Nitrate: Nutrient and Signaling Molecule

Plant growth depends among other things, on the amount of nutrients in the soil. Studies show that growth of well formed roots and shoots are indicative of soil fertility. A group of international scientists led by Eva Benkova of the Flanders Institute for Biotechnology in Belgium and partners at the Plant Biochemistry and Molecular Physiology (PBMP) Department in Montpellier, France, Institute of Experimental Botany at the Academy of Sciences of the Czech Republic and the Umeå Plant Science Centre at the Swedish University of Agricultural Sciences studied this phenomenon further focusing on the nitrogen fertilitiy of the soil and the growth of lateral roots.

Nitrogen in the form of nitrate provides nutrients for plant growth and development. In addition, the research team found that nitrate also acts as a signaling molecule in the development of lateral roots. NRT1.1 protein was previously reported to be responsible for taking up nitrate from the soil and contributes to sensing and nitrate signalling. The team in France discovered a connection between NRT1.1 and the major plant hormone auxin, which among other things, is heavily involved in root development.

"We propose that NRT1.1 represses lateral root growth at low nitrate availability by promoting auxin transport out of lateral root tips and towards the base of the root. Thus, high nitrate availability stimulates lateral root growth by inhibiting NRT1.1-dependent auxin transport and allowing auxin accumulation in root tips," concluded Dr. Gojon of PBMP. "This defines a mechanism connecting nutrient and hormone signalling during organ development."

For details, see the news article at http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&SESSION=&RCN=32211