Expression of complete metabolic pathways in transgenic plants

Abstract

Plant genetic engineering emerged as a methodology to introduce only few transgenes into the plant genome. Following fast-paced developments of the past few decades, engineering of much larger numbers of transgenes became a reality, allowing to introduce full metabolic pathways from other organisms into plants and generate transgenics with startling new traits. From the advent of the classical plant genetic engineering, the transgenes were introduced into the nuclear genome of the plant cell, and this strategy still is quite successful when applied to few transgenes. However, for introducing large number of transgenes, we advocate that the chloroplast genome is a superior choice, especially for engineering of new complete metabolic pathways into plants. The ability to genetically engineer plants with complex and fully functional metabolic pathways from other organisms bears a substantial promise in generation of pharmaceuticals, i.e., biopharming, and new agricultural crops with that traits never existed before, leading to enhancement in quality of human life.

Figure 1.

Expression of the fully functional luciferase pathway in transplastomic tobacco plants results in autoluminescence. (A) Transplastomic plants emit light clearly visible to the human eye. (B) Transplastomic autoluminescent and wild-type plants in the dark and light. Images were acquired with a standard hand-held consumer-quality camera. The images are adapted from (Krichevsky et al., 2010).

Figure 2.

Major considerations for and against nuclear, plastid and mitochondrial transformations for genetic engineering of multigene pathways into plants.