Rice starch biotechnology: Rice endosperm as a model of cereal endosperms

During the last couple of decades, rapid progress has been made in increasing our understanding of the specific contributions of the most important enzymes to starch biosynthesis in cereal endosperms, particularly in rice endosperm. Now, we can basically predict how and to what extent the starch-related phenotypes can be modified in the endosperm in accordance with alterations of activities of single or simultaneously multiple starch biosynthetic isozymes. Thus, starch bioengineering in planta is now a most particularly promising field of plant biotechnology. Here, an overview of the present status of biochemical, molecular, and genetic research is presented, regarding starch biosynthesis and its engineering for the generation of new cultivars with improved cooking or novel functional properties of starch in rice endosperm. A huge number and variety of cultivars have been developed and cultivated mainly in paddy fields of Asian countries because rice is the most important staple food grain there. The availability of such invaluable genetic resources, as well as databases for various types of mutants, complete genome sequences, and omics tools should ensure further progress in the rice starch biotechnology research field.