Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 28, 2012
Publication Date: August 14, 2012
Citation: Bethke, P.C., Wiberley-Bradford, A.E., Jiang, J. 2012. Long-term storage of low-invertase Katahdin at different temperature set points [abstract]. Potato Association of America Proceedings. Paper No. 057. Technical Abstract: Successful storage of processing potatoes balances the risk of crop loss caused by pathogen-dependent spoilage with the need to maintain the low tuber reducing sugar contents that are required to produce light-colored fried products. Potato varieties with very low expression of the vacuolar acid invertase gene VInv have the potential to reduce storage risk by allowing for storage at temperatures that slow pathogen activity while retaining acceptable color. Research was conducted with transgenic lines of Katahdin in which VInv expression was strongly suppressed using an RNA-interference construct. Tubers were stored at 3-9°C with the goal of determining the temperature sensitivity of silenced lines relative to control lines. Biochemical and molecular analyses were used to identify differences between suppressed lines and controls and further our understanding of sugar regulation in potato tubers. Chips with acceptable color were produced from silenced lines stored at 7-9oC until mid-May, but not at 3-5°C. Reducing sugar contents in silenced and control lines mirrored chip color. Sucrose contents in silenced lines were higher than in controls. Unlike control tubers, stem-end sucrose was higher than bud-end sucrose in suppressed lines. Few differences in gene expression between controls and suppressed lines were observed. The mRNA for VInv was less abundant and that for sucrose synthase was more abundant in tubers of suppressed lines than in controls; the latter might reflect a response to altered tuber sugar contents. Sucrose synthase activities at the bud and stem ends of tubers, however, were similar in WT and suppressed lines. Taken together, these data confirm the potential for long-term storage of potato tubers with high suppression of VInv.