As the world’s population continues to increase to more than seven billion people, heavy demands have been placed on the food supply, due, in part, by the diversion of farmland for economic development, increasing demand for crops as food and feed, and the use of important food crops in the production of renewable energy. Because of these factors, there has been great concern whether there will be enough food available to feed the global population, especially in light of evidence suggesting current crop production may have peaked and cannot sustain the nine billion people predicted to inhabit the earth by the year 2050.
Since many of the important food crops consumed by humans, including rice and wheat, utilize C3 photosynthesis for carbon dioxide assimilation, their productivity is severely diminished under hot and dry conditions. As a mechanism to adapt to these environmental conditions, some plants have evolved C4 photosynthesis, by which specialized cell types and biochemistry have developed and are dedicated towards the concentration of carbon dioxide around Rubisco, the primary enzyme involved in carbon fixation during photosynthesis, which enables them to gain greater water and nutrient use efficiency. Therefore, it would be advantageous to engineer C4-like properties into C3 crops, such as rice, to potentially improve yields.