Expression of afibrobacter succinogenes 1,3-1,4-β-glucanase in Potato (Solanum tuberosum)

The potential development of potato (Solanum tuberosum) as a low-cost eukaryotic system for the production of a commercially valuable enzyme feed supplement was examined. AFibrobacter succinogenes 1,3-1,4-β-glucanase 1,3-1,4-β-D-glucan 4-glucanohydro-lase] gene under the control of the constitutive cauliflower mosaic virus 35S promoter was transferred into the potato cultivar, Desiree. The presence of the β-glucanase cDNA in the plant genome of independent transgenic potato lines was confirmed by PCR and Southern analysis. Northern analysis identified the presence of the β-glucanase mRNA in the leaf tissue of transgenic plants. Furthermore, western analysis showedF. succinogenes β-glucanase accumulations of 0.1% and 0.05% of total soluble protein in the leaves and tubers, respectively. Specific activities of the enzyme in leaves (1693 units mg^-1 β-glucanase) and tubers (2978 units mg^-1 β-glucanase) were comparable to that previously reported for the enzyme produced in bacteria. Lyophilization of leaves had no effect on the specific activity of the β-glucanase, and only marginally influenced the specific activity of the enzyme expressed in tubers. Relative to the control line (cv. Desiree), tuber yields were significantly reduced by 28%-72% in all lines expressing theF. succinogenes β-glucanase, and microscopy showed that expression of the β-glucanase caused changes in cell wall structure. Results of this study demonstrate that a 1,3-1,4-β-glucanase can be expressed in potato tissues, and that potato plants have the potential to be used for the commercial production of heterologous enzymes.