Investigation of the interconversion of L­arabinose and D­xylose as regulated by candidate pathway genes in Beta vulgaris using comparative genomics

Authors: SHI, ARTHUR - Michigan State University; GALEWSKI, PAUL - Michigan State University; McGrath, Jon

Submitted to: Annual Beet Sugar Development Foundation Research Report
Publication Type: Research Notes
Publication Acceptance Date: 4/15/2015
Publication Date: 6/1/2015
Citation: Shi, A., Galewski, P., McGrath, J.M. 2015. Investigation of the interconversion of L­arabinose and D­xylose as regulated by candidate pathway genes in Beta vulgaris using comparative genomics. [CD-ROM] 2014 Annual Beet Sugar Development Foundation Research Report. Denver, Colorado: Beet Sugar Development Foundation.

Interpretive Summary:

Technical Abstract: Arabinose and xylose occur in hemicellulose, a group of polysaccharides present in plant cell walls in all terrestrial plants. Xylose is an aldopentose sugar with uses as a chemical feedstock, and this study sought to explore the possibility of using sugar beet as an industrial source of xylose, which is present at high proportions in stems and seeds of sugar beet. Biochemical evidence suggests that xylose is converted to arabinose through the action of the enzyme UDP­D­Xylose 4­epimerase as a result of transcription and translation of the Arabidopsis gene mur4. Triplicate samples showed similar results of amplification of the beet homolog of mur4 in stem and seed tissues. Thus, with increasing development of floral tissues, expression of mur4 increased, suggesting that reduction in the level of this transcriptionally-regulated enzyme in older tissue prevented conversion of xylose to arabinose, and thus xylose proportions increased during development. These reults suggest that sugar beet roots may be modified by inhibiting the action of UDP­D­Xylose 4­epimerase in roots, thus increasing the supply and availability of xylose as a chemical feedstock.