Abstract

PALACIOS, M. Florencia et al. Estudio de la población del virus de la tristeza de los cítricos en cultivares de limoneros injertados en naranjo agrio y Citrus macrophylla. Rev. ind. agric. Tucumán [online]. 2020, vol.97, n.1, pp.27-33. ISSN 1851-3018.

Citrus tristeza virus (CTV) is the causal agent of the Tristeza disease, reported for the first time in Argentina in 1930. The most efficient vector, Toxoptera citricida (Kirkaldy), is present in the country and therefore citrus plants are made with tolerant combinations variety / rootstock. Lemon plants (Citrus limon (L) Burm f.) grafted on sour orange (Citrus x aurantium, L.) are asymptomatic and yield and growth are not affected by the virus. However, when lemon is grafted on Citrus macrophylla (Wester) the rootstock is severely affected by stem pitting and the tree becomes stunted. There are diverse CTV strains that differ in their ability to move and accumulate in different host species, and that host species exerts strong selective pressure on the virus. Because of this, the objective of this study was to compare the CTV population of different lemon cultivars grafted on sour orange and C. macrophylla in a field trial planted in December 2013 and exposed to natural infection. The strains of the virus presents were detected by reverse transcription and polymerase chain reaction (RT-PCR) using five sets of specific primers of CTV genotypes (T30, RB, B165, T3 and VT). The T3 and RB genotypes were detected in all the analyzed samples, while the T30 genotype was absent. Some lemon trees grafted on sour orange showed a lower concentration of T3 and / or absence of the VT genotype, both considered severe and present in all lemon tree samples in C. macrophylla. The genotype B165 was found for the first time in lemon in the northwestern Argentina, and it was present in 85% of the samples analyzed, in all cultivars. The natural infection and composition of the CTV population were very homogeneous in all plants of the trial, regardless of the rootstock. Results would indicate that C. macrophylla is susceptible to the genotypes detected.

Keywords : CTV; genotype; RT-PCR.

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