Identificación de fuentes de resistencia al Tomato leaf curl New Delhi virus in cucurbitáceas

Abstract

[ES] En 2013 se detectó una nueva virosis en el sudeste español que está causando estragos en los cultivos de cucurbitáceas. Se trata de una cepa del begomovirus Tomato leaf curl New Delhi virus (ToLCNDV). Como en todas las enfermedades de etiología viral, la mejor estrategia para controlar la enfermedad consiste en el desarrollo de variedades resistentes. Con ese fin, se tratará de poner a punto un protocolo de transmisión mecánica del virus y se cribará una colección de entradas de melón (Cucumis melo) y otra de calabacín y especies relacionadas (Cucurbita spp.). En todos los casos, la presencia del virus se confirmará mediante PCR.

[EN] In 2013, a new virus was detected in the south-east of Spain, creating serious problems to cucurbits crops. It was caused by a strain of the begomovirus Tomato leaf curl New Delhi virus (ToLCNDV), which is native to India. Like in every viral disease, the best way to control the pathogen is to develop resistant varieties by breeding programs. With that final goal, a protocol to transmit mechanically the virus was optimized and a screening of a collection of accessions of melon (Cucumis melo), zucchini and related species (Cucurbita spp) was performed. This screening was repeated twice, using two different inoculums: in one hand, the source of inoculum were field infected plants brought from a greenhouse in Almería; and in the other hand, it was used as inoculum leaves from agroinoculated plants with an infectious clone of the ToLCNDV. In all cases, the presence of the virus was confirmed by a semiquantitative PCR, in which two regions of viral genome were amplified. Similar results were obtained with both inoculums, but slightly more severe symptoms were observed when the infectious clone was used. Although the answer against the infection of ToLCNDV in Cucurbita moschata was variable, this specie was less susceptible than C. pepo, C. maxima and the majority of wild relatives. In consequence, it was possible to identify very promising accessions for pumpkin breeding against ToLCNDV. In relation with Cucumis melo, subsp. agrestis was more tolerant to the viral infection than subsp. melo, which seems to be highly susceptible.