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Poster68: Multiple strategies to enhance the accumulation of pro-Vit A in cassava roots


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Poster for CIAT 2009 Knowledge Sharing Week

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Poster68: Multiple strategies to enhance the accumulation of pro-Vit A in cassava roots

  1. 1. Multiple strategies to enhance the accumulation of pro-Vit A in cassava roots Chavarriaga P1, Beltrán J1, Ladino J1, Vacca O1, López D1, Arango J2, Al-Babili S2, Beyer P2, and Tohme J1 Beltrá Ló Al- 1. Conservation and Use of Tropical Genetic Resources, CIAT, AA 6713 , Cali, Colombia 2. Albert-Ludwigs-Universitat Freiburg, Center for Applied 6713 Albert- Ludwigs- Biosciences, Schanzlestr 1, D-79104, Freiburg, Germany D- INTRODUCTION • CrtB, Y and I transcripts from in vitro roots We are introducing three genes (crtB, crtY and crtI) of the carotene The expression of the three genes was detected in in-vitro roots and synthesis pathway from E. urodevora into cassava cultivars to increase β- leaves, indicating that the Patatin and Patatin I promoters may be active carotene in roots. These genes are under the control of root specific on both organs in young plants. promoters isolated from cassava, sugar beet and potato. Based on evidence from other crops like potato, it is expected that the expression 1kb 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 of this pathway, which converts GGPP into β-carotene, may turn out to CrtB be a more efficient way of increasing the pro-VitA content in cassava Expression in than introducing just one crtB gene. Plants have been regenerated and CrtY in vitro fibrous confirmed transgenic via real time RT-PCR. Some lines are planted in roots CrtI the field. 18S METHODS Gene constructs provided by The Albert-Ludwigs-Universitat Freiburg. • Orange Embryos 35S npt II Pat CrtY Pat I CrtB Pat CrtI 1) Some transgenic lines developed orange embryos that seemed to LB RB accumulate high levels of carotenes in cotyledons, an starch- 35S hpt II Ext CrtY Ext CrtB Ext CrtI 2) accumulating organ. Evidence of the activity of the promoters LB RB Patatin and Patatin I in this organ was therefore observed. 35S hpt II Mll CrtY Mll CrtB Mll CrtI 3) LB RB • T0-pPatErwII plants in vitro, greenhouse and field T0 plants were regenerated mostly from green embryos and are being 1) pPatErwII Patatin from Potatoes planted in the field. 2) pCAExtThree Extensin from Cassava Roots 3) pCASBGolden Major Latex Like Protein from Sugar Beet Transformation of Friable Embryogenic Callus Model cultivar 60444 was transformed using Agrobacterium tumefaciens (Agl1). Over 150 cell lines were established from orange, yellow and creamish-colored calli CONCLUSIONS AND PERSPECTIVES • Besides introducing a single crtB gene, we are complementing the strategy to increase β-carotene content in cassava roots by introducing three (crtY, crtB, crtI) genes of the pathway. RESULTS AND DISCUSSION •The Patatin and Patatin I promoter seem to be active in leaves, roots • Real-time PCR transgene detection in eleven T0-pPatErwII and cotyledons of cassava. plants Transgenic pPatErwII • It has been possible to regenerate transgenic plants from green H2O embryos carrying the three genes. They are being planted in the field for NT 1kb --------------------------TRANSGENICS---------------------------- further analysis. crtB •Our strategy is being complemented by transforming yellow-rooted cultivars from Brazil and Colombia, and one ACMD resistant cultivar crtY from Nigeria. crtI Date prepared: July 2008