Investigation of the role of transcription factor maize Lc in pigmentation pathways in potato (Solanum tuberosum L.)

Abstract

Potato is an important target crop for biotechnological applications and is a valuable model system for studying the regulation of the flavonoid biosynthetic pathway. Genetic transformation of 22 potato (Solanum tuberosum) cultivars was carried out using leaf discs as explants for Agrobacterium tumefaciens-mediated gene transfer. The explants were co-cultivated with Agrobacterium strain LBA4404 harbouring a binary vector with the maize anthocyanin regulatory gene Lc under the control of the cauliflower mosaic virus 35S promoter with a npt II gene conferring kanamycin resistance as a selectable marker. Observations of the callus cultures show that Lc appears to have a functional role in the pigmentation pathway in ten of the 22 potato cultivars with varied degree of anthocyanin enhancement. Subsequently, the cultivars 'Iwa', 'Desiree', 'Red Rascal', 'Purple Passion', 'Urenika' and '2765-5' were selected to study the transcriptional expression of Lc in foliage and harvested tubers. Transgenic status of plants was confirmed by PCR and transgenic plants that exhibited the expression of the Lc transgene was established using RT-PCR, evident in the leaves and harvested tubers of transgenic potato plants accumulating anthocyanins. This investigation illustrates the utility of an anthocyanin regulatory gene for the genetic manipulation of colour in potato plants. It also supports the premise that Lc can be used as a powerful non-destructive cell autonomous visual marker in a wide variety of plants.