Submitted to: Biomed Central (BMC) Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 20, 2012
Publication Date: March 20, 2012
Citation: Payyavula, R., Navarre, D.A., Kuhl, J., Pantoja, A., Kumar, S. 2012. Differential effects of environment on potato phenylpropanoid and carotenoid expression. Biomed Central (BMC) Plant Biology. 12:39. DOI: 0.1186/1471-2229-12-39. Interpretive Summary: The extent of environmental effects on tuber phytonutrients is unclear, as is whether environment significantly influences potato nutritional quality. Many plant phytonutrients are known to be influenced by environment, especially plant compounds that are antixoidants. If environment has a small or modest influence on tuber phytonutrients, then this is unlikely to have a large impact on nutritional quality. If environmental effects on potato phytonutrients are large, this could complicate constructing accurate nutritional databases and the attachment of health claims or nutritional label to foods. On the other hand, large differences would suggest that manipulating the signal transduction chains that transduce environmental signals could be used to enhance the nutritional value of potatoes. We grew potatoes in diverse locations from the Artic circle to Florida and measured concentrations of ~40 tuber phytonutrients and expression of 20 genes to better understand environmental effects. We found over a two-fold difference in some phytonutrients and the magnitude of the differences suggest environment can meaningfully influence the nutritonal value of potatoes. This work also suggests environment could be manipulated to grow a more nutritous crop.
Technical Abstract: The extent of environmental effects on tuber phytonutrients is unclear, as is whether environment significantly influences potato nutritional quality. Potatoes grown in environmentally diverse locations in North America (Alaska, Texas and Florida) were profiled for over forty tuber phenylpropanoids and carotenoids, and expression of twenty structural genes was measured by qPCR. Total phenolics and chlorogenic acid levels were higher in samples from the northern latitudes, as was expression of phenylpropanoid genes including phenylalanine ammonia lyase (PAL), which had over a ten-fold difference in relative abundance. Anthocyanins were more abundant in Alaskan samples and correlated with flavonoid genes including DFR, UFGT and F3H. The most abundant anthocyanin was petunidin-3-coum-rutinoside-5-glu, which ranged from 4.7 mg g-1 in Alaska to 2.3 mg g-1 in Texas. Smaller differences in total carotenoids occurred and did not correlate with latitude. However, marked differences occurred in individual carotenoids, with over a ten-fold range in some carotenoids between locations. Violaxanthin, lutein or zeaxanthin were the predominant carotenoids in tubers from Alaska, Texas and Florida respectively. Good correlation occurred between most phenylpropanoid metabolites and transcripts, but poor correlation between carotenoid transcripts and metabolites. The sizeable differences suggest environment can meaningfully influence potato nutritional value.’