Reaction of transgenic Citrus sinensis plants to Citrus tristeza virus infection by Toxoptera citricida

• Published in: European journal of plant pathology Vol. 139; no. 1; pp. 151 - 159
• Main Authors: Muniz, Fabiana R, Souza, Amancio, Harakava, Ricardo, de Assis Alves Mourão Filho, Francisco, Stach-Machado, Dagmar R, Rezende, Jorge A. M, Febres, Vicente J, Moore, Gloria A, Mendes, Beatriz M. J
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01-05-2014; Springer Netherlands; Springer Nature B.V
• Subjects: Agriculture; Aphididae; Biomedical and Life Sciences; buds; Citrus fruits; Citrus sinensis; Citrus tristeza virus; clones; Cloning; Closterovirus; CS gene; Ecology; Fruits; gene expression; Genetic engineering; Grafting; Inoculation; inoculation methods; Life Sciences; Limonia; messenger RNA; mRNA; Multiplication; oranges; Pathogens; Pest resistance; Plant diseases; Plant Pathology; Plant resistance; Plant Sciences; Propagation; rootstocks; Toxoptera citricida; transgenes; Transgenic plants; Viruses; Vector inoculation; Pathogen derived resistance; Genetic engineering
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-013-0373-6

Transgenic Citrus sinensis ‘Hamlin’ and ‘Valencia’ plants containing Citrus tristeza virus (CTV)-derived sequences were propagated and inoculated with CTV. For propagation, selected buds from transgenic and non-transgenic control plants were grafted onto C. aurantium and C. limonia rootstock plants. CTV inoculation was performed via viruliferous aphids (Toxoptera citricida), and viral detection post-inoculation was performed through DASI-ELISA or RT-qPCR. After four inoculations, none of the transgenic lines tested showed complete resistance. However, viral multiplication was undetectable in some of the propagated clones. These resistant clones mainly came from transgenic ‘Valencia’ sweet orange plants grafted onto C. limonia rootstock containing the pCTV-CS gene construct. Although the tested viral inoculation method represents natural field infection conditions, the results did not differ significantly from those previously reported when the same transgenic lines were bud-graft inoculated. This finding indicates that the difficulties in producing CTV-resistant transgenic citrus lines may be unrelated to the inoculation method. Transgene expression level was quantified by RT-qPCR analysis and it was not possible to relate transgene mRNA level with resistance to the pathogen.