naa a22 4500 52878689X 20180924065502.0 cr unu---uuuuu 180924e20120925xx s 000 0 eng 10.3929/ethz-b-000057986 doi 10.1371/journal.pone.0045277 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/57986 Exploiting the Combination of Natural and Genetically Engineered Resistance to Cassava Mosaic and Cassava Brown Streak Viruses Impacting Cassava Production in Africa [Elektronische Daten] [Hervé Vanderschuren, Isabel Moreno, Ravi B. Anjanappa, Ima M. Zainuddin, Wilhelm Gruissem] PLoS ONE Open access ethresearch Cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) are currently two major viral diseases that severely reduce cassava production in large areas of Sub-Saharan Africa. Natural resistance has so far only been reported for CMD in cassava. CBSD is caused by two virus species, Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). A sequence of the CBSV coat protein (CP) highly conserved between the two virus species was used to demonstrate that a CBSV-CP hairpin construct sufficed to generate immunity against both viral species in the cassava model cultivar (cv. 60444). Most of the transgenic lines showed high levels of resistance under increasing viral loads using a stringent top-grafting method of inoculation. No viral replication was observed in the resistant transgenic lines and they remained free of typical CBSD root symptoms 7 month post-infection. To generate transgenic cassava lines combining resistance to both CBSD and CMD the hairpin construct was transferred to a CMD-resistant farmer-preferred Nigerian landrace TME 7 (Oko-Iyawo). An adapted protocol allowed the efficient Agrobacterium-based transformation of TME 7 and the regeneration of transgenic lines with high levels of CBSV-CP hairpin-derived small RNAs. All transgenic TME 7 lines were immune to both CBSV and UCBSV infections. Further evaluation of the transgenic TME 7 lines revealed that CBSD resistance was maintained when plants were co-inoculated with East African cassava mosaic virus (EACMV), a geminivirus causing CMD. The innovative combination of natural and engineered virus resistance in farmer-preferred landraces will be particularly important to reducing the increasing impact of cassava viral diseases in Africa. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Vanderschuren Hervé joint author Moreno Isabel joint author Anjanappa Ravi B. joint author Zainuddin Ima M. joint author Gruissem Wilhelm joint author PLoS ONE Lawrence, KS, USA : Public Library of Science 7 (9), p. e45277 1932-6203 http://hdl.handle.net/20.500.11850/57986 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/57986 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Vanderschuren Hervé joint author ETHRESEARCH 700 1- Moreno Isabel joint author ETHRESEARCH 700 1- Anjanappa Ravi B. joint author ETHRESEARCH 700 1- Zainuddin Ima M. joint author ETHRESEARCH 700 1- Gruissem Wilhelm joint author ETHRESEARCH 773 0- PLoS ONE Lawrence, KS, USA : Public Library of Science 7 (9), p. e45277 1932-6203 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access