Organelle DNA contents and starch accumulation in potato tubers
Starch contents were found to be positively correlated with organelle/nuclear DNA ratios, suggesting that these ratios are involved in starch accumulation and may serve as a target trait in genetic engineering and a biomarker in breeding for improving the dry matter and starch production in potato.
Starch is the main dry matter component of various staple food crops, including potato. Starch synthesis and accumulation is in plastids, uses sugar, consumes cellular energy, and requires active expression of starch synthesis genes. We hypothesized that the plastid/nuclear DNA ratios and mitochondrial/nuclear DNA ratios are involved in this accumulation. We analyzed the dry mater, starch, plastid DNA, mitochondrial DNA, and nuclear DNA in tuber stem ends and tuber bud ends in two potato cultivars and verified the results using whole tubers in nine potato cultivars. Dry matter contents (DMC) and organelle/nuclear DNA ratios increased rapidly during tuber bulking. DMC and starch contents were greater at the tuber stem ends than at the tuber bud ends. Both the comparisons between tuber ends and among whole tubers indicated that DMC and starch contents were positively correlated with both plastid/nuclear DNA ratios and mitochondrial/nuclear DNA ratios. The results suggest that pt/nuc and mt/nuc DNA ratios are important and may serve as a biomarker in selection, genetic engineering, and cytoplasm manipulation, for dry matter and starch accumulation in potato.
We thank the China Scholarship Council for its support to GDZ, the greenhouse management team of the Fredericton Research and Development Centre of Agriculture and Agri-Food Canada for the support in growing the potato plants. The research was supported by A-base funding from Agriculture and Agri-Food Canada to XQL.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Barclay G, Scott P (1997) Potato varieties in Canada. New Brunswick Department of Agriculture and Rural Development, FrederictonGoogle Scholar
- Centeno DC, Osorio S, Nunes-Nesi A, Bertolo AL, Carneiro RT, Araújo WL, Steinhauser M-C, Michalska J, Rohrmann J, Geigenberger P (2011) Malate plays a crucial role in starch metabolism, ripening, and soluble solid content of tomato fruit and affects postharvest softening. Plant Cell 23:162–184CrossRefGoogle Scholar
- Liu B, Zhang G, Murphy A, De Koeyer D, Tai H, Bizimungu B, Si H, Li XQ (2016) Differences between the bud end and stem end of potatoes in dry matter content, starch granule size, and carbohydrate metabolic gene expression at the growing and sprouting stages. J Agric Food Chem 64:1176–1184CrossRefGoogle Scholar
- Shinozaki K, Ohme M, Tanaka M, Wakasugi T, Hayshida N, Matsubayasha T, Zaita N, Chunwongse J, Obokata J, Yamaguchi-Shinozaki K, Ohto C, Torazawa K, Meng BY, Sugita M, Deno H, Kamogashira T, Yamada K, Kusuda J, Takaiwa F, Kata A, Tohdoh N, Shimada H, Sugiura M (1986) The complete nucleotide sequence of the tobacco chloroplast genome. Plant Mol Biol Rep 4:111–148CrossRefGoogle Scholar
- Szecowka M, Osorio S, Obata T, Araújo WL, Rohrmann J, Nunes-Nesi A, Fernie AR (2012) Decreasing the mitochondrial synthesis of malate in potato tubers does not affect plastidial starch synthesis, suggesting that the physiological regulation of ADPglucose pyrophosphorylase is context dependent. Plant Physiol 160:2227–2238CrossRefGoogle Scholar