Molecular determination and genetic modification of flower colour in Lilium spp

Lily (genus Lilium, family Liliaceae) is one of the most important ornamental crops for the production of flower bulbs and cut flowers. Conventional breeding might be inefficient for introducing variation in flower colours in L. longiflorum due to hybrid sterility and deficiency of genetic resources in related, crossable species. An alternative is provided by the technology of genetic modification, but lily is among the monocot species that is recalcitrant to genetic transformation by A. tumefaciens and thus exhibits a low transformation efficiency (TE). There is a need to enhance TE in lily. Because lily transformation is proven to be difficult and time consuming, we developed and optimized a simple agroinfiltration method in order to monitor transient gene expression of anthocyanin structural genes and regulatory genes in lily tepals. In addition, we determined molecular mechanisms regulating flower colour in lilies by an expression analysis of anthocyanin biosynthesis-related genes during multiple flower developmental stages. As a result, DFR was found to be the main bottleneck for not having colour in L. longiflorum cv. ‘Lincoln’ and the Oriental hybrid cv. ‘Rialto’.  A follow up of this research should focus on a careful selection and characterization of a functional and suitable DFR gene copy from other lilies or another crop in order to produce novel flower colour in both cultivars.