scholarly journals Infection of Potatoes by Oospores of Phytophthora infestans in Soil

Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 876-876 ◽  
Author(s):  
A. Strömberg ◽  
L. Persson ◽  
M. Wikström
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Potato Crop ◽  
Selective Medium ◽  
Day Length ◽  
Talcum Powder ◽  
Soil P ◽  
Nodal Cuttings

Phytophthora infestans (Mont.) de Bary, causing late blight on potatoes and considered to be a typical airborne disease, was found to be infective also by oospores in the soil. P. infestans is heterothallic, and is known to reproduce asexually in Sweden since only one mating type, A1, was present until 1986. Since the 1970s, the other mating type, A2, of P. infestans has migrated to most parts of the world from its original location in central Mexico (2). When A1 and A2 meet, they may form oospores, which are thick-walled, resting structures, giving the pathogen a possibility to recombine as well as survive without its host, for instance in the soil. The soil stages of the pathogen are now therefore under intense investigation. Oospores of P. infestans were produced from two Scandinavian A1 and A2 isolates in Rye A broth mixed with talcum powder and dried for 7 weeks. The inoculum was mixed with sterile, standardized soil in concentrations of 10, 150, 250, and 400 oospores per ml of soil. Cv. Bintje plants cultivated in vitro from nodal cuttings on Murashige and Skoog medium were transplanted to the soil after rooting. Brown discolorations were obtained on the underground stems and tubers on potato plants grown in the two highest concentrations of oospores for 1 month at 15°C and 16-h day length. After 3 days of incubation on P. infestans-selective medium (3), sporangia covered the tissue from plants grown in 250 and 400 oospores per ml of soil and the pathogen was reisolated. This shows that germinating oospores of P. infestans can infect underground stems and tubers of potatoes in soil and further explains the early attack of late blight as observed in a potato crop in Sweden 1996 and 1997 (1). References: (1) B. Andersson et al. Potato Res. 41:305, 1998. (2) D. Andrivon. Phytopathology 85:1053, 1995. (3) G. W. Griffith et al. Mycologist 9:87, 1995.

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.

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 Respuesta de biosurfactantes producidos por Pseudomonas fluorescens para el control de la gota de la papa Phytophthora infestans (Mont) de Bary, bajo condiciones controlada.

2010 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Hugo F. Rivera ◽  
Erika P. Martínez ◽  
Jairo A. Osorio ◽  
Edgar Martínez
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Pseudomonas Fluorescens ◽  
Negative Impact ◽  
Potato Late Blight ◽  
Pathogen Resistance ◽  
Production Costs ◽  
In Vitro Assays

<p>Phytophthora infestans (Mont.) de Bary, agente causal de la gota de la papa, es considerado la principal limitante de la producción de este cultivo en Colombia. El control habitual del patógeno se realiza con fungicidas de tipo sistémico, que incrementan los costos de producción, pueden inducir la resistencia del patógeno y tiene un impacto negativo en el ambiente. Por tanto, se llevó a cabo este estudio con el propósito de buscar alternativas amigables con el ambiente, que hagan parte de un paquete tecnológico eficaz de control. Dos cepas nativas de Psedomonas fluorescens (039T y 021V), provenientes de cultivos de papa, fueron evaluadas contra P. infestans. Las suspensiones bacterianas y los biosurfactantes parcialmente purificados (BPP), producidos por éstas (obtenidos en medio mínimo de sales con querosén), fueron aplicados sobre foliolos desprendidos en ensayos in vitro y experimentos in vivo en plantas de papa, en condiciones controladas en casa de malla. Los resultados demostraron la capacidad que tienen los biosurfactantes y las suspensiones bacterianas para controlar al patógeno, ya que el BPP 039T logró reducir el nivel de severidad de la enfermedad en 79,9% in vitro y 38,5% in vivo, mientras que el BPP 021V redujo en 78,7% in vitro y 30,2% in vivo. Las suspensiones bacterianas redujeron el nivel de severidad en 72,4% (039T) y 66,1% (021V) en las evaluaciones in vitro y 35% en los experimentos in vivo. Los resultados de esta investigación muestran el potencial que tienen los biosurfactantes para el control de la gota en Colombia.</p><p> </p><p><strong>Evaluation of Biosurfactants Produced by Pseudomonas fluorescens for Potato Late Blight Control (Phytophthora infestans (Mont) de Bary) Under Controlled Conditions</strong></p><p>Phytophthora infestans (Mont.) de Bary, causal agent of potato late blight is considered the main limiting pathogen for the production of this crop in Colombia. The usual control of the disease has been performed with systemic fungicides which increase production costs, can induce pathogen resistance and have a negative impact on the environment. Therefore, this study was carried out in order to find effective and environmentally friendly control alternatives for potato late blight. Two Pseudomonas fluorescens native strains (039T and 021V) isolated from potato crops were evaluated against P. infestans. Bacterial suspensions (obtained from minimal salts medium added with kerosene) and partially purified biosurfactants (BPP) were applied on detached leaflets for in vitro assays and on potato plants in greenhouse, for in vivo assays and the measure of inhibitory effect of the disease was assessed. The results showed the ability of P. fluorescens biosurfactants and bacterial suspensions to control the pathogen. BPP 039T was able to reduce the level of severity disease by 79.9% in vitro and 38.5% in vivo, whereas BPP 021V decreased 78.7% in vitro and 30.2% in vivo. Bacterial suspensions reduced the severity level in 72.4% (039T) and 66.1% (021V) in vitro assessments and 35% in the in vivo experiment. These results show the potential of P. fluorescens biosurfactants to control the potato late blight in Colombia.</p>

scholarly journals Characterization of Phytophthora infestans in Wisconsin from 1993 to 1995

Plant Disease ◽  
1998 ◽  
Vol 82 (4) ◽  
pp. 434-436 ◽  
Author(s):  
K. D. Marshall-Farrar ◽  
M. McGrath ◽  
R. V. James ◽  
W. R. Stevenson
Keyword(s):  
Solanum Tuberosum ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Production Problem ◽  
Significant Production ◽  
Allozyme Genotype ◽  
Late Blight Of Potato

Late blight of potato (Solanum tuberosum), caused by Phytophthora infestans, recently reappeared in Wisconsin and was a significant production problem in 1994. P. infestans isolates collected in Wisconsin from 1993 to 1995 were characterized for the following traits: mating type, sensitivity to metalaxyl, and allozyme genotype for Glucose-6-phosphate isomerase (Gpi). Characterization of these isolates revealed that a new, more aggressive population (A2 mating type, metalaxyl resistant, and Gpi genotype 100/111/122) is displacing the old population (A1 mating type, metalaxyl sensitive, and Gpi genotype 86/100) in Wisconsin.

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 Mating type distribution of Phytophthora infestans (Mont.) de Bary in the Czech Republic in 2007 and 2008

2010 ◽  
Vol 46 (No. 3) ◽  
pp. 89-97 ◽  
Author(s):  
J. Mazáková ◽  
M. Zouhar ◽  
P. Ryšánek ◽  
V. Táborský ◽  
E. Hausvater ◽  
...  
Keyword(s):  
Czech Republic ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Caps Marker ◽  
The Czech Republic ◽  
Type Distribution ◽  
Pcr Assays

A total of 195 isolates of Phytophthora infestans were collected from late blight-diseased potatoes grown in several localities in the Czech Republic during the years 2007&ndash;2008. The isolates were analysed for mating type using the pairing test, CAPS marker assays and PCR assays. Of the 195 tested isolates, 28% were of the A1 mating type and 75% corresponded to the A2 mating type. Furthermore, oospores of P. infestans were microscopically detected in leaf samples from one locality.

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