Detection, isolation and characterization of a root-exuded compound, methyl 3-(4-hydroxyphenyl) propionate, responsible for biological nitrification inhibition by sorghum (Sorghum bicolor).
Nitrification results in poor nitrogen (N) recovery and negative environmental impacts in most agricultural systems. Some plant species release secondary metabolites from their roots that inhibit nitrification, a phenomenon known as biological nitrification inhibition (BNI). Here, we attempt to characterize BNI in sorghum (Sorghum bicolor). In solution culture, the effect of N nutrition and plant age was studied on BNI activity from roots. A bioluminescence assay using recombinant Nitrosomonas europaea was employed to determine the inhibitory effect of root exudates. One major active constituent was isolated by activity-guided HPLC fractionations. The structure was analysed using NMR and mass spectrometry. Properties and the 70% inhibitory concentration (IC(70)) of this compound were determined by in vitro assay. Sorghum had significant BNI capacity, releasing 20 allylthiourea units (ATU) g(-1) root DW d(-1). Release of BNI compounds increased with growth stage and concentration of supply. NH4+ -grown plants released several-fold higher BNI compounds than NO3- -grown plants. The active constituent was identified as methyl 3-(4-hydroxyphenyl) propionate. BNI compound release from roots is a physiologically active process, stimulated by the presence of NH4+. Methyl 3-(4-hydroxyphenyl) propionate is the first compound purified from the root exudates of any species; this is an important step towards better understanding BNI in sorghum.
Zakir
Hossain A K M
HAKM
Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Subbarao
Guntur V
GV
Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Pearse
Stuart J
SJ
Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.|School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Gopalakrishnan
Subramaniam
S
Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Ito
Osamu
O
Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Ishikawa
Takayuki
T
Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Kawano
Naoyoshi
N
Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Nakahara
Kazuhiko
K
Food Science & Technology Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Yoshihashi
Tadashi
T
Food Science & Technology Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Ono
Hiroshi
H
National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
Yoshida
Mitsuru
M
National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D019811:Hydroxylamine / Q000494:pharmacology; D015394:Molecular Structure; D009584:Nitrogen / Q000378:metabolism*; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D053147:Plant Exudates; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D011422:Propionates / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D045868:Sorghum / Q000737:chemistry / Q000378:metabolism*
D004791:Enzyme Inhibitors; D010636:Phenols; D053147:Plant Exudates; D011422:Propionates; C535177:methyl 3-(4-hydroxyphenyl)propionate; D019811:Hydroxylamine; D009584:Nitrogen