Biological nitrification inhibition by rice root exudates and its relationship with nitrogen‐use efficiency

Abstract

Microbial nitrification in soils is a major contributor to nitrogen (N) loss in agricultural systems. Some plants can secrete organic substances that act as biological nitrification inhibitors (BNIs), and a small number of BNIs have been identified and characterized. However, virtually no research has focused on the important food crop, rice (Oryza sativa). Here, 19 rice varieties were explored for BNI potential on the key nitrifying bacterium Nitrosomonas europaea. Exudates from both indica and japonica genotypes were found to possess strong BNI potential. Older seedlings had higher BNI abilities than younger ones; Zhongjiu25 (ZJ25) and Wuyunjing7 (WYJ7) were the most effective genotypes among indica and japonica varieties, respectively. A new nitrification inhibitor, 1,9-decanediol, was identified, shown to block the ammonia monooxygenase (AMO) pathway of ammonia oxidation and to possess an 80% effective dose (ED ) of 90 ng μl . Plant N-use efficiency (NUE) was determined using a N-labeling method. Correlation analyses indicated that both BNI abilities and 1,9-decanediol amounts of root exudates were positively correlated with plant ammonium-use efficiency and ammonium preference. These findings provide important new insights into the plant-bacterial interactions involved in the soil N cycle, and improve our understanding of the BNI capacity of rice in the context of NUE.

Nitrous oxide emission from agricultural soils

“…Some crops are able to produce nitrification inhibitors during a process called biological nitrification inhibition (BNI). This has been demonstrated in a tropical grass species, for rice (Sun et al, 2016), wheat (O'Sullivan et al, 2016, millet, peanut and sorghum (Subbarao et al, 2013;Li et al, 2018). It is possible to extract and use BNI substances from plants.…”

How belowground interactions contribute to the coexistence of mycorrhizal and non-mycorrhizal species in severely phosphorus-impoverished hyperdiverse ecosystems

“…The presence of suberin lamellae was detected by yellow-green fluorescence (white arrowheads); the presence of lignin was detected by orange-red staining (black arrowheads). Bars = 100 μm 2003; Oburger et al 2014;Pearse et al 2006;Sun et al 2016). There is good information on angiosperm species in specific families that do or do not produce an exodermis; the vast majority of angiosperms does produce an exodermis (Perumalla et al 1990).…”

Nitrogen Transformations Associated with N2O Emissions in Agricultural Soils

“…In further studies, it was found that some plant species synthesized important organic compounds and released these compounds into surrounding soils via roots [60]. These compounds were found being able to inhibit nitriication process, imposing similar Biological nitriication inhibitors generally including phenolic compounds, alkaloid, isothiocyanate and terpenoid [60,61]. For example, chemicals produced by Arbutus unedo, including phenolic compounds gallocatechin and catechin were able to decrease soil N 2 O emissions [62].…”