title: Artificial microRNA-derived resistance to Cassava brown streak disease.
abstract: Artificial miRNAs (amiRNA) were generated targeting conserved sequences within the genomes of the two causal agents of Cassava brown streak disease (CBSD): Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). Transient expression studies on ten amiRNAs targeting 21nt conserved sequences of P1(CBSV and UCBSV), P3(CBSV and UCBSV), CI(UCBSV), NIb(CBSV and UCBSV), CP(UCBSV) and the un-translated region (3'-UTR) were tested in Nicotiana benthamiana. Four out of the ten amiRNAs expressed the corresponding amiRNA at high levels. Transgenic N. benthamiana plants were developed for the four amiRNAs targeting the P1 and NIb genes of CBSV and the P1 and CP genes of UCBSV and shown to accumulate miRNA products. Transgenic plants challenged with CBSV and UCBSV isolates showed resistance levels that ranged between ∼20-60% against CBSV and UCBSV and correlated with expression levels of the transgenically derived miRNAs. MicroRNAs targeting P1 and NIb of CBSV showed protection against CBSV and UCBSV, while amiRNAs targeting the P1 and CP of UCBSV showed protection against UCBSV but were less efficient against CBSV. These results indicate a potential application of amiRNAs for engineering resistance to CBSD-causing viruses in cassava.
authors.affiliation: National Crops Resources Research Institute, Namulonge, P.O. Box 7084, Kampala, Uganda; Makerere University, P.O. Box 7062, University Rd, Kampala, Uganda.
authors.forename: Henry
authors.initials: H
authors.lastname: Wagaba
authors.affiliation: ICAR-National Research Center on Plant Biotechnology, IARI, Pusa Campus, New Delhi 110012, India.
authors.forename: Basavaprabhu L
authors.initials: BL
authors.lastname: Patil
authors.affiliation: Makerere University, P.O. Box 7062, University Rd, Kampala, Uganda.
authors.forename: Settumba
authors.initials: S
authors.lastname: Mukasa
authors.affiliation: National Crops Resources Research Institute, Namulonge, P.O. Box 7084, Kampala, Uganda.
authors.forename: Titus
authors.initials: T
authors.lastname: Alicai
authors.affiliation: Centro Internacional de Agricultura Tropical, Cali, Apartado Aéreo 6713, Cali, Colombia.
authors.forename: Claude M
authors.initials: CM
authors.lastname: Fauquet
authors.affiliation: Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, USA. Electronic address: ntaylor@danforthcenter.org.
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Taylor
mesh_terms: D060467:Disease Resistance; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000276:immunology* / Q000821:virology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology*; D014026:Nicotiana / Q000235:genetics / Q000821:virology
chemical_list: D035683:MicroRNAs
keywords: Artificial microRNAs; Cassava brown streak disease; Cassava brown streak virus; Ugandan cassava brown streak virus; Virus resistance