Open AccessAccumulation of transgene‐derived siRNAs is not sufficient for RNAi‐mediated protection against Citrus tristeza virus in transgenic Mexican lime
Author(s) -
LÓPEZ CARMELO,
CERVERA MAGDALENA,
FAGOAGA CARMEN,
MORENO PEDRO,
NAVARRO LUIS,
FLORES RICARDO,
PEÑA LEANDRO
Publication year - 2010
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/j.1364-3703.2009.00566.x
Subject(s) - citrus tristeza virus , transgene , biology , rna interference , virology , genetically modified crops , small interfering rna , virus , lime , gene , genetics , plant virus , rna , paleontology
SUMMARY Mexican lime plants transformed with the 3′‐terminal 549 nucleotides of the Citrus tristeza virus (CTV) genome in sense, antisense and intron‐hairpin formats were analysed for transgene‐derived transcript and short interfering RNA (siRNA) accumulation, and for CTV resistance. Propagations from all sense, antisense and empty‐vector transgenic lines were susceptible to CTV, except for a single sense‐line plant with a complex transgene integration pattern that showed transgene‐derived siRNAs in association with low levels of the transgene‐derived transcript. In contrast, nine of 30 intron‐hairpin lines showed CTV resistance, with 9%–56% of bud‐propagated plants, depending on the line, remaining uninfected on graft inoculation, and the others being susceptible. Although resistance was always associated with the presence of transgene‐derived siRNAs, their level in different sense and intron‐hairpin transformants was variable irrespective of the response to CTV infection. In intron‐hairpin lines with single transgene integration, CTV resistance was correlated with low accumulation of the transgene‐derived transcript rather than with high accumulation of transgene‐derived siRNAs.