Field testing and exploitation of genetically modified cassava with low-amylose or amylose-free starch in Indonesia

Abstract

The development and testing in the field of genetically modified -so called- orphan crops like cassava in tropical countries is still in its infancy, despite the fact that cassava is not only used for food and feed but is also an important industrial crop. As traditional breeding of cassava is difficult (allodiploid, vegetatively propagated, outbreeding species) it is an ideal crop for improvement through genetic modification. We here report on the results of production and field testing of genetically modified low-amylose transformants of commercial cassava variety Adira4 in Indonesia. Twenty four transformants were produced and selected in the Netherlands based on phenotypic and molecular analyses. Nodal cuttings of these plants were sent to Indonesia where they were grown under biosafety conditions. After two screenhouse tests 15 transformants remained for a field trial. The tuberous root yield of 10 transformants was not significantly different from the control. Starch from transformants in which amylose was very low or absent showed all physical and rheological properties as expected from amylose-free cassava starch. The improved functionality of the starch was shown for an adipate acetate starch which was made into a tomato sauce. This is the first account of a field trial with transgenic cassava which shows that by using genetic modification it is possible to obtain low-amylose cassava plants with commercial potential with good root yield and starch quality.Electronic supplementary materialThe online version of this article (doi:10.1007/s11248-011-9507-9) contains supplementary material, which is available to authorized users.

Optimisation of a somatic embryogenesis and transformation protocol for farmer-preferred cassava cultivars in Kenya

“…2, Table 4). This shows that cassava transformation remains genotype dependent, and variability in transformation efficiencies between independent procedures cannot be totally eliminated as previously reported (Koehorst-van Putten et al, 2012).…”

Recent Biotechnological Advances in the Improvement of Cassava

“…Therefore, for industrial purposes, starch is often treated with chemicals in order to make the amylose less sensitive to crystallization [18]. As retrogradation is caused mainly by the amylose fraction in starch, amylose-free starches do not have to be treated with chemicals [19]. There are therefore efforts to generate amylose-free cassava through genetic engineering; for example, starch-free cassava was obtained by silencing GBSSI, the granule-bound starch synthase gene, which is required for the synthesis of amylose [20].…”

Thermomechanical characterization of an amylose-free starch extracted from cassava (Manihot esculenta, Crantz)

“…Transgenic genotypes (from TMS60444 and Adira 4 of African and Indonesian origin, respectively) producing low amylose starch have been obtained through inhibition of the enzyme (GBSSI) responsible for the amylose synthesis these new (Koehorst-van Putten et al, 2012;Zhao, Dufour, Sánchez, Ceballos, & Zhang, 2011). The discovery of a waxy starch cassava (AM206-5 clone), is the product of a spontaneous mutation identified after self-pollinating a large number of accessions from the germplasm collection (Ceballos et al, 2007).…”