World's First Discovery of a Biological Nitrification Inhibitor in Maize Roots
― First Step to Reducing Nitrogen Fertilizer Application and Making the Earth Healthier ―

A joint research group led by Dr. OTAKA Junnosuke, Dr. SUBBARAO Guntur and Dr. YOSHIHASHI Tadashi of JIRCAS, and Dr. ONO Hiroshi of the National Agriculture and Food Research Organization (NARO), has succeeded for the first time in identifying biological nitrification inhibition (BNI) compounds produced in maize roots. The results of this research are expected to pave the way for the construction of earth-friendly agricultural production systems that utilize the BNI-producing ability (BNI capacity) of maize. In modern agriculture, large amounts of industrially produced ammonia nitrogen fertilizer are applied to farmland and converted (nitrified) by soil bacteria, causing various problems caused by nitrogen loss, such as greenhouse gas emissions and water pollution.

JIRCAS aims to reduce nitrogen loss from agricultural lands utilizing the BNI effect of compounds produced in the roots of crops. The research group conducted a search for BNI compounds from the surface extract of maize roots and succeeded in discovering one new highly active compound, and also identified one highly active compound and two active compounds. 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. Enhancing the BNI capacity of maize, the most widely produced field crop in the world, based on the BNI compounds obtained in this study will reduce nitrogen fertilizer loss and environmental pollution, and improve the global nitrogen cycle.

The results of this research were published in the online edition of the scientific journal Biology and Fertility of Soils on June 17 (Japan time, June 18).

Authors

J Otaka, GV Subbarao, H Ono, T Yoshihashi

Title

Biological nitrification inhibition in maize — Isolation and identification of hydrophobic inhibitors from root exudates

Journal

Biology and Fertility of Soils
DOI: https://doi.org/10.1007/s00374-021-01577-x

JIRCAS President : KOYAMA Osamu
Program Director : HAYASHI Keiichi
Principal Investigators : 
OTAKA Junnosuke (Biological Resources and Post-harvest Division)
　　　YOSHIHASHI Tadashi (Biological Resources and Post-harvest Division)
　　　SUBBARAO Guntur (Crop, Livestock and Environment Division)
　　　ONO Hiroshi (Advanced Analysis Center, NARO)
Press Coordinator：OMORI Keisuke (Head, Information and Public Relations Office)
E-mail：koho-jircas@ml.affrc.go.jp