title: Development of marker-free transgenic lettuce resistant to Mirafiori lettuce big-vein virus.
abstract: Lettuce big-vein disease caused by Mirafiori lettuce big-vein virus (MLBVV) is found in major lettuce production areas worldwide, but highly resistant cultivars have not yet been developed. To produce MLBVV-resistant marker-free transgenic lettuce that would have a transgene with a promoter and terminator of lettuce origin, we constructed a two T-DNA binary vector, in which the first T-DNA contained the selectable marker gene neomycin phosphotransferase II, and the second T-DNA contained the lettuce ubiquitin gene promoter and terminator and inverted repeats of the coat protein (CP) gene of MLBVV. This vector was introduced into lettuce cultivars 'Watson' and 'Fuyuhikari' by Agrobacterium tumefaciens-mediated transformation. Regenerated plants (T0 generation) that were CP gene-positive by PCR analysis were self-pollinated, and 312 T1 lines were analyzed for resistance to MLBVV. Virus-negative plants were checked for the CP gene and the marker gene, and nine lines were obtained which were marker-free and resistant to MLBVV. Southern blot analysis showed that three of the nine lines had two copies of the CP gene, whereas six lines had a single copy and were used for further analysis. Small interfering RNAs, which are indicative of RNA silencing, were detected in all six lines. MLBVV infection was inhibited in all six lines in resistance tests performed in a growth chamber and a greenhouse, resulting in a high degree of resistance to lettuce big-vein disease. Transgenic lettuce lines produced in this study could be used as resistant cultivars or parental lines for breeding.
authors.affiliation: Institute of Vegetable and Floriculture Science, NARO, 360 Kusawa, Ano, Tsu, 514-2392, Mie, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kawazu
authors.affiliation: Institute of Vegetable and Floriculture Science, NARO, 360 Kusawa, Ano, Tsu, 514-2392, Mie, Japan.
authors.forename: Ryoi
authors.initials: R
authors.lastname: Fujiyama
authors.affiliation: Institute of Vegetable and Floriculture Science, NARO, 360 Kusawa, Ano, Tsu, 514-2392, Mie, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Imanishi
authors.affiliation: Institute of Vegetable and Floriculture Science, NARO, 360 Kusawa, Ano, Tsu, 514-2392, Mie, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukuoka
authors.affiliation: Institute of Vegetable and Floriculture Science, NARO, 360 Kusawa, Ano, Tsu, 514-2392, Mie, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Institute of Vegetable and Floriculture Science, NARO, 360 Kusawa, Ano, Tsu, 514-2392, Mie, Japan. ssmats@affrc.go.jp.|Tohoku Agricultural Research Center, NARO, 4 Akahira, Shimo-kuriyagawa, Morioka, 020-0198, Iwate, Japan. ssmats@affrc.go.jp.
authors.forename: Satoru
authors.initials: S
authors.lastname: Matsumoto
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics*; D005822:Genetic Vectors; D018545:Lactuca / Q000235:genetics* / Q000254:growth & development / Q000821:virology; D010935:Plant Diseases / Q000235:genetics* / Q000821:virology; D010942:Plant Viruses / Q000235:genetics / Q000472:pathogenicity; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000254:growth & development; D012328:RNA Viruses / Q000235:genetics / Q000472:pathogenicity; D014170:Transformation, Genetic
chemical_list: D004269:DNA, Bacterial; C036483:T-DNA
keywords: Lettuce big-vein disease; Marker-free; Mirafiori lettuce big-vein virus (MLBVV); Transgenic lettuce; Virus resistance