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 Sprinkling Irrigation Enhances Production of Oospores of Phytophthora Infestans in Field-Grown Crops of Potato

2000 ◽  
Vol 90 (10) ◽  
pp. 1105-1111 ◽  
Author(s):  
Yigal Cohen ◽  
Sonja Farkash ◽  
Alexander Baider ◽  
David S. Shaw
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Field Experiments ◽  
Soil Surface ◽  
Field Trials ◽  
Detached Leaves ◽  
Oospore Formation ◽  
Potato Crops ◽  
Host Tissues

Two field experiments were conducted to study the effect of overhead sprinkling irrigation on oospore formation by the late blight fungus Phytophthora infestans in potato. Total rain (natural + sprinkling) accumulated in treatments of experiment 1 (winter 1997 to 1998) were 765, 287, and 219 mm and treatments of experiment 2 (winter 1999 to 2000) were 641, 193, and 129 mm. Sporangia from 11 isolates of P. infestans were combined in eight pairs, seven of A1 and A2 and one of A2 and A2 mating type, and were sprayed on field-grown potato crops (42 plants per plot at 7 m2 each) and examined for their ability to form oospores in the host tissues. In experiment 1, oospores were recorded in a total of 132 of 1,680 leaflets (7.9%), 24 of 105 stems, and 2 of 90 tubers. In experiment 2, oospores were recorded in 40 of 519 leaflets (7.7%), but not in any of the 90 stems or the 45 tubers examined. Both the proportion of leaflets containing oospores and the number of oospores per leaflet increased with time after inoculation and were dependent on the rain regime, the position of leaves on the plant, and the isolate pair combination. In both field trials, increasing the rainfall significantly enhanced oospore production in leaves. Leaf samples collected from the soil surface had significantly more oospores than those collected from the midcanopy. Two pairs in experiment 1 were more fertile than the others, whereas the pair used in experiment 2 was the least fertile. The total number of oospores per leaflet usually ranged from 10 to 100 in experiment 1, but only from 2 to 10 in experiment 2. Maximal oospore counts in the field were 200 and 50 in experiments 1 and 2, respectively, but ranged from ≈2,000 to 12,000 oospores per leaflet in detached leaves in the laboratory. We concluded that P. infestans can produce oospores in the foliage of field-grown potato crops, especially when kept wet by regular overhead sprinkling irrigation, but production was far below that in the laboratory.

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 First Report of Solanum physalifolium as a Host Plant for Phytophthora infestans in Sweden

Plant Disease ◽  
2003 ◽  
Vol 87 (12) ◽  
pp. 1538-1538 ◽  
Author(s):  
B. Andersson ◽  
M. Johansson ◽  
B. Jönsson
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Host Plant ◽  
Mating Type ◽  
Early Summer ◽  
Growing Seasons ◽  
Oospore Formation ◽  
Petri Dishes ◽  
Global Threat ◽  
Shape And Size

In the early summer of 2003, lesions resembling those caused by Phytophthora infestans (Mont.) de Bary on potato were observed on Solanum physalifolium Rusby var. nitidibaccatum (Bitter) Edmonds (2) that was growing as a weed in a parsnip (Pastinaca sativa) field in southern Sweden. When infected leaves of S. physalifolium were observed under the microscope (×200 magnification), sporangia with the same shape and size as those of P. infestans were observed. Pieces of infected leaves of S. physalifolium were put under tuber slices of S. tuberosum (cv. Bintje) in petri dishes and kept at 20°C. After 4 days, mycelium grew through the slices and sporulated profusely. The sporangia on the slices were of the same shape and size as those observed on the infected S. physalifolium leaves. In Sweden, the ratio of A1 and A2 mating types of P. infestans is 50:50, and oospores are commonly found in infected potato crops (1), so isolates from S. physalifolium were tested for mating type by growing them together with reference isolates of a known mating type on agar plates. Nine of the tested isolates were A1 mating type and six were A2 mating type. One self-fertile isolate was found. Naturally infected leaves of S. physalifolium were incubated at 20°C at 100% relative humidity so the lesions could coalesce and to facilitate oospore formation. After 5 days, oospores identical to those of P. infestans were observed under the microscope (×200 magnification). Sporangia produced by isolates originating from S. physalifolium and S. tuberosum were harvested, and a suspension containing 104 sporangia per ml from each isolate was prepared. Five leaves each of S. nigrum, S. physalifolium, and S. tuberosum (cv. Bintje), were inoculated with 10 μl of each sporangial suspension. Inoculated leaves were incubated in sealed petri dishes at 15°C. After 4 days, all S. tuberosum leaves were infected. After 7 days, two of five leaves of S. physalifolium inoculated with the S. tuberosum isolate and two of five S. physalifolium leaves inoculated with the isolate from S. physalifolium were infected. All lesions produced sporangia similar to those formed by P. infestans. S. nigrum was not infected by any of the isolates. The ability of S. physalifolium to act as a host plant for P. infestans producing sporangia during the growing season and oospores for survival between growing seasons may increase the problems of controlling late blight in potato in Sweden. References: (1) J. Dahlberg et al. Field survey of oospore formation by Phytophthora infestans. (Poster Abstr.) Pages 134–135 In: Late Blight: Managing the Global Threat. Proc Global Late Blight Conf. Charlotte Lizarraga, ed. Centro Internacional De La Papa, On-line publication, ISBN 929060-215-5, 2002. (2) J. M. Edmonds. Bot. J. Linn. Soc. 92:1, 1986.

scholarly journals Commercial Fungicide Formulations Induce In Vitro Oospore Formation and Phenotypic Change in Mating Type in Phytophthora infestans

2000 ◽  
Vol 90 (11) ◽  
pp. 1201-1208 ◽  
Author(s):  
Carol Trout Groves ◽  
Jean Beagle Ristaino
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Petri Dish ◽  
Phenotypic Change ◽  
Tomato Production ◽  
Wide Range ◽  
Oospore Formation ◽  
Commercial Fungicide

A wide range of commercially formulated fungicides cause in vitro effects on mating behavior in specific isolates of Phytophthora infestans, the causal agent of late blight of potato and tomato. Four isolates of P. infestans representing each of the four common US genotypes, US-1, US-6, US-7, and US-8 and varying in their sensitivity to metalaxyl, were exposed to a variety of fungicides used to control late blight in petri dish assays at concentrations ranging from 1 to 100 μg a.i./ml. Exposure of each of these normally heterothallic single mating type isolates of P. infestans to 9 of the 11 commercial fungicide formulations tested resulted in the formation of oospores after 2 to 4 weeks. The highest numbers of oospores were formed on media amended with Ridomil 2E (metalaxyl) and Ridomil Gold EC (mefenoxam) at 0.1 to 10 μg a.i./ml, averaging as many as 471 and 450 oospores per petri dish, respectively. Several other fungicides including Maneb, Manzate (Mancozeb), Curzate (cymoxanil + mancozeb), and Acrobat MZ (dimethomorph + mancozeb) also induced oospore formation, producing from 0 to 200 oospores per plate at fungicide concentrations from 0.1 to 10 μg a.i./ml. The metalaxyl resistant isolates formed oospores in response to the fungicides more often than the metalaxyl sensitive isolates. No oospores were formed on media amended with Bravo (chlorothalonil) or Tattoo C (chlorothalonil + propamocarb HCl) and these compounds completely suppressed growth of the isolates at 0.1 and 1 μg a.i./ml. Three metalaxyl resistant A2 isolates mated with both A1 and A2 isolates after exposure to the fungicides Ridomil 2E and Ridomil Gold EC. Alterations in mating type expression were also observed in a metalaxyl sensitive A1 isolate after exposure to Benlate (benomyl). Copious amounts of chemicals are applied annually to potato and tomato production areas to control late blight. Our results indicate that a wide range of chemically diverse fungicides can induce normally heterothallic metalaxyl resistant isolates of P. infestans to form oospores in vitro after short exposures to the fungicides.

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 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.

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.

Genetic mapping and non-Mendelian segregation of mating type loci in the oomycete, Phytophthora infestans.

Genetics ◽  
1995 ◽  
Vol 141 (2) ◽  
pp. 503-512 ◽  
Author(s):  
H S Judelson ◽  
L J Spielman ◽  
R C Shattock
Keyword(s):  
Phytophthora Infestans ◽  
Mating Type ◽  
Dna Markers ◽  
Bulked Segregant Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Mating Types ◽  
Mendelian Segregation ◽  
Range Restriction ◽  
Type Locus ◽  
Mating Type Locus

Abstract DNA markers linked to the determinants of mating type in the oomycete, Phytophthora infestans, were identified and used to address the genetic basis of heterothallism in the normally diploid fungus. Thirteen loci linked to the A1 and A2 mating types were initially identified by bulked segregant analysis using random amplified polymorphic DNA markers (RAPDs) and subsequently scored in three crosses polymorphisms (SSCP), cleaved amplified polymorphisms (CAPS), or allele-specific polymerase chain reaction markers (AS-PCR). All DNA markers mapped to a single region, consistent with a single locus determining both mating types. Long-range restriction mapping also demonstrated the linkage of the markers to one region and delimited the mating type locus to a 100-kb region. The interval containing the mating type locus displayed non-Mendelian segregation as only two of the four expected genotypes were detected in progeny. This is consistent with a system of balance lethal loci near the mating type locus. A model for mating type determination is presented in which the balanced lethals exclude form progeny those with potentially conflicting combinations of mating type alleles, such as those simultaneously expressing A1 and A2 functions.

scholarly journals Occurrence and distribution of mating types A1 and A2 of Phytophthora infestans (Mont.) de Bary in the Czech Republic

2010 ◽  
Vol 42 (No. 2) ◽  
pp. 41-48 ◽  
Author(s):  
J. Mazáková ◽  
V. Táborský ◽  
M. Zouhar ◽  
P. Ryšánek ◽  
E. Hausvater ◽  
...  
Keyword(s):  
Czech Republic ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Mating Types ◽  
Pcr Markers ◽  
The Czech Republic ◽  
First Report

A total of 199 <i>Phytophthora infestans</i> isolates were obtained from leaves, tubers and fruits of infected crops of potato and tomato in different regions of the Czech Republic in 2003, 2004 and 2005. They were analysed for mating type using the conventional pairing assay and PCR markers; 107 isolates were of A1 and 92 of A2 mating type. No self-fertile isolate was found. Our study is the first report of the presence and distribution of the A2 mating type of <i>P. infestans</i> in the Czech Republic. The co-existence of the two mating types may enable the pathogen to reproduce sexually, thus enhancing the diversity of its population countrywide.

Sign in / Sign up

Export Citation Format

Share Document