Green factories: plastids for the production of foreign proteins at high levels

The soaring costs along with the increasing demand of recombinant proteins in different walks of life have fuelled the quest to find out alternate modes for their production, which are cheaper, safer and can deliver the modern safety standards. In this context, plants are emerging as an alternative production platform for foreign proteins. Chloroplasts - the green plastids with an in-built remarkable capacity to express foreign proteins at high levels offer several attractive features, which make plants an exceptionally useful system for low-cost production of high-value targets at large scale. Transformation of chloroplasts, therefore, holds a great potential to meet the challenges in the areas of food, feed and medicine posed by a population on the rise. Numerous developments have been made in the field, all of which set plastids to become a centrepoint of future plant engineering efforts. The present review briefly describes 'the state of the art' of the technology along with its salient features whilst highlighting the latest trends in the area of chloroplast transformation.