caa a22 4500 467894434 CHVBK 20180406152758.0 cr unu---uuuuu 170328e20060601xx s 000 0 eng 10.1007/s11103-006-0018-7 doi (NATIONALLICENCE)springer-10.1007/s11103-006-0018-7 Rai Mamta Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, 1108 The Strand, 301 University Blvd, Room 215-216, 77555-0632, Galveston, TX, USA aut Refinement of the Citrus Tristeza Virus Resistance Gene ( Ctv ) Positional Map in Poncirus trifoliata and Generation of Transgenic Grapefruit ( Citrus paradisi ) Plant Lines with Candidate Resistance Genes in this Region [Elektronische Daten] [Mamta Rai] Citrus tristeza virus (CTV) is a major pathogen of Citrus. A single dominant gene Ctv present in the trifoliate relative of Citrus, Poncirus trifoliata confers broad spectrum resistance against CTV. Refinement of genetic maps has delimited this gene to a 121kb region, comprising of ten candidate Ctv resistance genes. The ten candidate genes were individually cloned in Agrobacterium based binary vector and transformed into three CTV susceptible grapefruit varieties. Two of the candidate R-genes, R-2 and R-3 are exclusively expressed in transgenic plants and in Poncirus trifoliata, while five other genes are also expressed in non-transformed Citrus controls. Northern blotting with a CTV derived probe for assessment of infection in virus inoculated plants over a span of three growth periods, each comprising of six to eight weeks, indicates either an absence of initiation of infection or it's slow spread in R-2 plant lines or an initial appearance of infection and it's subsequent obliteration in some R-1 and R-4 plant lines. Limited genome walk up- and downstream form R-1 gene, based on it's 100% sequence identity between Poncirus and Citrus, indicates promoter identity of 92% between the two varieties. Further upstream and downstream sequencing indicates the presence of an O-methyl transferase and a Copia like gene respectively in Citrus instead of the amino acid transporter like gene upstream and a sugar transporter like gene downstream in Poncirus. The possibility of recombinations in the resistance locus of Citrus and the need for consistent monitoring for virus infection and gene expression in the transgenic Citrus trees is discussed. Springer, 2006 Citrus nationallicence Citrus tristeza virus nationallicence Poncirus trifoliata nationallicence positional cloning nationallicence transgenic grapefruit nationallicence Plant Molecular Biology Kluwer Academic Publishers 61/3(2006-06-01), 399-414 0167-4412 61:3<399 2006 61 11103 https://doi.org/10.1007/s11103-006-0018-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11103-006-0018-7 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Rai Mamta Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, 1108 The Strand, 301 University Blvd, Room 215-216, 77555-0632, Galveston, TX, USA aut NATIONALLICENCE 773 0- Plant Molecular Biology Kluwer Academic Publishers 61/3(2006-06-01), 399-414 0167-4412 61:3<399 2006 61 11103 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer