Genetic manipulation of starch properties in plants: patents 2001-2006.

Starch is the major energy store for many plants and has been extensively exploited by humans for millennia, first as a food source and more recently in a wide variety of non-food applications. The starch properties of the plant species which were first selected by humans have been improved for some time, first by the identification and selection of genotypes with favourable natural variation, then by a process of controlled crosses and selection of offspring with desirable traits and more recently by the generation of synthetic mutants and transgenic plants. Many genes involved in starch synthesis have been identified at the molecular level, providing the means of both manipulating starch properties in novel ways and defining how useful changes to the starch have been made. The commercial value of this understanding is reflected in the expansion of the patent literature where knowledge surrounding each of the genes of starch biosynthesis has been protected in the patent literature. Changes to starch structure have been made using transgenic and conventional breeding methods and these methods are described in the patent literature. Transgenic approaches usually either reduce the activity of an endogenous protein or replace an endogenous protein with a protein from another species. Conventional breeding still plays a role in the recent patent literature and has been used to create new combinations of alleles which in turn generates starch with novel properties.