TY  - JA
AU  - Egenolf,K.
AU  - Conrad,J.
AU  - Schöne,J.
AU  - Braunberger,C.
AU  - Beifuss,U.
AU  - Walker,F.
AU  - Nuñez,J.
AU  - Arango,J.
AU  - Karwat,H.
AU  - Cadisch,G.
AU  - Neumann,G.
AU  - Rasche,F.
TI  - Brachialactone isomers and derivatives of Brachiaria humidicola reveal contrasting nitrification inhibiting activity
SN  - 0981-9428
PY  - 2020///
CY  - Netherlands
PB  - Elsevier
KW  - Brachiaria humidicola
KW  - AGROVOC
KW  - Poaceae
KW  - Nitrification inhibitors
KW  - Forage
KW  - Savannas
KW  - Nitrosomonas europaea
N1  - Peer review
N2  - Biological Nitrification Inhibition (BNI) of Brachiaria humidicola has been mainly attributed to the root-exuded fusicoccane-type diterpene brachialactone. We hypothesized, however, that according to the high diversity of fusicoccanes described for plants and microorganisms, BNI of B. humidicola is caused by an assemblage of bioactive fusicoccanes. B. humidicola root exudates were collected hydroponically and compounds isolated by semi-preparative HPLC. Chemical structures were revealed by spectroscopic techniques, including HRMS as well as 1D and 2D NMR. Nitrification inhibiting (NI) potential of isolated compounds was evaluated by a Nitrosomonas europaea based bioassay. Besides the previously described brachialactone (1), root exudates contained 3-epi-brachialactone (2), the C3-epimer of 1 (m/z 334), as well as 16-hydroxy-3-epi-brachialactone (3) with an additional hydroxyl group at C16 (m/z 350) and 3,18-epoxy-9-hydroxy-4,7-seco-brachialactone (4), which is a ring opened brachialactone derivative with a 3,18 epoxide ring and a hydroxyl group at C9 (m/z 332). The 3-epi-brachialactone (2) showed highest NI activity (ED50 ~ 20 μg mL−1, ED80 ~ 40 μg mL−1), followed by compound 4 with intermediate (ED50 ~ 40 μg mL−1), brachialactone (1) with low and compound 3 without activity. In coherence with previous reports on fusicoccanes, stereochemistry at C3 was of high relevance for the biological activity (NI potential) of brachialactones
DO  - https://doi.org/10.1016/j.plaphy.2020.06.004
T2  - Plant Physiology and Biochemistry
ER  -