36th International Carrot Conference Abstract

Elucidating the genetic basis underlying anthocyanin pigmentation in carrot

Pablo F. Cavagnaro^1,2, Massimo Iorizzo¹, Mehtap Yildiz³, Douglas Senalik^1,4, Joshua Parsons¹, David K. Willis^4,5, Allen Van Daynze⁶, Philipp W. Simon^1,4*

¹ Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI 53706, USA
2 CONICET, Facultad de Ciencias Agrarias – Universidad Nacional de Cuyo, and INTA E.E.A. La Consulta, Ex Ruta 40. km 96, La Consulta CC 8, Mendoza (5567), Argentina.
³ Department of Agricultural Biotechnology, Faculty of Agriculture, Yuzuncu Yil University, 65080, Van, Turkey
⁴ USDA-Agricultural Research Service, Vegetable Crops Unit, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI 53706, USA
⁵ Department of Plant Pathology, University of Wisconsin-Madison, 1575 Linden Drive, Madison WI 53706, USA
⁶ Seed Biotechnology Center, University of California, Davis, CA, 95616.
^* Corresponding author: email: Philipp.Simon@ars.usda.gov

Anthocyanins play a central role in the development of color, flavor and health attributes of numerous plant species. To date, research on anthocyanins genetics and biochemistry has mainly focused on anthocyanin-containing fruits, leaves and flowers of crop or model species. However, little is known about root anthocyanins. Purple or “black” carrots accumulate relatively large quantities of anthocyanins in their roots composed entirely of cyanidin glycosides with a predominance of acylated forms over non-acylated anthocyanins. This study investigated the genetic basis of anthocyanin accumulation in an F₂ mapping population (N=450) derived from a cross between a purple and a non-purple (orange) rooted carrot. Root purple pigmentation segregated consistent with a two gene model for an F₂, whereas leaves (petiole) purple pigmentation fitted a single dominant gene model. HPLC analysis on a subset of the F₂ (N=184) revealed significant variation for all five anthocyanin pigments previously reported in carrot. A high resolution single nucleotide polymorphism (SNP) based map was constructed with this set of samples. Significant QTL were found for all anthocyanin pigments. QTL mapping revealed two regions in chromosome 3 with co-localized QTL for the different anthocyanin compounds. Leaf purple pigmentation, scored visually by the presence-absence of purple in the petioles- mapped to one of the two regions with QTL for root anthocyanins, suggesting that this QTL may also control leaf pigmentation. Expression analysis of candidate genes that co-localized with the root anthocyanin QTL revealed differential expression -in purple versus non-purple rooted carrots- for 5 genes involved in anthocyanin biosynthesis and accumulation. Comparative mapping with other purple segregating populations indicated that the genetic factors controlling purple pigmentation in this F₂ are different than those reported previously in other genetic backgrounds. These results will contribute to our understanding of the genetic control underlying anthocyanin pigmentation in carrot and –perhaps- other species.

Last updated Wednesday, 07-Aug-2013 12:19:19 CDT