Chloroplast genetic engineering to improve agronomic traits.

Major crop losses occur annually as a result of biotic and abiotic stresses. The ability to hyperexpress foreign proteins, single-step multigene engineering, lack of positive effect and gene silencing, vector sequences and pleiotropic effects have resulted in several hundred-fold more tolerance to the environmental stresses via chloroplast genetic engineering than nuclear genetic engineering. Maternal inheritance of chloroplast expressed transgenes renders the technology environmentally safe and promotes public acceptance. This review provides protocols for engineering agronomic traits like insect, herbicide and disease resistance; salt and drought tolerance; and phyto-remediation via chloroplast genome.