Genetic Engineering in Safflower (Carthamus tinctorius L.): Retrospect and Prospect

Safflower (Carthamus tinctorius L., Asteraceae) is an important edible oilseed crop. Because of the distinct seed oil profile, high α-tocopherol content, utilization as a leafy vegetable and useful petal pigments, it has special value among oilseed crops and is of much scientific interest. Recently, safflower has been improved for agronomical, nutritional and other traits with the introduction of specific genes from safflower and also other sources. The prerequisite for successful transformation is development of an in vitro propagation protocol, transformation method and gene of interest. Variation exists in regeneration frequency via organogenesis or somatic embryogenesis in different genotypes of safflower. Therefore, standardization of regeneration protocol is necessary for each genotype before gene transformation. Among different explants, cotyledons and apical shoot tips were found suitable for transformation and shoot regeneration. Agrobacterium-mediated transformation is the successful method for gene transfers in safflower. So far using this method, transformation has been achieved for the enhancement of γ-linolenic acid (GLA), α-linolenic acid (ALA), oleic acid, bioactive peptide, bioactive flavonoid and resistance to fungal pathogen Alternaria carthami. The commercial cultivation of genetically modified (GM) safflower is in progress in Australia, Canada and the USA. However, there is scope for improving the frequency of plant regeneration and genetic transformation. The present chapter describes the recent developments in genetic transformation and improvement of safflower.