Molecular breeding of a blue Kalanchoë

Danish title: Molekylær forædling af en blå kalanchoë

 

Kalanchoë blossfeldiana is a major pot plant in Denmark and Holland. The aim of this research project is to design a blue Kalanchoë plant by molecular breeding. Kalanchoë blossfeldiana varieties with orange, pink, red, and magenta flowers were found to contain 3,5-O-beta-D-diglucosides of pelargonidin, cyanidin, peonidin, delphinidin, petunidin and malvidin. Pink, red and magenta varieties contained relatively high amounts of quercitin based flavonoids. Four distinct flavonoids were identified, namely quercitin 3-O-beta-D-glucoside and three that were quercitin 3-O-alpha-L-rhamnoside based, with either glucose, xylose or arabinose attached to position 2 of the rhamnose. In addition, the presence of at least three kaempferol based diglycosides was suggested from LC-MS analyses. Orange varieties contained very low amounts of flavonoid co-pigments and of delphinidin derivatives. The flower extracts of the varieties “Diva” (magenta) and “Molly” (red) had identical anthocyanidin ratios but differed significantly in flavonol content. The magenta variety contained four times as much quercitin relative to anthocyanidin as the red variety. This difference was mainly due to a larger content of quercitin 3-O-(2”-O-beta-D-glucopyranosyl-alpha-L-rhamnosylpyranoside).

An efficient Agrobacterium based transformation method for Kalanchoë has been developed and based on pigment and co-pigment analyses, five different strategies focusing on increasing delphinidin and co-pigment content are currently being tested including down-regulation of flavonoid 3´-hydroxylase using RNAi technology and introduction of flavone synthase II from other plant species.

 

Researchers involved: Allan Holm Nielsen, Søren Bak, Kirsten Jørgensen, Birger Lindberg Møller

 

Financial support: Gartneriet Poul Erland Nielsen, Kerteminde, KVL PhD stipend