Nitrogen Input Alters Root Exudate Profiles and Nitrification Inhibition in Teosinte and Maize.

Area of Science:

• Agricultural Science
• Plant Biology
• Soil Science

Background:

• Teosinte (Zea mays subsp. mexicana) is a potential source of biological nitrification inhibition (BNI).
• The impact of nitrogen (N) inputs on teosinte's root exudate chemistry and nitrification processes is not well understood.

Purpose of the Study:

• To investigate how nitrogen availability influences teosinte's root exudate composition.
• To assess the effect of these exudates on nitrification processes.
• To identify specific compounds responsible for BNI in teosinte.

Main Methods:

• Comparative study of teosinte and maize cultivars under varying nitrogen conditions.
• Non-targeted metabolomics of root exudates.
• Quantitative PCR (qPCR) of rhizosphere amoA genes.
• Pure-culture assays with Nitrosomonas europaea.

Main Results:

• Nitrogen fertilization increased root exudation in teosinte, enriching amino and phenolic acids (histidine, glutamic acid, ferulic acid, vanillic acid).
• Teosinte exudates from N-fed plants significantly inhibited ammonia oxidation by N. europaea (~63%).
• Histidine, vanillic acid, and ferulic acid were identified as potential BNI compounds, possibly acting via copper chelation and phenolic interference.

Conclusions:

• Nitrogen availability alters teosinte's exudate profile, enhancing its nitrification suppression capabilities.
• Specific amino and phenolic acids in teosinte exudates contribute to biological nitrification inhibition.
• Harnessing these traits could improve nitrogen management and nitrogen-use efficiency in maize-based agriculture.