Role of Solanum dulcamara L. in Potato Late Blight Epidemiology
Golas, T.M. ; Weerden, G.M. van der; Berg, R.G. van den; Mariani, C. ; Allefs, J.J.H.M. - \ 2010
Potato Research 53 (2010)1. - ISSN 0014-3065 - p. 69 - 81.
infestans mont debary - nevado-de-toluca - phytophthora-infestans - natural occurrence - solanaceous hosts - western slopes - resistance - plant - inoculation - strains
Four sites with naturally growing Solanum dulcamara were surveyed during 2006 and 2007 for the presence of late blight. Despite 2 years of observations, no late blight was detected among natural populations of bittersweet. Nevertheless, repeated infections occurred on few S. dulcamara plants from a collection growing in a botanical garden in the same years. These plants were used to investigate the possibility of survival of the inoculum between seasons. In the respective years, a set of 21 and 52 S. dulcamara accessions inoculated with Phytophthora infestans under field conditions resulted in a wide range of responses to the disease. More susceptible reactions were found among genotypes collected at greater distance from commercial potato fields indicating the possibility of genetic selection caused by P. infestans. However, both scarceness of natural infections and no overwintering, suggest that bittersweet may not play a role in late blight epidemiology
Phytophthora infestans isolates lacking class I ipiO variants are virulent on Rpi-blb1 potato
Champouret, N. ; Bouwmeester, K. ; Rietman, H. ; Lee, T. van der; Maliepaard, C.A. ; Heupink, A. ; Vondervoort, P.J.I. van de; Jacobsen, E. ; Visser, R.G.F. ; Vossen, E.A.G. van der; Govers, F. ; Vleeshouwers, V.G.A.A. - \ 2009
Molecular Plant-Microbe Interactions 22 (2009)12. - ISSN 0894-0282 - p. 1535 - 1545.
late blight resistance - mediated plant transformation - broad-spectrum resistance - nevado-de-toluca - solanum-bulbocastanum - central mexico - downy mildew - cell-death - population-structure - cultivated potato
A strategy to control the devastating late blight disease is providing potato cultivars with genes that are effective in resistance to a broad spectrum of Phytophthora infestans isolates. Thus far, most late blight resistance (R) genes that were introgressed in potato were quickly defeated. In contrast, the Rpi-blb1 gene originating from Solanum bulbocastanum has performed as an exclusive broad-spectrum R gene for many years. Recently, the RXLR effector family ipiO was identified to contain Avr-blb1. Monitoring the genetic diversity of the ipiO family in a large set of isolates of P. infestans and related species resulted in 16 ipiO variants in three distinct classes. Class I and class II but not class III ipiO variants induce cell death when coinfiltrated with Rpi-blb1 in Nicotiana benthamiana. Class I is highly diverse and is represented in all analyzed P. infestans isolates except two Mexican P. infestans isolates, and these were found virulent on Rpi-blb1 plants. In its C-terminal domain, IPI-O contains a W motif that is essential for triggering Rpi-blb1-mediated cell death and is under positive selection. This study shows that profiling the variation of Avr-blb1 within a P. infestans population is instrumental for predicting the effectiveness of Rpi-blb1-mediated resistance in potato.
The biology of Phytophthora infestans at its center of origin
Grünwald, N.J. ; Flier, W.G. - \ 2005
Annual Review of Phytopathology 43 (2005). - ISSN 0066-4286 - p. 171 - 190.
potato late-blight - nevado-de-toluca - germplasm collecting expedition - broad-spectrum resistance - solanum-bulbocastanum - central mexico - western slopes - mont debary - interspecific hybridization - genetic differentiation
The central highlands of Mexico are considered to be a center of genetic diversity for both the potato late blight pathogen and for tuber-bearing Solanum spp. Recent work conducted in Mexico and South America sheds new light on the biology and evolution of Phytophthora infestans and other related Phytophthora pathogens. It now appears that Mexican Solanum species, which coevolved with P. infestans and were previously known for providing a source of R-genes, also provide a source of quantitative, rate-reducing resistance that is highly effective, stable, and durable. It is now apparent that Mexico is the center of origin not only of the potato late blight pathogen P. infestans, but also of several related Phytophthora species including P. mirabilis, P. ipomoeae, and possibly P. phaseoli. We close with the hypothesis that these Phytophthora species evolved sympatrically from one ancestral host through adaptive radiation onto their respective four host families
The population structure of Phytophthora infestans from the Toluca Valley of Central Mexico suggests genetic differentiation between populations from cultivated potato and wild Solanum spp.
Flier, W.G. ; Grünwald, N.J. ; Kroon, L.P.N.M. ; Sturbaum, A.K. ; Bosch, G.B.M. van den; Garay-Serrano, E. ; Lozoya-Saldaña, H. ; Fry, W.E. ; Turkensteen, L.J. - \ 2003
Phytopathology 93 (2003)4. - ISSN 0031-949X - p. 382 - 390.
nevado-de-toluca - western slopes - mont debary - sympatric speciation - pcr amplification - p-infestans - flow - resistance - diversity - oospores
The Population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected front cultivated potatoes and the native wild Solanum spp., S. demissum and S. xedinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplified fragment length polymorphism (AFLP) multi-locus fingerprint genotype. Isolate samples were monomorphic for mtDNA haplotype because all isolates tested were of the la haplotype. A total of 158 multilocus AFLP genotypes were identified among the 170 P. infestans isolates included in this study. P. infestans populations sampled in the Toluca Valley in 1997 were highly variable and almost every single isolate represented a unique genotype based on the analysis of 165 AFLP marker loci. Populations of P infestans collected from the commercial potato-growing region in the valley, the subsistence potato production area along the slopes of the Nevado de Toluca, and the native Solanum spp. on the forested slopes of the volcano showed a high degree of genetic diversity. The number of polymorphic loci varied from 20.0 to 62.4% for isolates collected from the field station and wild Solanum spp. On average, 81.8% (135) of the AFLP loci were polymorphic. Heterozygosity varied between 7.7 and 19.4%. Significant differentiation was found at the population level between strains originating from cultivated potatoes and wild Solanum spp. (P = 0.001 to 0.022). Private alleles were observed in individual isolates collected from all three populations, with numbers of unique dominant alleles varying from 9 to 16 for isolates collected from commercial potato crops and native Solanum spp.. respectively. Four AFLP markets were exclusively found present in isolates collected from S. demissum. Indirect estimation of gene flow between populations indicated restricted gene flow between both P. infestans populations front cultivated potatoes and wild Solanum hosts. There was no evidence found for the presence of substructuring at the subpopulation (field) level. We hypothesize that population differentiation and genetic isolation of P infestans in the Toluca Valley is driven by host-specific factors (i.e., R-genes) widely distributed in wild Solanum spp. and random genetic drift.
Population structure of Phytophthora infestans in the Toluca Valley region of Central Mexico
Grünwald, N.J. ; Flier, W.G. ; Sturbaum, A.K. ; Garay-Serrano, E. ; Bosch, G.B.M. van den; Smart, C.D. ; Matuszak, J.M. ; Turkensteen, L.J. ; Fry, W.E. - \ 2001
Phytopathology 91 (2001)9. - ISSN 0031-949X - p. 882 - 890.
nevado-de-toluca - mating-type loci - western slopes - mont debary - diversity - solanum - differentiation - segregation - variability - resistance
We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii) modern cultivars in high-input agriculture (VALLEY). Isolates were sampled in 1988-89 (n= 179) and in 1997-98 (n= 389). In both sampling periods, the greatest genetic diversity was observed in RURAL and VALLEY habitats. Based on the Glucose-6-phosphate isomerase and Peptidase allozymes, the subpopulations from the three habitats were significantly differentiated in both sampling periods. In contrast to allozyme data for 1997-98, no differences were found among the three subpopulations for sensitivity to metalaxyl. Two groups of isolates identical for allozyme and mating type were further investigated by restriction fragment length polymorphism fingerprinting; 65% of one group and 85% of another group were demonstrated to be unique. The genetic diversity data and the chronology of disease occurrence during the season are consistent with the hypothesis that populations of P. infestans on wild Solanum populations are derived from populations on cultivated potatoes in the central highlands of Mexico near Toluca.