A coordinate expression of structural genes determine the production of phenolic acids and flavonoids in tubers from Andean potato varieties

VALIÑAS MA; LANTERI L; TEN HAVE A; ANDREU AB

Mar del Plata

Congreso; XV Congreso Latinoamericano de Fisiología Vegetal ? XXX Reunión Argentina de Fisiología Vegetal; 2014

UNMDP

Chlorogenic acid (CGA) is the major phenolic acid in potato tubers. Anthocyanins and flavan-3-ols are flavonoids, the former being present in pigmented tissues. The synthesis of CGA involves two enzymes HQT and HCT, whereas LCR or ANR result in the production of flavan-3-ols. The synthesis of anthocyanins requires consecutive steps catalyzed by CHS, CHI, F3H, DFR, ANS and 3UGT. In order to gain insight into how the metabolic network works, we studied the expression levels of structural genes by RT-qPCR and the metabolite levels by HPLC-DAD in skin and flesh of tubers from four Andean varieties. Results show that both metabolites and transcripts were, in general, higher in skin than in flesh. CGA levels correlated well with HCT rather than HQT. Despite the fact that flavan-3-ols were present, we could not detect LCR while ANR show similar levels between tissues and varieties. Therefore the synthesis of flavan-3-ols would imply an ANR with epimerase activity. There was a good correspondence between the anthocyanin content and transcript levels of CHS, CHI, F3H, DFR and ANS. Data support the hypothesis that the synthesis of phenolic acids and flavonoids is regulated at transcriptional level in a coordinate manner.