Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2005
Publication Date: 7/31/2005
Citation: Sandrock, D., Azarenko, A., Martin, R.C., Bassil, N.V. 2005. Expression of the NRT1 gene in Cornus and Rhododendron. Abstract. HortScience. 40(4):271. p.1020. Interpretive Summary: Nitrogen is an important nutrient that is taken up through the root system of the plant. The purpose of this study was to determine if there are species differences in the expression of proteins that transport nitrogen into the plant during low nitrogen availability. Preliminary results indicate there are differences between species. This method could be used to examine when these proteins are expressed during the year and could be useful for determining optimal nitrogen fertilization schedules.
Technical Abstract: The NRT1 gene family encodes transport proteins with dual or low affinity for nitrate. The objectives of this experiment were to develop a system that could be used to compare the expression of the NRT1 genes between species. This was accomplished by comparing sequences of NRT1 homologues from various species and designing degenerate primers in regions of high homology. These primers were used to amplify a region of the NRT1 gene from species of interest. A 635 bp PCR product was amplified from each species using the MD2-1 (5’ ATGTTACCAAYWTGGGCMAC-3’) and MD2-2 (5’-GCCAMWARCCARTAGAAAT-3’) primers. The PCR products were cloned and sequenced. At the nucleotide level, Cornus sericea L. ‘Kelseyi’ and Rhododendron L. ‘Unique’ were 79.52 % identical. Species specific primers were designed and used for RT-PCR to compare NRT1 expression in roots of hydroponically grown C. sericea, C. sericea ‘Kelseyi’ and Rhododendron ‘Unique’. The relative levels of NRT1 expression, normalized using 18S rRNA as a standard, were approximately 3.2 to 1.7 to 1.0 for C. sericea, C. sericea ‘Kelseyi’ and Rhododendron ‘Unique’, respectively. This approach may eventually be used to examine nitrate uptake potential in different taxa of plants at different times during the growing season.