Transformation of sunflower (Helianthus annuus L.): a reliable protocol.

A reliable protocol for the transformation of cultivated sunflower (Helianthus annuus L.) has been established, based on microprojectile bombardment of half shoot apices in combination with Agrobacterium tumefaciens coculture. Transgenic shoots have been obtained from 5 inbred lines, although transformation efficiencies varied with the genotype. Plants expressing the transgenes could be recovered from up to 7% of the explants. A minority of plants was shown to be chimaeric for expression of ß-glucuronidase activity while most appeared to be uniformly transformed. Genetic segregation was 3∶1 for both ß-glucuronidase and neomycine phospho transferase in some plants, indicating that the respective mother plants were uniformly transformed. Integration of the foreign genes was also shown by Southern analysis.