Improvement of plastid transformation efficiency in potato by using vectors with homologous flanking sequences.

Low transformation frequencies limit the use of plastid transformation in potato and other crops. Hence, a breakthrough in chloroplast genetic engineering of agronomically important species is a highly desirable goal. We succeeded in achieving potato transformation efficiency up to one shoot every bombardment using a modified regeneration procedure and novel vectors containing potato flanking sequences for transgene integration by homologous recombination in the Large Single Copy region of the plastome. Vector delivery was performed by the biolistic approach. Such efficiency corresponds to 15-18-fold improvement compared to previous results obtained in potato with a progenitor vector of that used in our study, and is comparable to that usually achieved with tobacco. The results obtained represent a significant advancement towards the implementation of the plastid transformation technology in potato breeding and biotechnology.