Phytophthora erythroseptica

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Phytophthora erythroseptica
Germination of Phytophthora erythroseptica zoospores fmicb-10-00131-g002.jpg
Germination of Phytophthora erythroseptica zoospores
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Chromista
Phylum: Oomycota
Order: Peronosporales
Family: Peronosporaceae
Genus: Phytophthora
Species:
P. erythroseptica
Binomial name
Phytophthora erythroseptica
Pethybr., (1913)
Varieties

Phytophthora erythroseptica—also known as pink rot [1] along with several other species of Phytophthora —is a plant pathogen. It infects potatoes ( Solanum tuberosum ) causing their tubers to turn pink and damages leaves. It also infects tulips ( Tulipa ) damaging their leaves and shoots. [2]

Contents

Several species from the genus Phytophthora are believed to be involved in causing pink rot-like diseases. [3]

Disease cycle

Inoculation of potato tubers (cv. "Russet Norkotah") with Phytophthora erythroseptica zoospores. Either tuber slices (upper panels) or whole tubers (lower panels) of potato were inoculated with 5 zoospores suspended in 10 ml sterile distilled water (A1,A2), 5 zoospores suspended in 10 ml exudate derived from high-density zoospore suspension (1 x 104 spores/ml) (B1,B2), and 100 zoospores suspended in 10 ml sterile distilled water (C1,C2). Arrows indicate inoculation position. Inoculation of potato tubers (cv. "Russet Norkotah") with Phytophthora erythroseptica zoospores fmicb-10-00131-g003.jpg
Inoculation of potato tubers (cv. "Russet Norkotah") with Phytophthora erythroseptica zoospores. Either tuber slices (upper panels) or whole tubers (lower panels) of potato were inoculated with 5 zoospores suspended in 10 μl sterile distilled water (A1,A2), 5 zoospores suspended in 10 μl exudate derived from high-density zoospore suspension (1 × 104 spores/ml) (B1,B2), and 100 zoospores suspended in 10 μl sterile distilled water (C1,C2). Arrows indicate inoculation position.

As Phytophthora erythroseptica is an oomycete, its disease cycle follows that of similar Phytophthora species. [4] Oospores, sporangia, and zoospores can infect any part of the potato plant that is below ground. [5] Oospores serve as the primary form of inoculum, and can survive in the soil as long as seven years [6] Oospores produced in the field can overwinter and when thawed produce an oogonium and antheridium which will then lead to the production of sporangia, oospores, and zoospores. [7] This pathogen can be polycyclic, using sporangia as the secondary inoculum. Often this secondary inoculum infects tubers post harvest while in storage. [8] Zoospores are motile asexual spores that can move through soil water through the use of their flagella. These zoospores are also capable of encysting and infecting below ground plant tissue. [6]

Environmental conditions

Environmental factors play a critical role in the development and spread of P. erythroseptica on a field scale. This pathogen grows best in a warm and wet environment. It can infect a host without a wound, however the presence of a wound will increase infection greatly. A wound is needed for infection to occur when the tubers are in storage. [7] Very moist fields will have increased rates of infection as the amount of moisture makes it easy for the zoospores to move through the soil and infect tubers. Avoiding excessive late-season irrigation is imperative to minimize the risk for infection developing in the field. Avoiding excess free moisture is also important when storing potatoes after harvest. Soil moisture levels that are close to field capacity, whether the water comes from rainfall or irrigation, have been shown to increase the likelihood of soil-borne diseases. [9] This pathogen can also survive year to year as oospores in moist soil conditions, and also in volunteer potatoes or cull piles. Also, P. erythroseptica can germinate rapidly in warm soil conditions, thriving at temperatures around 77 °F (25 °C). [6]

Symptoms and host

P. erythroseptica is host specific, and typically only infects potatoes in moist soils. However, there are related pink rot species that infect raspberries, tomatoes, clover, and asparagus. [10] Symptoms of the disease in potatoes can be seen on the tubers, above ground vegetation, as well as the roots of the potatoes. Tuber symptoms are the most obvious to diagnose. Occasionally, a darkened color can be observed on the skin covering the infected portion of the tuber. When a suspected tuber is cut open, a dividing line can be seen between the healthy tuber tissue and the infected tissue. Infection spreads from the stolon end of tubers and usually leads to a rubbery or spongy consistency. Pink rot is not considered a slimy soft rot, since most of the tissue stays intact [6] The pinkish-salmon color of infected tubers can be seen once the phenolic compounds inside the tubers are exposed to oxygen for 15–30 minutes. After this time period the infected tissue turns to a brownish-blackish color [11] Aboveground symptoms can include chlorosis, stunting, and wilting of the plants. Roots and stolons can become blackened as well. The pink color is often used as the main symptom when making a firm diagnosis. The infected tubers often are watery and have a distinct smell. The potatoes plants themselves can sometimes be wilted however most symptoms are seen on the tuber. [12] The majority of diseased tubers get infected while in storage. The majority of symptoms are seen inside the tuber except for the rubbery appearance that the outside may have. There are often cases that show symptoms other than rotting, these are often due to a pathogen other than P. erythroseptica infecting the tuber along with pink rot.

Management

A multi-faceted approach is recommended to control pink rot. Sanitation of fields to reduce the amount of residues and volunteer potatoes is important to remove sources of inoculum or places the pathogen can overwinter. A crop rotation of 3–4 years is recommended to limit the amount of surviving spores in the soil, which is the main form of inoculum. Most cultivars of potatoes currently in production are susceptible to pink rot; however, some are more resistant than others. Varieties that are particularly susceptible are Dark Red Norland, Red LaSoda, Russet Norkotah, and Snowden. [13] [14] Some cultivars with better resistance are Atlantic, FL-1900, and Ranger Russet. In areas that Pink Rot is known to occur, it is best to avoid extremely susceptible cultivars. Additionally, planting only certified seed, avoiding recently problematic fields, and monitoring soil moistures and conditions, are all recommended practices when planting potatoes. It is not recommended to plant potatoes when fields are wet, or in low spots that can retain water for lengthy periods. Careful and thoughtful harvesting is important to minimize the risk of disease development. This includes allowing a good skin set before harvest, minimizing damage while harvesting, avoiding harvesting potatoes from wet areas that are more susceptible or likely to be diseased, and avoid harvesting in temperatures greater than 65 °F (18 °C). Curing potatoes in conditions of high humidity and cool temperatures to promote wound healing, and storing potatoes with adequate air movement and cool temperatures can also help prevent disease.

Chemical control can be difficult due to resistance development to some fungicides. Also there are few fungicidal modes of action that are effective. This includes the formerly successful metalaxyl, which is now widely ineffective due to resistance exhibited in the pathogen. Mefenoxam is another fungicide that pink rot pathogens have shown resistance against. However, research has shown that a combination of mefenoxam and oxathiapiprolin has demonstrated effectiveness on suppressing pink rot. [15] There have been studies done on phosphorous acid (Phostrol) as a systemic and contact fungicide against pink rot, but the exact mode of action has not yet been determined. Fluopicolide, part of the benzamide class of fungicides, has been shown to be effective at reducing pink rot on field scales. [16] There has not yet been cross-resistance between fluopicolide and mefenoxam, meaning these fungicides can be used rotationally to minimize the development of resistance.

Metalaxyl and similar chemicals disrupt RNA polymerase and prevent transcription. These chemicals are often used about a month before harvest. However, resistance to pink rot is being tested and encouraged in new cultivars of potatoes. [10]

Related Research Articles

Phytophthora sojae is an oomycete and a soil-borne plant pathogen that causes stem and root rot of soybean. This is a prevalent disease in most soybean growing regions, and a major cause of crop loss. In wet conditions the pathogen produces zoospores that move in water and are attracted to soybean roots. Zoospores can attach to roots, germinate, and infect the plant tissues. Diseased roots develop lesions that may spread up the stem and eventually kill the entire plant. Phytophthora sojae also produces oospores that can remain dormant in the soil over the winter, or longer, and germinate when conditions are favourable. Oospores may also be spread by animals or machinery.

<i>Phytophthora palmivora</i> Species of single-celled organism

Phytophthora palmivora is an oomycete that causes bud-rot of palms, fruit-rot or kole-roga of coconut and areca nut. These are among the most serious diseases caused by fungi and moulds in South India. It occurs almost every year in Malnad, Mysore, North & South Kanara, Malabar and other areas. Similar diseases of palms are also known to occur in Sri Lanka, Mauritius, and Sumatra. The causative organism was first identified as P. palmivora by Edwin John Butler in 1917.

<span class="mw-page-title-main">Powdery scab</span> Disease of potatoes

Powdery scab is a disease of potato tubers. It is caused by the cercozoan Spongospora subterranea f. sp. subterranea and is widespread in potato growing countries. Symptoms of powdery scab include small lesions in the early stages of the disease, progressing to raised pustules containing a powdery mass. These can eventually rupture within the tuber periderm. The powdery pustules contain resting spores that release anisokont zoospores to infect the root hairs of potatoes or tomatoes. Powdery scab is a cosmetic defect on tubers, which can result in the rejection of these potatoes. Potatoes which have been infected can be peeled to remove the infected skin and the remaining inside of the potato can be cooked and eaten.

Aphanomyces euteiches is a water mould, or oomycete, plant pathogen responsible for the disease Aphanomyces root rot. The species Aphanomyces euteiches can infect a variety of legumes. Symptoms of the disease can differ among hosts but generally include reduced root volume and function, leading to stunting and chlorotic foliage. Aphanomyces root rot is an important agricultural disease in the United States, Europe, Australia, New Zealand, and Japan. Management includes using resistant crop varieties and having good soil drainage, as well as testing soil for the pathogen to avoid infected fields.

<i>Phytophthora cactorum</i> Species of single-celled organism

Phytophthora cactorum is a fungal-like plant pathogen belonging to the Oomycota phylum. It is the causal agent of root rot on rhododendron and many other species, as well as leather rot of strawberries.

<i>Phytophthora medicaginis</i> Species of single-celled organism

Phytophthora medicaginis is an oomycete plant pathogen that causes root rot in alfalfa and chickpea. It is a major disease of these plants and is found wherever they are grown. P. medicaginis causes failure of stand establishment because of seedling death. Phytophthora medicaginis is part of a species complex with Phytophthora megasperma.

Phytophthora nicotianae or black shank is an oomycete belonging to the order Peronosporales and family Peronosporaceae.

Pythium irregulare is a soil borne oomycete plant pathogen. Oomycetes, also known as "water molds", are fungal-like protists. They are fungal-like because of their similar life cycles, but differ in that the resting stage is diploid, they have coenocytic hyphae, a larger genome, cellulose in their cell walls instead of chitin, and contain zoospores and oospores.

Pythium ultimum is a plant pathogen. It causes damping off and root rot diseases of hundreds of diverse plant hosts including corn, soybean, potato, wheat, fir, and many ornamental species. P. ultimum belongs to the peronosporalean lineage of oomycetes, along with other important plant pathogens such as Phytophthora spp. and many genera of downy mildews. P. ultimum is a frequent inhabitant of fields, freshwater ponds, and decomposing vegetation in most areas of the world. Contributing to the widespread distribution and persistence of P. ultimum is its ability to grow saprotrophically in soil and plant residue. This trait is also exhibited by most Pythium spp. but not by the related Phytophthora spp., which can only colonize living plant hosts.

Pythium aphanidermatum is a soil borne plant pathogen. Pythium is a genus in the class Oomycetes, which are also known as water molds. Oomycetes are not true fungi, as their cell walls are made of cellulose instead of chitin, they are diploid in their vegetative state, and they form coenocytic hyphae. Also, they reproduce asexually with motile biflagelette zoospores that require water to move towards and infect a host. Sexually, they reproduce with structures called antheridia, oogonia, and oospores.

Pythium graminicola is a plant pathogen infecting cereals.

Pythium volutum is a plant pathogen infecting wheat, barley, and turfgrass. It is known to be sensitive to some of the compounds typically present in selective media commonly used for isolating Pythium spp., so isolation may require alternative methods.

Sclerophthora macrospora is a protist plant pathogen of the class Oomycota. It causes downy mildew on a vast number of cereal crops including oats, rice, maize, and wheat as well as varieties of turf grass. The common names of the diseases associated with Sclerophthora macrospora include “crazy top disease” on maize and yellow tuft disease on turf grass. The disease is present all over the world, but it is especially persistent in Europe.

<i>Phytophthora capsici</i> Species of single-celled organism

Phytophthora capsici is an oomycete plant pathogen that causes blight and fruit rot of peppers and other important commercial crops. It was first described by L. Leonian at the New Mexico State University Agricultural Experiment Station in Las Cruces in 1922 on a crop of chili peppers. In 1967, a study by M. M. Satour and E. E. Butler found 45 species of cultivated plants and weeds susceptible to P. capsici In Greek, Phytophthora capsici means "plant destroyer of capsicums". P. capsici has a wide range of hosts including members of the families Solanaceae and Cucurbitaceae as well as Fabaceae.

Phytophthora fragariae is a fungus-like (oomycete) plant pathogen that causes red stele, otherwise known as Lanarkshire disease, in strawberries. Symptoms of red stele can include a red core in the roots, wilting of leaves, reduced flowering, stunting, and bitter fruit. The pathogen is spread via zoospores swimming through water present in the soil, released from sporangia.

Phytophthora megakarya is an oomycete plant pathogen that causes black pod disease in cocoa trees in west and central Africa. This pathogen can cause detrimental loss of yield in the economically important cocoa industry, worth approximately $70 billion annually. It can damage any part of the tree, causing total yield losses which can easily reach 20-25%. A mixture of chemical and cultural controls, as well as choosing resistant plant varieties, are often necessary to control this pathogen.

Buckeye rot of tomato is caused by three species of pathogens in the genus Phytophthora: P. nicotianae var. parasitica, P. capsici, and P. drechsleri. It is an oomycete that thrives in warm, wet conditions and lives in the soil. It is characterized by a bull’s eye pattern of dark brown rotting on the tomato fruit, and affects fruit that is close to, or lying on the soil. The easiest management is to keep the plant out of contact with the soil, although other chemical methods can be very effective. This disease commonly occurs in the southeast and south central areas of the United States. The disease has affected a large portion of crop yield in the United States as well as India. The relatively small genome size of Phytophthora parasitica compared to Phytophthora infestans gives researchers the unique ability to further examine its ability to cause disease.

Black rot on orchids is caused by Pythium and Phytophthora species. Black rot targets a variety of orchids but Cattleya orchids are especially susceptible. Pythium ultimum and Phytophthora cactorum are known to cause black rot in orchids.

Cranberry Root Rot (CRR) is a disease in cranberries that can cause a decline in yield.

References

  1. ↑ Wharton, Phillip; Kirk, William. "Pink Rot". Michigan Potato Diseases. Michigan State University. Retrieved 22 July 2014.
  2. ↑ "Phytophthora erythroseptica Pethybr., 1913 (a blight fungus)". www.bioimages.org.uk. Archived from the original on 30 June 2007.
  3. ↑ Mostowfizadeh-Ghalamfarsa, R; Panabieres, F; Banihashemi, Z; Cooke, DE (April 2010). "Phylogenetic relationship of Phytophthora cryptogea Pethybr. & Laff and P. drechsleri Tucker". Fungal Biology. 114 (4): 325–39. doi:10.1016/j.funbio.2010.02.001. PMID   20943142.
  4. ↑ "Phytophthora Database". www.phytophthoradb.org. Retrieved 1 December 2016.
  5. ↑ Griffiths, Helen. "Pink Rot of Potato Caused by Phytophthora Erythroseptica in Pennsylvania" (PDF).
  6. 1 2 3 4 Warton, Phillip., Kirk, William. Potato Diseases: Pink Rot (E2993). 31 January 2017. Michigan State University Extension http://msue.anr.msu.edu/resources/potato_diseases_pink_rot_e2993
  7. 1 2 "Michigan Potato Diseases – Pink Rot". www.potatodiseases.org. Retrieved 1 December 2016.
  8. ↑ Vargas, Luis A.; Nielsen, L. W. (1972). "Phytophthora erythroseptica in Peru: Its identification and pathogenesis". American Potato Journal. 49 (8): 309–320. doi:10.1007/BF02861669. ISSN   0003-0589. S2CID   8563800.
  9. ↑ Isaacs, Julienne. Cultural Practices Important for Managing Pink Rot and Leak. Manitoba Co-Operator. 7 May 2015. https://www.manitobacooperator.ca/crops/cultural-practices-important-for-managing-pink-rot-and-leak/
  10. 1 2 Parry, David W. (1990). Plant Pathology in Agriculture. Cambridge: Cambridge UP. p. 291.
  11. ↑ "UC IPM: UC Management Guidelines for Pink Rot on Potato". ipm.ucanr.edu. Retrieved 1 December 2016.
  12. ↑ "Pink rot | AHDB Potatoes". potatoes.ahdb.org.uk. Retrieved 1 December 2016.
  13. ↑ Salas, Bacilio., Sector, Gary A., Taylor, R.J., Gudmestad, Neil C.. Assessment of Resistance of Tubers of Potato Cultivars to Phytopthora erythroseptica and Pythium ultimum. January 2003. North Dakota State University, Fargo. Department of Plant Pathology. https://www.ndsu.edu/fileadmin/potatopathology/potato_trials/Assessment_of_Resistance_of_Tubers_of_Potato_Cultivars_to_Phytophthora_erythroseptica_and_Pythium_ultimum.pdf
  14. ↑ Zitter, Thomas A. Update on Pink Rot and Pythium Leak Control for Potatoes. 2002. Vegetable MD Online. Cornell University, Department of Plant Pathology. http://vegetablemdonline.ppath.cornell.edu/NewsArticles/Potoato_Pink_Leak.htm
  15. ↑ Orondis RidomilGoldSL Syngenta. A Gold Standard for Management of Pink Rot on Potatoes. 2017. http://www.syngenta-us.com/prodrender/imagehandler.ashx?ImID=36049054-60db-42da-a22c-efad05f978a8&fTy=0&et=8
  16. ↑ Zhang, Xuemei (Missi). Chemical and Non-Chemical Control of Potato Pink Rot. 15 December 2016. The University of Maine Digital Commons. http://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=3651&context=etd
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