The mode of photosynthesis performed by Crassulacean acid metabolism (CAM) plants provides a powerful strategy that allows them to acclimate and adapt to dry, high-insolation habitats. A few agronomically important CAM species have been exploited in semi-arid regions because they can be grown in areas where precipitation is inadequate for most common crops. Major cultivated CAM species include pineapple, agave and prickly pear cactus.
Most of these species can achieve near-maximal productivity with only about 20% of precipitation needed for conventional crops. Above ground biomass of CAM species can exceed those of common cultivated crops, but are less than C4 crops like corn and sugar cane.
However, crop water demand for CAM crop species is approximately 20% of C4 crops. Furthermore, the growth characteristics of these CAM crops, such as:
- tolerance to drought,
- high temperatures,
- high solar irradiation,
- resistance to herbivores,
- high shoot to root ratios,
- high non-structural carbohydrate contents, and
- low lignin content
make them attractive for cultivation as bioenergy crops.
The specific goals of this project are to improve the energy density of prickly pear cactus by targeted conversion of polysaccharide (i.e., soluble sugars and starch) biosynthesis to lipid biosynthesis and accumulation, and to develop research tools to further advance our molecular genetic understanding of prickly pear as feedstocks.