Biosynthesis of starch in tuberous crop plants

Ever since the introduction of the potato to Europe in the 16th century, cultivation and use of underground starchy crops of South American origin have become highly important in the face of globalization, exponential population growth, and climate change. Elucidating the mechanisms that drive the synthesis of tuber storage starch provides a better understanding as to how this pathway can be manipulated in a targeted manner to enhance starch synthesis and functionality in vivo. This chapter reviews starch biosynthesis primarily in potato, with reference to other underground starchy crops such as cassava and sweet potato. The initiation of the tuber and import of carbon to the amyloplast are discussed, followed by the action of critical enzymes, which synthesize the starch granule via granule initiation, amylose, and amylopectin synthesis. The unique properties of tuber starches and the manipulation of starch biosynthesis by specific gene targeting are further examined.