Potato cyst nematodes (PCN) collected in six localities in the Leningrad region of North West Russia were identified as Globodera rostochiensis pathotype Ro1 and were used for subsequent resistance tests. Seventynine accessions of cultivated and closely related wild potato species from the VIR collection in Russia were screened on resistance to G. rostochiensis pathotype Ro1 and on the presence of molecular markers for H1 and Gro1-4 resistance genes. No associations were detected between the resistance level of diploid and tetraploid Andean and tetraploid Chilean potato landraces (indigenous cultivars) and their related wild species and their geographical distribution or presence of PCR-based markers that are associated with the H1 and Gro1-4 genes. At the same time, all susceptible genotypes lacked such markers. New sources of resistance were found and could be used in breeding.
Potato late blight, caused by the oomycete phytopathogen Phytophthora infestans, is a devastating disease found in potato-growing regions worldwide. Long-term management strategies to control late blight include the incorporation of host resistance to predominant strains. However, due to rapid genetic changes within pathogen populations, rapid and recurring identification and integration of novel host resistance traits is necessary. Wild relatives of potato offer a rich source of desirable traits, including late blight resistance, but screening methods can be time intensive. We tested the ability of taxonomy, ploidy, crossing group, breeding system, and geography to predict the presence of foliar and tuber late blight resistance in wild Solanum spp. Significant variation for resistance to both tuber and foliar late blight was found within and among species but there was no discernable predictive power based on taxonomic series, clade, ploidy, breeding system, elevation, or geographic location. We observed a moderate but significant correlation between tuber and foliar resistance within species. Although previously uncharacterized sources of both foliar and tuber resistance were identified, our study does not support an assumption that taxonomic or geographic data can be used to predict sources of late blight resistance in wild Solanum spp.
BackgroundThe characterization of major resistance genes (R genes) in the potato remains an important task for molecular breeding. However, R genes are rapidly evolving and frequently occur in genomes as clusters with complex structures, and their precise mapping and identification are complicated and time consuming.ResultsComparative analysis of root transcriptomes of Solanum phureja genotypes with contrasting resistance to Globodera rostochiensis revealed a number of differentially expressed genes. However, compiling a list of candidate R genes for further segregation analysis was hampered by their scarce annotation. Nevertheless, combination of transcriptomic analysis with data on predicted potato NBS-LRR-encoding genes considerably improved the quality of the results and provided a reasonable number of candidate genes that provide S. phureja with strong resistance to the potato golden cyst nematode.ConclusionCombination of comparative analyses of tissue-specific transcriptomes in resistant and susceptible genotypes may be used as an approach for the rapid identification of candidate potato R genes for co-segregation analysis and may be used in parallel with more sophisticated studies based on genome resequencing.Electronic supplementary materialThe online version of this article (10.1186/s12870-017-1193-1) contains supplementary material, which is available to authorized users.
With 7 figures and 1 table
Abstract
The causal agent of potato wart (Synchytrium endobioticum) is an obligate parasitic chytrid fungus. It is included as a quarantine pathogen in 55 countries, with losses in susceptible cultivars reaching 50–100%. The aim of our study was to characterize the resistance to S. endobioticum pathotype 1 in cultivated potatoes from a well‐characterized subset of the Vavilov Institute of Plant Industry collection and to determine whether this resistance is associated with cultivated potato species taxonomy, with ploidy, with geographic distance or with a molecular marker Nl25‐1400 proposed for molecular screening for resistance to pathotype 1 of S. endobioticum. Within the diversity of 52 landrace genotypes, our work shows a lack of such predictive associations with wart resistance. High intraspecific variation of wart diseases resistance allows the selection of extremely resistant and susceptible genotypes available for future genetic and breeding studies.
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.