Background: Fruit appearance of apple (Malus domestica Borkh.) is accession-specific and one of the main criteria for consumer choice. Consequently, fruit appearance is an important selection criterion in the breeding of new cultivars.
View Article and Find Full Text PDFGreat diversity of shape, size, and skin color is observed among the fruits of different apple genotypes. These traits are critical for consumers and therefore interesting targets for breeding new apple varieties. However, they are difficult to phenotype and their genetic basis, especially for fruit shape and ground color, is largely unknown.
View Article and Find Full Text PDFCisgenesis, the genetic modification of a plant with genes from a sexually compatible plant, was used to confer fire blight resistance to the cultivar 'Gala Galaxy' by amendment of the resistance gene FB_MR5, resulting in the line C44.4.146.
View Article and Find Full Text PDFGenetic modification of apple cultivars through cisgenesis can introduce traits, such as disease resistance from wild relatives, quickly and without crossing. This approach was used to generate the cisgenic apple line C44.4.
View Article and Find Full Text PDFRapid cycle breeding uses transgenic early flowering plants as crossbreed parents to facilitate the shortening of breeding programs for perennial crops with long-lasting juvenility. Rapid cycle breeding in apple was established using the transgenic genotype T1190 expressing the gene of silver birch. In this study, the genomes of T1190 and its non-transgenic wild-type PinS (F1-offspring of 'Pinova' and 'Idared') were sequenced by Illumina short-read sequencing in two separate experiments resulting in a mean sequencing depth of 182× for T1190 and 167× for PinS.
View Article and Find Full Text PDFMost of the commercial apple cultivars are highly susceptible to fire blight, which is the most devastating bacterial disease affecting pome fruits. Resistance to fire blight is described especially in wild Malus accessions such as M. × robusta 5 (Mr5), but the molecular basis of host resistance response to the pathogen Erwinia amylovora is still largely unknown.
View Article and Find Full Text PDFBreeding for resistance against the destructive fire blight disease of apples is the most sustainable strategy to control the menace of this disease, and has become increasingly important in European apple breeding programs. Since most cultivars are susceptible, wild accessions have been explored for resistance with quantitative trait loci detected in a few wild species. Fire blight resistance of was described following phenotypic evaluations with a C-type strain of , Ea222_JKI, and the detection of a major QTL on chromosome 10 () of this crabapple.
View Article and Find Full Text PDFThe approach presented here can be applied to reduce the time needed to introduce traits from wild apples into null segregant advanced selections by one-fourth. Interesting traits like resistances to pathogens are often found within the wild apple gene pool. However, the long juvenile phase of apple seedlings hampers the rapid introduction of these traits into new cultivars.
View Article and Find Full Text PDFPhyllosticta ampelicida causes black rot disease of Vitis spp. Genetic homogeneity of pathogen populations was investigated by analyzing the number of haplotypes present in infected samples from Europe and America. The fungus was identified from an analysis of the internal transcribed spacer (ITS)1-ITS2 region, and partial sequences of β-tubulin and calmodulin genes.
View Article and Find Full Text PDFThe loop-mediated isothermal amplification (LAMP) allows the rapid and specific amplification of target DNA under isothermal conditions without a prior DNA purification step. Moreover, successful amplifications can be directly evaluated through a color change of the reaction solutions. Here, we describe two LAMP assays for the detection of ochratoxin-A producing black aspergilli isolated from grapes.
View Article and Find Full Text PDFThe generation and selection of novel fire blight resistant apple genotypes would greatly improve the management of this devastating disease, caused by Erwinia amylovora. Such resistant genotypes are currently developed by conventional breeding, but novel breeding technologies including cisgenesis could be an alternative approach. A cisgenic apple line C44.
View Article and Find Full Text PDFThe expression of the apple scab resistance gene Rvi6 in different apple cultivars and lines is not modulated by biotic or abiotic factors. All commercially important apple cultivars are susceptible to Venturia inaequalis, the causal organism of apple scab. A limited number of apple cultivars were bred to express the resistance gene Vf from the wild apple genotype Malus floribunda 821.
View Article and Find Full Text PDFUpon pathogen attack, fruit trees such as apple (Malus spp.) and pear (Pyrus spp.) accumulate biphenyl and dibenzofuran phytoalexins, with aucuparin as a major biphenyl compound.
View Article and Find Full Text PDFA set of differential hosts has recently been identified for 17 apple scab resistance genes in an updated system for defining gene-for-gene (GfG) relationships in the Venturia inaequalis-Malus pathosystem. However, a set of reference isolates characterized for their complementary avirulence alleles is not yet available. In this paper, we report on improving the set of differential hosts for h(7) and propose the apple genotype LPG3-29 as carrying the single major resistance gene Rvi7.
View Article and Find Full Text PDFThe fire blight susceptible apple cultivar Malus × domestica Borkh. cv. 'Gala' was transformed with the candidate fire blight resistance gene FB_MR5 originating from the crab apple accession Malus × robusta 5 (Mr5).
View Article and Find Full Text PDFOntogenic scab resistance in apple leaves and fruits is a horizontal resistance against the plant pathogen Venturia inaequalis and is expressed as a decrease in disease symptoms and incidence with the ageing of the leaves. Several studies at the biochemical level tried to unveil the nature of this resistance; however, no conclusive results were reported. We decided therefore to investigate the genetic origin of this phenomenon by performing a full quantitative transcriptome sequencing and comparison of young (susceptible) and old (ontogenic resistant) leaves, infected or not with the pathogen.
View Article and Find Full Text PDFUsing resistance genes from a crossable donor to obtain cultivars resistant to diseases and the use of such cultivars in production appears an economically and environmentally advantageous approach. In apple, introgression of resistance genes by classical breeding results in new cultivars, while introducing cisgenes by biotechnological methods maintains the original cultivar characteristics. Recently, plants of the popular apple 'Gala' were genetically modified by inserting the apple scab resistance gene Rvi6 (formerly HcrVf2) under control of its own regulatory sequences.
View Article and Find Full Text PDFA quantitative real-time polymerase chain reaction (qPCR) was developed and validated for quantification of Venturia inaequalis in infected leaf tissue of Malus × domestica. The method is based on dual-labeled hybridization probes, allowing simultaneous detection of host and pathogen DNA within one single reaction. Limit of quantification for the pathogen was 0.
View Article and Find Full Text PDFGuignardia bidwellii is the etiological agent of grape black rot, a disease affecting Vitis and other Vitaceae that can cause heavy crop losses in vineyards. Its identification is based mainly on morphological characters and the symptoms on plants but, due to their variability, they may be difficult to interpret to reliably distinguish the pathogen to species. To date, despite the economic importance of G.
View Article and Find Full Text PDFCisgenesis represents a step toward a new generation of GM crops. The lack of selectable genes (e.g.
View Article and Find Full Text PDFMol Plant Pathol
June 2011
Fire blight is the most destructive bacterial disease affecting apple (Malus×domestica) worldwide. So far, no resistance gene against fire blight has been characterized in apple, despite several resistance regions having been identified. A highly efficacious resistance quantitative trait locus (QTL) was localized on linkage group 12 (LG12) of the ornamental cultivar 'Evereste'.
View Article and Find Full Text PDFDurable resistance to apple scab (Venturia inaequalis (Cke) Wint; anamorph Spilocaea pomi Fries) is one of the major goals of apple (Malus) breeding programs. Since current scab resistance breeding is heavily reliant on genes with gene-for-gene relationships, a good understanding of the genetic basis of host-pathogen interactions needs to be developed for this strategy to be successful. While the genomic organization of apple scab resistance genes has been studied extensively, little is known about the avirulence genes in the pathogen.
View Article and Find Full Text PDFMol Plant Microbe Interact
May 2010
Scab caused by the pathogen Venturia inaequalis is considered the most important fungal disease of cultivated apple (Malus x domestica Borkh.). In all, 16 monogenic resistances against scab have been found in different Malus spp.
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