scholarly journals Genetic Structure of the Phytophthora infestans Population in Morocco

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 173-176 ◽  
Author(s):  
M. Sedegui ◽  
R. B. Carroll ◽  
A. L. Morehart ◽  
T. A. Evans ◽  
S. H. Kim ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Late Blight ◽  
Sexual Reproduction ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Potato Seed ◽  
Mating Types ◽  
Potato Field ◽  
New Genotype

ABSRACT In 1996 to 1998, a late-blight survey was conducted in potato- and tomato-growing regions of Morocco. A total of 149 isolates of Phytophthora infestans were collected and analyzed for the glucose-6-phosphate isomerase (Gpi) and peptidase (Pep) alleles, mating types, and metalaxyl sensitivities. Four genotypes were identified: MO-1 (mating type A1, Gpi 100/100, Pep 92/100), MO-2 (mating type A1, Gpi 86/100, Pep 92/100), MO-3 (mating type A2 Gpi 100/100, Pep 100/100), and MO-4 (mating type A1, Gpi 100/100, Pep 100/100). The potato isolates were MO-1 (1996 & 97), MO-3 (1998), and MO-4 (1998). The frequencies of A1 (MO-4) and A2 (MO-3) mating types in potato fields in 1998 were 26 and 74%, respectively. Potato isolates were pathogenic to both potatoes and tomatoes. The isolates collected from tomatoes in 1997 and 1998 were MO-2. Potato and tomato isolates were insensitive and sensitive to metalaxyl, respectively. The change of genotype population in 1998 was probably caused by migration of a new genotype from Europe associated with importation of potato seed. The detection of A1 and A2 mating types in the same potato field indicates the potential for sexual reproduction of P. infestans in Morocco.

scholarly journals Population Structure of the Late Blight Pathogen Phytophthora infestans in a Potato Germplasm Nursery in Two Consecutive Years

2015 ◽  
Vol 105 (6) ◽  
pp. 771-777 ◽  
Author(s):  
Yuee Tian ◽  
Junliang Yin ◽  
Jieping Sun ◽  
Hongmei Ma ◽  
Yunfang Ma ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Plant Pathogens ◽  
Control Strategies ◽  
Northwestern China ◽  
Potato Seed ◽  
Low Level ◽  
Potato Germplasm

As the causal agent of late blight on potato, Phytophthora infestans is one of the most destructive plant pathogens worldwide and widely known as the Irish potato famine pathogen. Understanding the genetic structure of P. infestans populations is important both for breeding and deployment of resistant varieties and for development of disease control strategies. Here, we investigate the population genetic structure of P. infestans in a potato germplasm nursery in northwestern China. In total, 279 isolates were recovered from 63 potato varieties or lines in 2010 and 2011, and were genotyped by mitochondrial DNA haplotypes and a set of nine simple-sequence repeat markers. Selected isolates were further examined for virulence on a set of differential lines containing each resistance (R) gene (R1 to R11). The overall P. infestans population was characterized as having a low level of genetic diversity and resistance to metalaxyl, and containing a high percentage of individuals that virulent to all 11 R genes. Both A1 and A2 mating types as well as self-fertile P. infestans isolates were present but there was no evidence of sexual reproduction. The low level of genetic differentiation in P. infestans populations is probably due to the action of relatively high levels of migration as supported by analysis of molecular variance (P < 0.01). Migration and asexual reproduction were the predominant mechanisms influencing the P. infestans population structure in the germplasm nursery. Therefore, it is important to ensure the production of pathogen-free potato seed tubers to aid sustainable production of potato in northwestern China.

scholarly journals Genetic Change Within Populations of Phytophthora infestans in the United States and Canada During 1994 to 1996: Role of Migration and Recombination

1998 ◽  
Vol 88 (9) ◽  
pp. 939-949 ◽  
Author(s):  
Stephen B. Goodwin ◽  
Christine D. Smart ◽  
Robert W. Sandrock ◽  
Kenneth L. Deahl ◽  
Zamir K. Punja ◽  
...  
Keyword(s):  
United States ◽  
Sexual Reproduction ◽  
Phytophthora Infestans ◽  
High Sensitivity ◽  
The United States ◽  
Rapid Identification ◽  
Mating Types ◽  
Long Distance ◽  
New Genotype ◽  
The Us

Dramatic changes occurred within populations of Phytophthora infestans in the United States and Canada from 1994 through 1996. Occurrence of the US-8 genotype, detected rarely during 1992 and 1993, increased rapidly and predominated in most regions during 1994 through 1996. US-7, which infected both potato and tomato and made up almost 50% of the sample during 1993, was detected only rarely among 330 isolates from the United States analyzed during 1994. It was not detected at all in more limited samples from 1996. Thus, ability to infect both potato and tomato apparently did not increase the fitness of this genotype relative to US-8, as predicted previously. US-1, the previously dominant genotype throughout the United States and Canada, made up 8% or less of the samples analyzed during 1994 through 1996. A few additional genotypes were detected, which could indicate the beginnings of sexual reproduction of P. infestans within the United States and Canada. However, clonal reproduction still predominated in all locations sampled; opportunities for sexual reproduction probably were limited, because the A1 and A2 mating types usually were separated geographically. The high sensitivity of the US-1 genotype to the fungicide metalaxyl also could have reduced opportunities for contact between the mating types in fields where this compound was applied. The previous correlation between metalaxyl sensitivity and genotype was confirmed and extended to a new genotype, US-17: all US-1 isolates tested were sensitive; all isolates of the US-7, US-8, and US-17 genotypes tested to date have been resistant. Isolates of P. capsici and P. erythroseptica, two other species often found on tomato and potato, could be easily distinguished from each other and from P. infestans using a simple allozyme assay for the enzyme glucose-6-phosphate isomerase. This technique could be useful for rapid identification of species, in addition to genotype of P. infestans. It generally was not possible to predict which genotypes would be present in a location from 1 year to the next. Long-distance movement of US-8 in seed tubers was documented, and this was probably the primary means for the rapid spread of this genotype from 1993 through 1996.

scholarly journals Significance of Sexual Reproduction of Phytophthora infestans in the Czech Republic

2018 ◽  
Vol 66 (5) ◽  
pp. 1191-1197
Author(s):  
Jana Mazáková ◽  
Miloslav Zouhar ◽  
Pavel Ryšánek
Keyword(s):  
Czech Republic ◽  
Late Blight ◽  
Sexual Reproduction ◽  
Phytophthora Infestans ◽  
Growing Season ◽  
Field Conditions ◽  
Effect Of Temperature ◽  
Mating Types ◽  
The Czech Republic ◽  
Leaf Discs

A total of 187 naturally late blight‑diseased potato leaves were sampled from 31 sites and five regions of the Czech Republic during the growing season in 2012–2014 and 2016 and examined microscopically for the ability of Phytophthora infestans to produce oospores in infected leaves under field conditions. Although the occurrence of the A1 and A2 mating types required for sexual reproduction of P. infestans was previously confirmed in the Czech Republic, no oospores were detected in this study. To study the effect of temperature on the survival of oospores produced from crosses of three pairs of P. infestans isolates, oospores in leaf discs and agar were exposed to temperatures ranging from –24 to 10 °C and then evaluated for viability with the plasmolysis test. Oospore viability ranged from 13.02 to 63.90 % and from 7.77 to 63.37 % for oospores produced in agar and leaf discs, respectively, with the highest frequencies of viable oospores occurring at 4 and 10 °C. To determine whether oospores may survive under field conditions, agar plates with oospores were buried in soil in Prague‑Suchdol and Svitavy for seven months during the overwintering period (October–May) in 2011–2015. There were statistically significant differences in oospore viability examined by the plasmolysis test between the localities, and oospore viability ranged from 29 to 43 % and from 15 to 44 % in Prague‑Suchdol and Svitavy, respectively.

An improved PCR method for rapid and accurate identification of mating types in the late blight pathogen Phytophthora infestans

2021 ◽  
Author(s):  
Romain Mabon ◽  
Michèle Guibert ◽  
Roselyne Corbiere ◽  
Didier Andrivon
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Multiplex Pcr ◽  
Mating Type ◽  
Mating Types ◽  
Accurate Identification ◽  
Fta Cards ◽  
Multiplex Pcr Assay ◽  
Freeze Dried ◽  
Late Blight Pathogen

Mating type is a critical trait in heterothallic organisms. In plant pathogenic oomycetes, like the late blight pathogen Phytophthora infestans, it is usually identified through pairing between tester and candidate isolates, a method which is both laborious and applicable to live isolates only. Therefore, developing simple and fast PCR tests to reliably identify P. infestans mating types is of great interest for population genetic studies. A multiplex PCR assay combining the amplification of a locus diagnostic for P. infestans and of one diagnostic for the A1 mating type was developed and validated on a collection of 1441 samples, covering the current and past diversity of European P. infestans populations. These samples obtained from either freeze-dried mycelium or from FTA cards on which diseased leaflets had been pressed. The multiplex assay correctly identified mating types in 97.4 % of these samples. The main source of incorrect assignment was the lack of amplification of the A1 diagnostic allele, due to insufficient DNA quality and/or quantity in the reaction mix. This multiplex PCR, applicable to both live and stored material, thus constitutes a useful addition to the set of molecular tools available for population typing in P. infestans.

scholarly journals First Report of A1 and A2 Mating Types of Phytophthora infestans on Potato and Tomato in Nepal

Plant Disease ◽  
1998 ◽  
Vol 82 (9) ◽  
pp. 1064-1064 ◽  
Author(s):  
S. K. Shrestha ◽  
K. Shrestha ◽  
K. Kobayashi ◽  
N. Kondo ◽  
R. Nishimura ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Simultaneous Occurrence ◽  
Mating Types ◽  
Isozyme Loci ◽  
Oospore Formation ◽  
The Hill ◽  
Pathogenic Diversity ◽  
Important Disease

Late blight caused by Phytophthora infestans (Mont.) de Bary is an important disease of potato and tomato that occurs annually in the hills and occasionally in the terai (plain) of Nepal. In 1996 and 1997, each year, 50 samples of late blight-infected potato and tomato leaves were collected from the hill and terai areas. The pathogen was cultured on Rye A agar. Each isolate was paired on clear V8 agar with reference isolates DN111 (A1 mating type) and DN107 (A2 mating type) received from Hokkaido University, Japan, and examined for oospore formation after 10 to 15 days of incubation at 20°C. The proportion of A2 isolates was 6% in 1996 and 42% in 1997. The A2 isolates were mainly from the high hills (2,000 to 2,500 m) where local and Andean types of potatoes are grown. Analysis of genotypes of isolates at the glucosephosphate isomerase (GPI-1), malic enzyme (ME), and peptidase (PEP-1) (1,2) isozyme loci revealed genetic diversity between A1 and A2 isolates. A1 isolates from potato were either homozygous (100/100) or heterozygous (86/100) for GPI-1, whereas all A1 isolates from tomato were heterozygous (86/100). All A1 isolates were homozygous (100/100) at the ME locus and heterozygous (92/100) at the PEP-1 locus. A2 isolates were homozygous (100/100) at all isozyme loci. The results show that both A1 and A2 mating types of P. infestans are present in Nepal, and that they display different isozyme genotypes. It is speculated that the A1 type may have migrated with potatoes from Europe while the A2 type may have been introduced with Andean potatoes from Latin America more recently. The simultaneous occurrence of both mating types may allow the fungus to increase its pathogenic diversity and to survive by means of oospores. References: (1) A. A. Mosa et al. Plant Pathol. 42:26, 1993. (2) P. W. Tooley et al. J. Hered. 76:431, 1985.

scholarly journals Genetic Composition of Phytophthora infestans in Canada Reveals Migration and Increased Diversity

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1729-1735 ◽  
Author(s):  
Melanie L. Kalischuk ◽  
Khalil I. Al-Mughrabi ◽  
Rick D. Peters ◽  
Ron J. Howard ◽  
H. W. (Bud) Platt ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Phytophthora Infestans ◽  
Prince Edward Island ◽  
Weather Conditions ◽  
The United States ◽  
Potato Seed ◽  
Polymorphism Analysis ◽  
Mating Types ◽  
Long Distance ◽  
Canadian Provinces

A dramatic increase in the incidence of late blight and changes within populations of Phytophthora infestans have been observed in various regions of Canada. In this study, the occurrence of several new genotypes of the pathogen was documented with associated phenotypes that dominated pathogen populations. Genotype US-23, previously detected only among isolates from the United States, dominated in the western Canadian provinces of British Columbia, Alberta (AB), Saskatchewan, and Manitoba (MB). Although isolates of US-23 infect both potato and tomato, these isolates were the only genotype recovered from commercial garden centers in Canada. Isolates of genotype US-8, previously dominant throughout Canada, represented the only genotype detected from the eastern Canadian provinces of New Brunswick and Prince Edward Island. Isolates of other genotypes detected in Canada included US-11 in AB, US-24 in MB, and US-22 in Ontario (ON). An additional genotype was detected in ON which appears to be a derivative of US-22 that may have arisen through sexual reproduction. However, evidence of clonal reproduction dominated among the isolates collected, and opportunities for sexual reproduction were probably limited because of a surprising geographic separation of the A1 and A2 mating types in Canada. Sensitivity of the US-22, US-23, and US-24 isolates to the fungicide metalaxyl, movement of potato seed and transplants, and weather conditions may have contributed to reduced opportunities for contact between the mating types in fields in Canada. All P. infestans isolates were readily distinguished from other related oomycetes with RG57 restriction fragment length polymorphism analysis. Long-distance movement in seed tubers and garden center transplants may have contributed to the rapid spread of the P. infestans genotypes across Canada. Tracking pathogen movement and population composition should improve the ability to predict the genotypes expected each year in different regions of Canada.

scholarly journals Complete mitogenome mapping of potato late blight pathogen, Phytophthora infestans A2 mating type

2017 ◽  
Vol 2 (1) ◽  
pp. 90-91
Author(s):  
Virupaksh U. Patil ◽  
G. Vanishree ◽  
Debasis Pattanayak ◽  
Sanjeev Sharma ◽  
Vinay Bhardwaj ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Potato Late Blight ◽  
Complete Mitogenome ◽  
Late Blight Pathogen

scholarly journals Phenotypic Characterization of Recent Clonal Lineages of Phytophthora infestans in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 873-881 ◽  
Author(s):  
G. Danies ◽  
I. M. Small ◽  
K. Myers ◽  
R. Childers ◽  
W. E. Fry
Keyword(s):  
United States ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
The United States ◽  
Phenotypic Characterization ◽  
Phenotypic Traits ◽  
Mating Types ◽  
Late Blight Disease ◽  
Blight Disease

Phytophthora infestans, the causal agent of late blight disease, has been reported in the United States and Canada since the mid-nineteenth century. Due to the lack of or very limited sexual reproduction, the populations of P. infestans in the United States are primarily reproducing asexually and, thus, show a simple genetic structure. The emergence of new clonal lineages of P. infestans (US-22, US-23, and US-24) responsible for the late blight epidemics in the northeastern region of the United States in the summers of 2009 and 2010 stimulated an investigation into phenotypic traits associated with these genotypes. Mating type, differences in sensitivity to mefenoxam, differences in pathogenicity on potato and tomato, and differences in rate of germination were studied for clonal lineages US-8, US-22, US-23, and US-24. Both A1 and A2 mating types were detected. Lineages US-22, US-23, and US-24 were generally sensitive to mefenoxam while US-8 was resistant. US-8 and US-24 were primarily pathogenic on potato while US-22 and US-23 were pathogenic on both potato and tomato. Indirect germination was favored at lower temperatures (5 and 10°C) whereas direct germination, though uncommon, was favored at higher temperatures (20 and 25°C). Sporangia of US-24 released zoospores more rapidly than did sporangia of US-22 and US-23. The association of characteristic phenotypic traits with genotype enables the prediction of phenotypic traits from rapid genotypic analyses for improved disease management.

Identification of biosynthetic intermediates for the mating hormone α2 of the plant pathogen Phytophthora

2021 ◽  
Author(s):  
Suguru Ariyoshi ◽  
Yusuke Imazu ◽  
Ryuji Ohguri ◽  
Ryo Katsuta ◽  
Arata Yajima ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Sexual Reproduction ◽  
Mating Type ◽  
Plant Pathogen ◽  
Type Strain ◽  
Mating Types ◽  
Synthetic Intermediates ◽  
The Cross

Abstract The heterothallic group of the plant pathogen Phytophthora can sexually reproduce between the cross-compatible mating types A1 and A2. The mating hormone α2, produced by A2 mating type and utilized to promote the sexual reproduction of the partner A1 type, is known to be biosynthesized from phytol. In this study, we identified two biosynthetic intermediates, 11- and 16-hydroxyphytols (1 and 2), for α2 by administering the synthetic intermediates to an A2 type strain to produce α2 and by administering phytol to A2 strains to detect the intermediates in the mycelia. The results suggest that α2 is biosynthesized by possibly two cytochrome P450 oxygenases via two hydroxyphytol intermediates (1 and 2) in A2 hyphae and secreted outside.

scholarly journals Phytophthora infestans Mating Types on Tomato (Solanum lycopersicum) in Southern Spain

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 109-109 ◽  
Author(s):  
J. M. Segura ◽  
M. de Cara ◽  
M. Santos ◽  
J. Tello
Keyword(s):  
Phytophthora Infestans ◽  
Mating Type ◽  
Agar Medium ◽  
The Other ◽  
Southern Spain ◽  
White Mold ◽  
Mating Types ◽  
Tomato Plants ◽  
Cornell University ◽  
Tomato Seeds

During 2004, an unusual spread of Phytophthora infestans on tomato plants in greenhouses located in Almería and Granada provinces, southern Spain, was observed. Infected plants had water-soaked, brown spots on leaves and stems and necrotic areas with white mold on the surface of fruits. Three isolates were obtained by plating diseased tissue on V8 juice agar medium and maintained on rye agar at 18°C. These isolates were analyzed for the mating type. Crosses were carried out using V8 juice agar and rye agar. The two parental isolates US1 (A1) and US8 (A2) were both provided by W. E. Fry, Cornell University, Ithaca, NY. Two of the Spanish isolates were homothallic and the other isolate belonged to the uncommon mating type A1A2. To confirm the occurrence of the two mating types, 43 single-sporangium progeny were produced and analyzed from the A1A2 mating type. Thirty eight isolates were A1, two were A2, one was A1A2 mating type, and two were sterile. Assessment of five single-sporangium progeny from the homothallic type resulted in two A1, two homothallic, and one sterile isolate. A1A2 isolates produced oospores when crossed with either A1 or A2, but not when self-crossed. Previously, the A1A2 mating type has been found in Israel in the field and was obtained from oospores produced on tomato seeds (2,3). Since 2003, mating types of P. infestans isolates recovered from potato (60) and tomato (8) in southern Spain have been characterized. Seventy-five percent of the isolates recovered from potato were A1 and 25% were A2 mating types. Isolates recovered from tomato were 50% A1 and 50% A2 (1). To our knowledge, this is the first report of the occurrence of the A1A2 mating type and homothallic P. infestans isolates on tomato in Spain. References: (1) E. Andujar et al. Congr. Sociedad Española de Fitopatol. 12:244, 2004. (2) E. Rubin and Y. Cohen. Phytoparasitica 32:237, 2004. (3) E. Rubin and Y. Cohen. Plant Dis. 90:741, 2006.

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