Nitric oxide-fixation by non-symbiotic haemoglobin proteins in plants

Nitrogen oxides (NOx; mainly NO and NO2) are naturally present in the atmosphere as part of the Earth's nitrogen cycle, and have a variety of natural sources. We demonstrated a NO-fixing capability of non-symbiotic hemoglobin proteins allowing a channeling of atmospheric NO into the plant N metabolism. This pathway is probably important under conditions with limited N supply via the soil. Moreover, the plant-based NO-fixation lowers the concentration of atmospheric NOx and in this context plants have a beneficial effect on air quality and human health.

We are interested in the positive effects of atmospheric NO on plant growth and development and how the NO-fixing capability of plants can be used to improve air quality.



Schematic of the proposed NO-fixation pathway. NO is oxidized enzymatically to nitrate by oxy-non-symbiotic hemoglobin(1). In a two-step process, nitrate is reduced to ammonia by nitrate reductase(2) and nitrite reductase(3). (Kuruthukulangarakoola et al., 2017)