SUPRESSION OF ENZYMATIC BROWNING IN POTATO PLANTS BY RNA INTERFERENCE

LLORENTE, BRIARDO E.; BRAVO ALMONACID, FERNANDO F.; TORRES, HECTOR N.; FLAWIÁ, MITHA M.; ALONSO, GUILLERMO D.

Pinamar, Argentina.

Congreso; X Congress of the Pan-American Association for Biochemistry and Molecular Biology (PABMB), XLI Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology (SAIB) and the XX Annual Meeting of the Argentine Society for Neurochemistry (SAN; 2005

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

Damage caused by post-harvest enzymatic browning is one of the main economic problems to potato producers and Food Industry. We have developed different transgenic potato plants which present Polyphenol oxidase (PPO) activity inhibition by using RNA interference technology. In order to silence PPO expression, sense and antisense gene fragments of 400 bp from the 5´ region of the potato pot32 gene and an 840 bp spliceable spacer were ligated into a binary vector pZP200-HYG under the control of a constitutive promoter to generate a recombinant plasmid pJAPI. This plasmid was subsequently transformed into potato (Solanum tuberosum) var. spunta via Agrobacterium tumefaciens mediated tuber transformation. Selection with hygromycine and PCR detection assays yielded over 30 different transgenic lines. RNA expression, PPO activity and phenotype were initially analyzed in 4 transgenic lines. We show that PPO mRNA levels and PPO activity correlate with the reduction in enzymatic browning in these lines and no detrimental side effects have been detected so far.  This suppression which eliminates sensitivity to bruising could prevent huge losses occurring during the harvest (over 20%) and help avoid the use of various additives during the processing of potato derived commercial products.