Discovery of biological nitrification inhibitors in maize roots
Nitrogen (N) fertilizer is an essential component for growing most crop plants. However, almost half of the applied N fertilizer is lost from soil as nitrate (NO3–, a water pollutant) and as nitrous oxide (N2O, a greenhouse gas) by two microbial metabolic processes: nitrification and denitrification, respectively. To control agronomic N losses, biological nitrification inhibition (BNI) is a promising strategy. BNI is an ecological phenomenon by which certain plants release bioactive natural products that can suppress nitrifying soil microbes. Our objective in this research is the identification of hydrophobic BNI compounds released from maize roots.
In the search for BNI compounds from the surface extract of maize roots, a new highly BNI active compound was discovered, together with a highly active compound. In addition, two BNI active compounds were identified from the root extract of maize (Fig. 1). The compound with the strongest BNI activity (the ability to suppress nitrification by nitrifying bacteria) was named “zeanone” because it was the first BNI compound to be discovered in nature. The four compounds, including the newly discovered zeanone, were found to have an activity equivalent to 45% of the total BNI activity of maize roots (Table 1). Based on the obtained results, a BNI mechanism in maize is proposed (Fig. 2).
The results of this research are expected to open the way for the construction of eco-friendly agricultural production systems that utilize the BNI-producing ability (BNI capacity) of maize.
Table 1. Quantity of BNI compounds in maize roots
Fig. 1. Structure and BNI activity of BNI compounds
Fig. 2. Proposed BNI mechanism in maize
Figures and table reprinted/modified with permission from Otaka et al. (2021).
- Research project
- Program name
- Term of research
- Responsible researcher
Otaka Junnosuke ( Biological Resources and Post-harvest Division )
Subbarao Guntur Venkata ( Crop, Livestock and Environment Division )
Hiroshi Ono ( National Agriculture and Food Research Organization (NARO) )
Yoshihashi Tadashi ( Crop, Livestock and Environment Division )
- Publication, etc.
Otaka et al. (2021) Biol Fertil Soils 58: 251-264https://doi.org/10.1007/s00374-021-01577-x
- Japanese PDF
- English PDF
- Poster PDF
＊ Affiliation at the time of implementation of the study.