Development of a direct transformation method by GFP screening and in vitro whole plant regeneration of Capsicum frutescens L.

Abstract

Background Capsicum is a genus of important spice crop that belongs to the chili lineage. However, many Capsicum species (family Solanaceae) are known to be recalcitrant to genetic transformation and in vitro regeneration, thus hampering the effort in using Capsicum species for detailed biological investigation. In this study, we have developed an optimized protocol for the direct transformation of Capsicum frutescens L. cv. Hot Lava via a biolistic particle delivery system. In addition, in vitro whole plant regeneration from the hypocotyl explants of C. frutescens was established. Results In this biolistic system study, explant target distance, bombardment helium (He) pressure and the size of microcarrier were the key parameters to be investigated. The optimized parameters based on screening of GFP expression were determined to be 6 cm target distance, 1350 psi of helium pressure and 1.6 μm of gold particle (microcarrier) size. The greatest number of shoots were obtained from hypocotyl as explant using Murashige and Skoog medium supplemented with 5.0 mg/L BAP and 0.1 mg/L NAA. An average of 5 shoots per explant were formed. Out of which, one shoot managed to form root and developed into whole plant. Conclusions We have obtained an optimized protocol for the biolistic transformation of chili and in vitro regeneration of chili plantlets. The establishment of the protocols will provide a platform for molecular breeding and biological studies of the chili plants.