant inhibition of aphid growth rate • Other properties of wheat varieties lead to significant differences in rate of increase of aphids in late growth stages of the plants Thanks • To the European Commission (Quality of Life, Framework 5) for financial support • To our scientific officer, Mrs. Elzbieta Ceglarska, for valuable discussions *Danish Insitute of Agricultural Sciences, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark; This poster only presents selected results. Additional information: www.fateallchem.dk; Inge.Fomsgaard@agrsci.dk