title: Resistance to Sri Lankan cassava mosaic virus (SLCMV) in genetically engineered cassava cv. KU50 through RNA silencing.
abstract: Cassava ranks fifth among the starch producing crops of the world, its annual bioethanol yield is higher than for any other crop. Cassava cultivar KU50, the most widely grown cultivar for non-food purposes is susceptible to Sri Lankan cassava mosaic virus (SLCMV). The objective of this work was to engineer resistance to SLCMV by RNA interference (RNAi) in order to increase biomass yield, an important aspect for bioethanol production. Here, we produced transgenic KU50 lines expressing dsRNA homologous to the region between the AV2 and AV1 of DNA A of SLCMV. High level expression of dsRNA of SLCMV did not induce any growth abnormality in the transgenic plants. Transgenic lines displayed high levels of resistance to SLCMV compared to the wild-type plants and no virus load could be detected in uninoculated new leaves of the infected resistant lines after PCR amplification and RT-PCR analysis. The agronomic performance of the transgenic lines was unimpaired after inoculation with the virus as the plants presented similar growth when compared to the mock inoculated control plants and revealed no apparent reduction in the amount and weight of tubers produced. We show that the resistance is correlated with post-transcriptional gene silencing because of the production of transgene specific siRNA. The results demonstrate that transgenic lines exhibited high levels of resistance to SLCMV. This resistance coupled with the desirable yield components in the transgenic lines makes them better candidates for exploitation in the production of biomass as well as bioethanol.
authors.affiliation: Laboratory of Plant Cell Technology, Graduate School of Horticulture, Chiba University, Chiba, Japan; Department of Genetics/Biotechnology, Faculty of Science, University of Calabar, Calabar, Nigeria.
authors.forename: Valentine Otang
authors.initials: VO
authors.lastname: Ntui
authors.affiliation: Laboratory of Plant Cell Technology, Graduate School of Horticulture, Chiba University, Chiba, Japan; Cambodia Agricultural Research and Development Institute, Phnom Penh, Cambodia.
authors.forename: Kynet
authors.initials: K
authors.lastname: Kong
authors.affiliation: Laboratory of Plant Cell Technology, Graduate School of Horticulture, Chiba University, Chiba, Japan; Department of Biotechnology, Abdul Wali Khan University, Mardan, Pakistan.
authors.forename: Raham Sher
authors.initials: RS
authors.lastname: Khan
authors.affiliation: Laboratory of Plant Cell Technology, Graduate School of Horticulture, Chiba University, Chiba, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Igawa
authors.affiliation: Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, India.
authors.forename: Gnanaguru Janaky
authors.initials: GJ
authors.lastname: Janavi
authors.affiliation: Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, India.
authors.forename: Ramalingam
authors.initials: R
authors.lastname: Rabindran
authors.affiliation: Laboratory of Plant Cell Technology, Graduate School of Horticulture, Chiba University, Chiba, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Nakamura
authors.affiliation: Laboratory of Plant Cell Technology, Graduate School of Horticulture, Chiba University, Chiba, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mii
mesh_terms: D053839:Begomovirus / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics; D005818:Genetic Engineering; D002365:Manihot / Q000235:genetics / Q000254:growth & development / Q000821:virology*; D009029:Mosaic Viruses / Q000235:genetics*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000821:virology; D018515:Plant Leaves / Q000821:virology; D030821:Plants, Genetically Modified / Q000821:virology*; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering / Q000235:genetics*
chemical_list: D004279:DNA, Viral; D034741:RNA, Small Interfering