Submitted to: Journal of Sugarbeet Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 15, 2007
Publication Date: June 20, 2007
Citation: Kuykendall, L.D., Murphy, T.S., Shao, J.Y., Mcgrath, J.M. 2007. Nucleotide Sequence Analyses of a Sugar Beet Genomic NPR1-class Disease Resistance Gene. Journal of Sugarbeet Research. 44:35-49. Interpretive Summary: Sugar beets supply about one half of US domestic sugar. The efficiency and profitability of crop production is significantly limited by diseases. In order to grow healthy crops without the use of harmful chemicals, new knowledge of the genetic mechanisms plants employ to resist attack by microbes is needed. In this sugar beet research, a gene which may play a central role in disease resistance was identified, isolated and analyzed as a first step toward improving disease resistance. Plant molecular geneticists can use these data to improve disease resistance in sugar beet.
Technical Abstract: Disease resistance in Arabidopsis thaliana is centrally controlled by the NPR1 gene that modulates multiple disease response pathways. A homolog of NPR1 was isolated from Beta vulgaris as a first step in deducing the potentially similarly important role of this gene for sugar beet disease resistance. Significantly, this homolog was isolated from a Bacterial Artificial Chromosome library of sugar beet, allowing characterization of a sugar beet gene in its native genomic state and allowing the first direct sequence comparison of genomic DNA sequence between an important model organism and sugar beet. Most structural and nucleotide sequence features of the Arabidopsis NPR1 gene were similar with the isolated beet NPR1 homolog, including utilization of an unusual transcription start site motif, similarly positioned BTB/POZ and ankyrin repeat domains, and the coding sequence interrupted by three similarly positioned introns. In contrast, the length of the sugar beet NPR1 homolog was three-fold greater than that of Arabidopsis, and most of the size difference between beet and Arabidopsis occurred in non-coding DNA sequences such as introns. The predicted protein product of the sugar beet NPR1-homolog has 100% nucleotide sequence identity with the full-length Beta vulgaris NPR1 cDNA sequence AY640381.