title: Degradation of Biofumigant Isothiocyanates and Allyl Glucosinolate in Soil and Their Effects on the Microbial Community Composition.
abstract: Brassicales species rich in glucosinolates are used for biofumigation, a process based on releasing enzymatically toxic isothiocyanates into the soil. These hydrolysis products are volatile and often reactive compounds. Moreover, glucosinolates can be degraded also without the presence of the hydrolytic enzyme myrosinase which might contribute to bioactive effects. Thus, in the present study the stability of Brassicaceae plant-derived and pure glucosinolates hydrolysis products was studied using three different soils (model biofumigation). In addition, the degradation of pure 2-propenyl glucosinolate was investigated with special regard to the formation of volatile breakdown products. Finally, the influence of pure glucosinolate degradation on the bacterial community composition was evaluated using denaturing gradient gel electrophoresis of 16S rRNA gene amplified from total community DNA. The model biofumigation study revealed that the structure of the hydrolysis products had a significant impact on their stability in the soil but not the soil type. Following the degradation of pure 2-propenyl glucosinolate in the soils, the nitrile as well as the isothiocyanate can be the main degradation products, depending on the soil type. Furthermore, the degradation was shown to be both chemically as well as biologically mediated as autoclaving reduced degradation. The nitrile was the major product of the chemical degradation and its formation increased with iron content of the soil. Additionally, the bacterial community composition was significantly affected by adding pure 2-propenyl glucosinolate, the effect being more pronounced than in treatments with myrosinase added to the glucosinolate. Therefore, glucosinolates can have a greater effect on soil bacterial community composition than their hydrolysis products.
authors.affiliation: Department of Quality, Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V., Theodor-Echtermeyer-Weg 1, D-14979 Grossbeeren, Germany.
authors.forename: Franziska S
authors.initials: FS
authors.lastname: Hanschen
authors.affiliation: Institute of Horticultural Production Systems, Leibniz Universität Hannover, Section of Woody Plant and Propagation Physiology, Herrenhäuser Str. 2, D-30419 Hannover, Germany; Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut - Federal Research Centre for Cultivated Plants (JKI), Messeweg 11-12, D-38104 Braunschweig, Germany.
authors.forename: Bunlong
authors.initials: B
authors.lastname: Yim
authors.affiliation: Institute of Horticultural Production Systems, Leibniz Universität Hannover, Section of Woody Plant and Propagation Physiology, Herrenhäuser Str. 2, D-30419 Hannover, Germany.
authors.forename: Traud
authors.initials: T
authors.lastname: Winkelmann
authors.affiliation: Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut - Federal Research Centre for Cultivated Plants (JKI), Messeweg 11-12, D-38104 Braunschweig, Germany.
authors.forename: Kornelia
authors.initials: K
authors.lastname: Smalla
authors.affiliation: Department of Quality, Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V., Theodor-Echtermeyer-Weg 1, D-14979 Grossbeeren, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Schreiner
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D016000:Cluster Analysis; D005651:Fumigation; D005961:Glucosinolates / Q000378:metabolism*; D006868:Hydrolysis; D017879:Isothiocyanates / Q000378:metabolism*; D007700:Kinetics; D012987:Soil / Q000737:chemistry*
chemical_list: D005961:Glucosinolates; D017879:Isothiocyanates; D012987:Soil; C037152:isothiocyanic acid