Analogues of virus resistance genes map to QTLs for resistance to sharka disease in Prunus davidiana

Abstract

Plum pox virus (PPV), the causative agent of sharka disease in Prunoideae, is one of the most serious problems affecting stone fruit production in Europe and America. Resistance to PPV was previously described in a Prunus davidiana clone, P1908, and introduced into peach (Prunus persica) genotypes. Genetic resistance to PPV displays a complex pattern of quantitative inheritance. An analysis of quantitative trait loci (QTLs) for resistance was performed on an F1 interspecific peach population obtained from a cross between the susceptible nectarine cultivar Summergrand and P. davidiana. The hybrids were graft-inoculated with PPV in duplicate following a classical procedure. The incidence of infection was evaluated four times, over two vegetative cycles, by symptom observation and enzyme-linked immunoadsorbent assays (ELISA). Restriction of systemic downward movement of the PPV virus was also evaluated by testing the susceptible rootstocks. Using both analysis of variance and non-parametric tests, six genomic regions involved in PPV resistance were detected. Depending on the scoring data considered, between 22 and 51% of the phenotypic variance could be explained by the quantitative model. One QTL, located in the distal region of linkage group 1, maps in a genomic region that is syntenic to the location of a resistance gene previously identified in the apricot cv. Goldrich. Some QTLs appeared to be temporally specific, reflecting the environmental dependence of PPV-resistance scoring. Candidate gene fragments were amplified by PCR, isolated and mapped on the peach interspecific linkage map. We report here the co-localization of three analogues of virus resistance genes with two distinct genomic regions linked to PPV resistance in P. davidiana.

New approaches to Prunus transcriptome analysis

“…A group of DAM (dormancyassociated) SVP-like (Short Vegetative Phase) MADS-box genes have been described to be responsible for this absence of vegetative dormancy in peach Jiménez et al 2010a, b). In apricot, candidate genes have been assayed in the study of Plum pox virus (PPV) resistance including resistance gene analogs (RGA) (Dondini et al, 2004;Decroocq et al 2005;Lalli et al 2005), nucleotide binding site-leucine-rich repeat (NBS-LRR) (Soriano et al 2005), eukaryotic translation initiation factor (eIF4E), RNA helicase SDE3 (Cd93) and Argonaut AGO1 protein (Marandel et al 2009). In addition, several works have made possible the identification of candidate gene coding for enzymes involved in apricot ripening, such as ACC oxidase (Mbé-guié et al 1999); polyphenol oxidase (Chevalier et al 1999); enzymes involved in the softening process (Mbé-guié et al 2002); cell wall, sugar, lipid, organic acid, and protein metabolism (Geuna et al (2005) and enzymes involved in apricot aroma (González-Agüero et al 2009).…”

Identification of Quantitative Trait Loci Controlling Symptom Development During Viral Infection inArabidopsis thaliana

“…Such polygenic control is the case with the A. thaliana-Cauliflower mosaic virus pathosystem, for which three distinct quantitative trait loci (QTL) have been identified (Callaway et al 2000). Similarly, quantitative symptom determinants have also been identified in several other pathosystems such as pepper-CMV (Ben Chaim et al 2001), tomato-Tomato yellow leaf curl virus (Zamir et al 1994), and Prunus davidiana-Plum pox virus (PPV) (Decroocq et al 2005). However, none of these genes have been cloned yet.…”

Evaluation of the Prunus interspecific progenies for resistance to Plum pox virus

“…The first study of genetic factors involved in resistance to PPV in Prunus davidiana was reported in Decroocq et al (2005). It used an F 1 population derived from a cross between P. persica cultivar Summergrand and P. davidiana clone P1908 and reported a quantitative trait loci (QTLs) analysis which identified six genomic regions related to PPV resistance in P. davidiana P1908 and thus demonstrated the polygenic character of the resistance carried by this clone.…”

“…In peach (Prunus persica /L./ Batsch), all cultivars are susceptible to PPV and the only potential resistance source available Prunus davidiana clone P1908 (Anonymous 1974;Decroocq et al 2005) has been identified up to now. Thus, the isolation and incorporation of genes for resistance to sharka disease into P. persica would be of significant economic and environmental benefit.…”