Synthesis of novel starches in planta: Opportunities and challenges

In addition to being the main source of energy in the human diet, starch is also used for a wide variety of industrial processes. Potato, maize, wheat and cassava are the major sources for industrial starch. While there are significant species-dependent differences among these starches, in most cases it is necessary to chemically or physically modify the starches in order to meet the various industrial needs. The advent of molecular biology and genetic engineering has provided the requisite technologies to produce starches in planta with improved properties, which may reduce or eliminate the need for in vitro starch modification. In the last decade significant progress in our understanding of starch biosynthesis has been achieved through the use of these technologies. In this review, starch structure, functionality and use in industry are discussed. The recent discoveries in the area of starch biosynthesis are reviewed and several potential plant breeding and/or genetic engineering strategies for the modification of starch synthesis in planta are presented.