Ing. Klára Hoyerová, Ph.D., RNDr. Martin Kubeš, Ph.D., and doc. RNDr. Eva Zažímalová, CSc., from the Institute of Experimental Botany of The CAS took part in the newly published article of the prestigious journal Nature Plants. Their research focused on nitrogen – that is the essential building block of plant nutrition and when there is a lack of it, not only chlorophyll production slows but also the growth of the stem and leaves. Nitrogen arrives at the cells of the root from the soil solution in the form of nitrate, namely through the transceptor NRT1.1/NPF6.3. “This protein is incorporated into the plasma membrane and, in addition to the ability to transport nitrate, it independently sends signals to detect the presence of nitrate. Already this dual function itself is unique in and of itself, but the possibility of NRT1.1/NPF6.3 does not end there. In addition to transporting nitrate, it can transfer the important plant hormone auxin across the plasma membrane,” explains Ing. Klára Hoyerová, Ph.D.
According to the availability of nitrate in the soil, auxin then accumulates in the root ends and the roots extend. NRT1.1/NPF6.3 triggers a wide range of responses to the nitrate signal. “We have participated in the revelation of the mechanism by which NRT1.1/NPF6.3 ‘switches’ between the responses to nitrate. After the mutation of amino acid threonine 101, the protein is in the phosphorylated or non-phosphorylated form and only that phosphorylated mediates the effect of the nitrate on the growth of roots through auxin, whereas the non-phosphorylated form plays a role in triggering entirely different genes. If there is a substitution of the amino acid proline 492, the altered structure of NRT1.1/NPF6.3 no longer allows nitrate transport, but still mediates the nitrate signal, which again induces different responses in gene expression,” adds Ing. Klára Hoyerová, Ph.D. It has thus been shown that small changes on the level of the structure of this protein are responsible for various responses to nitrate.
5 Mar 2015
