Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
Alternaria heart rot of pomegranate fruit is generally considered a minor disease. However, the current listing of the causal pathogen in California as “Alternaria sp.” or as “A. alternata and other Alternaria spp.” restricts trade of the crop to some major export markets where quarantines are in place in an effort to prevent the spread of unknown or undescribed pathogens. Thus, species identification of the pathogen is critical in determining whether infected fruit should be regulated by quarantines. In this study, 86 isolates of Alternaria were collected from pomegranate fruit with Alternaria heart rot symptoms from major production areas in California. An unweighted pair group method with arithmetic means analysis based on amplified fragment length polymorphisms revealed two main clusters, each with a high degree of variability. One of the clusters contained 24 isolates from pomegranate and one reference isolate of Alternaria arborescens. Reference isolates of A. alternata and A. tenuissima were found among pomegranate isolates in the other cluster, and these two species could not be separated. In maximum-parsimony analysis of ribosomal DNA internal transcribed spacer sequence data, representative pomegranate isolates all clustered with reference sequences of species in section Alternaria. Single-nucleotide differences separated A. arborescens, A. gaisen, and two pomegranate isolates from the majority of the remaining isolates. Sequence comparisons of gapdh and OPA10-2 loci indicated that none of the pomegranate isolates were identical to A. gaisen, which is a quarantine pathogen. Due to high genetic similarity and variability of morphological characteristics, revisions of the taxonomy of small-spored Alternaria spp. have been proposed by others. Based on this recent taxonomic work and work herein by us, pomegranate isolates from California can be assigned to A. alternata and A. arborescens. Reassessment of export restrictions for California pomegranate due to the previous pathogen classification is warranted. Fruit injection inoculations with conidia of 12 representative isolates 3 months before harvest caused typical symptoms of Alternaria heart rot, whereas flower inoculations did not result in fruit disease.
Alternaria heart rot of pomegranate fruit is generally considered a minor disease. However, the current listing of the causal pathogen in California as “Alternaria sp.” or as “A. alternata and other Alternaria spp.” restricts trade of the crop to some major export markets where quarantines are in place in an effort to prevent the spread of unknown or undescribed pathogens. Thus, species identification of the pathogen is critical in determining whether infected fruit should be regulated by quarantines. In this study, 86 isolates of Alternaria were collected from pomegranate fruit with Alternaria heart rot symptoms from major production areas in California. An unweighted pair group method with arithmetic means analysis based on amplified fragment length polymorphisms revealed two main clusters, each with a high degree of variability. One of the clusters contained 24 isolates from pomegranate and one reference isolate of Alternaria arborescens. Reference isolates of A. alternata and A. tenuissima were found among pomegranate isolates in the other cluster, and these two species could not be separated. In maximum-parsimony analysis of ribosomal DNA internal transcribed spacer sequence data, representative pomegranate isolates all clustered with reference sequences of species in section Alternaria. Single-nucleotide differences separated A. arborescens, A. gaisen, and two pomegranate isolates from the majority of the remaining isolates. Sequence comparisons of gapdh and OPA10-2 loci indicated that none of the pomegranate isolates were identical to A. gaisen, which is a quarantine pathogen. Due to high genetic similarity and variability of morphological characteristics, revisions of the taxonomy of small-spored Alternaria spp. have been proposed by others. Based on this recent taxonomic work and work herein by us, pomegranate isolates from California can be assigned to A. alternata and A. arborescens. Reassessment of export restrictions for California pomegranate due to the previous pathogen classification is warranted. Fruit injection inoculations with conidia of 12 representative isolates 3 months before harvest caused typical symptoms of Alternaria heart rot, whereas flower inoculations did not result in fruit disease.
Pomegranates were one of the first domesticated fruit crops, and their long history resulted in the development of local cultivars all over the world. Spain is one of the main producers and exporters of this crop in the Mediterranean Basin, but in order to maintain the competitiveness of this crop, new varieties should be developed. For this purpose, the pomegranate germplasm collection hold at the Agricultural Experiment Station of Elche, a public institution dependent on the Valencian regional government, is an interesting tool. However, the detailed characterization of any germplasm collection is a fundamental requirement to be able to make the most of these resources, allowing to identify putative promising accessions and to optimize the design of the future crosses. In this work, the genetic diversity of 94 accessions of this collection was analyzed using 19 microsatellite markers. As a result, 85 different genotypes were identified. These genetic profiles could be useful for varietal identification. Despite this genetic diversity, no clear substructure was observed, except for the ornamental accessions, that could be related to the vegetative propagation of the species. Additionally, the morphological characterization of this collection has made it possible to identify some materials that may be of interest as a source of traits for breeding. Results presented here pave the way for further genetic analyses, allowing the selection of parents to obtain segregating populations, as well as their descendants by the use of molecular assisted selection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.