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Raemakers, Krit; Schreuder, M.E.L.; Pereira, Isolde; Munyikwa, T.R.I.; Jacobsen, E.; Visser, Richard G. F.

doi:10.1023/a:1017574713880

Cited by 28 publications

(10 citation statements)

References 19 publications

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“…The genotypic effect on FEC production of cassava genotypes tested in this study was also observed in the FEC production of a range of Asian cassava genotypes (Raemakers et al, 2001) and recognized as one of the major limitations of the application of FEC in genetic transformation of farmer-preferred cultivars of cassava (Taylor et al, 1997; Fregene and Puonti-Kaerlas, 2002; Hankoua et al, 2005; Liu et al, 2011). These observations demonstrate that there might be an underlying genetic control in the capability of a given genotype to induce and proliferate FECs.…”

Section: Resultssupporting

confidence: 66%

“…A procedure to transform landraces from the TME series has been recently developed (Zainuddin et al, 2012) at ETH Zurich and also used successfully to transform the industry-preferred cultivar T200 in South Africa (Chetty et al, 2013). However, transformation of cassava cultivars particularly preferred by African farmers remains challenging because FEC production tends to be genotype-dependent and regeneration of transformed FEC is often problematic (Raemakers et al, 2001; Chetty et al, 2013). …”

Section: Introductionmentioning

confidence: 99%

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Unlocking the potential of tropical root crop biotechnology in east Africa by establishing a genetic transformation platform for local farmer-preferred cassava cultivars

et al. 2013

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Cassava genetic transformation capacity is still mostly restricted to advanced laboratories in the USA, Europe and China; and its implementation and maintenance in African laboratories has remained scarce. The impact of transgenic technologies for genetic improvement of cassava will depend largely on the transfer of such capabilities to researchers in Africa, where cassava has an important socioeconomic niche. A major constraint to the development of genetic transformation technologies for cassava improvement has been the lack of an efficient and robust transformation and regeneration system. Despite the success achieved in genetic modification of few cassava cultivars, including the model cultivar 60444, transgenic cassava production remains difficult for farmer-preferred cultivars. In this study, a protocol for cultivar 60444 developed at ETH Zurich was successfully implemented and optimized to establish transformation of farmer-preferred cassava cultivars popular in east Africa. The conditions for production and proliferation of friable embryogenic calli (FEC) and Agrobacterium-mediated transformation were optimized for three east African farmer-preferred cultivars (Ebwanatereka, Kibandameno and Serere). Our results demonstrated transformation efficiencies of about 14–22 independent transgenic lines per 100 mg of FEC for farmer-preferred cultivars in comparison to 28 lines per 100 mg of the model cultivar 60444. The presence, integration and expression of the transgenes were confirmed by PCR, Southern blot analysis and histochemical GUS assay. This study reports the establishment of a cassava transformation platform at International Institute of Tropical Agriculture (IITA) hosted by Biosciences eastern and central Africa (BecA) hub in Kenya and provides the basis for transferring important traits such as virus resistance and prolonged shelf-life to farmer-preferred cultivars in east Africa. We anticipate that such platform will also be instrumental to transfer technologies to national agricultural research systems (NARS) in sub-Saharan Africa.

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Section: Resultssupporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Unlocking the potential of tropical root crop biotechnology in east Africa by establishing a genetic transformation platform for local farmer-preferred cassava cultivars

et al. 2013

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“…Calli from the other seven lines showed reduced growth, and did not yield PCR-positive colonies. Despite years of experience in transforming cassava (Raemakers et al 1993a, b, 2001, 2005) it is still very difficult to combine optimum growth conditions of the FEC lines with optimal A. tumefaciens receptiveness.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2011

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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.

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“…This step is a key parameter of the protocol because FEC production as well as their capacity to proliferate and regenerate are strongly genotype-dependent [16,20,23]. …”

Section: Methodsmentioning

confidence: 99%

“…Improvement of farmer-preferred genotypes using Agrobacterium -mediated transformation of FEC, however, has been limited by the difficulty of generating plant tissue suitable for transformation, the low regeneration efficiency of FEC, and the time necessary for embryo maturation following their co-cultivation with Agrobacterium [8]. In particular, FEC initiation and time to regeneration are genotype dependent [20,21]. …”

Section: Introductionmentioning

confidence: 99%

Robust transformation procedure for the production of transgenic farmer-preferred cassava landraces

et al. 2012

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Recent progress in cassava transformation has allowed the robust production of transgenic cassava even under suboptimal plant tissue culture conditions. The transformation protocol has so far been used mostly for the cassava model cultivar 60444 because of its good regeneration capacity of embryogenic tissues. However, for deployment and adoption of transgenic cassava in the field it is important to develop robust transformation methods for farmer- and industry-preferred landraces and cultivars. Because dynamics of multiplication and regeneration of embryogenic tissues differ between cassava genotypes, it was necessary to adapt the efficient cv. 60444 transformation protocol to genotypes that are more recalcitrant to transformation. Here we demonstrate that an improved cassava transformation protocol for cv. 60444 could be successfully modified for production of transgenic farmer-preferred cassava landraces. The modified transformation method reports on procedures for optimization and is likely transferable to other cassava genotypes reportedly recalcitrant to transformation provided production of high quality FEC. Because the three farmer-preferred cassava landraces selected in this study have been identified as resistant or tolerant to cassava mosaic disease (CMD), the adapted protocol will be essential to mobilize improved traits into cassava genotypes suitable for regions where CMD limits production.

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Untitled

Cited by 28 publications

References 19 publications

Unlocking the potential of tropical root crop biotechnology in east Africa by establishing a genetic transformation platform for local farmer-preferred cassava cultivars

Unlocking the potential of tropical root crop biotechnology in east Africa by establishing a genetic transformation platform for local farmer-preferred cassava cultivars

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

Robust transformation procedure for the production of transgenic farmer-preferred cassava landraces

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