Soft-rot Resistance of Coloured Potato Cultivars (Solanum tuberosum L.): The Role of Anthocyanins

Abstract

Coloured potatoes (Solanum tuberosum L.) rich in anthocyanins are gaining increasing interest on the markets, mainly due to beneficial health effects. Potato varieties containing colour pigments are therefore utilized more and more in actual breeding programmes. In this study, 10 purple-fleshed potato cultivars were compared in their resistance to soft rot caused by Pectobacterium carotovorum (Pc) with 10 white/yellow-fleshed potato cultivars. The results revealed that coloured potato cultivars exhibited on average better resistance to soft rot than white/yellowfleshed potato cultivars. On tuber halves of purple-fleshed cultivars, the extent of rotting caused by Pc was on average 28.6% lower than on white/yellow-fleshed cultivars. The greater resistance of coloured potatoes coincided with the presence of anthocyanins, higher concentrations of soluble phenols and elevated polyphenol oxidase activity in tuber tissue. These three components were significantly correlated with the extent of rotting caused by Pc. However, coloured and white/yellow-fleshed cultivars were not very different in phenylalanine ammonia-lyase and peroxidase activity. There were also no significant differences in concentrations of dry matter, starch, crude protein and glycoalkaloids. Key findings reveal that total soluble phenols and anthocyanins contributed crucially to resistance expression in tuber tissue of coloured potato cultivars.

Special quality traits of coloured potato breeding clones: Anthocyanins, soluble phenols and antioxidant capacity

“…During field trials, six of the coloured clones reached an anthocyanin content of > 1.00 g kg −1 fw (Table 3c)—clone St 89 403‐99 achieved a value of > 1.70 g kg −1 fw. These coloured breeding clones far exceeded the anthocyanin levels reported for other purple fleshed potato clones22 and cultivars 23. The three purple fleshed cultivars involved in the test series of 2005 had on average less anthocyanins in skin, flesh and whole tubers than the coloured breeding clones (Table 3).…”

“…In addition, they are precursors in the biosynthesis of lignin and suberin, both decisive constituents of physical barriers that can block the spread of plant pathogens 41. Accordingly, the increase in phenols by wounding is important with respect to resistance expression in tuber tissue 23…”

Antioxidant activity of potatoes (Solanum tuberosum L.) and anthocyanin content, its biosynthesis and physiological role

“…Кроме того, наличие антоцианов может уменьшить восприимчивость к заражению насекомыми и патогенами. Клубни картофеля с высоким содержанием антоцианов на 28% более устойчивы к поражению мокрой гнилью [57]. Растения с высоким содержанием антоцианов в листьях демонстрируют большую устойчивость к тепловому стрес-су и более быстрое восстановление после окислительного стресса, вызванного механическим повреждением [56].…”

Potato soil-borne diseases. A review

“…Verticillium dahliae and V. albo-atrum Wanner (2007) because cultivars producing anthocyanins can provide better resistance to soft rot or other diseases compared to white/yellow flesh cultivars (Wegener and Jansen 2007). Cultivars resistant to several diseases were obtained, but simultaneous resistance to all pathogens is very difficult to achieve.…”