Plum pox
Encyclopedia
Plum pox, also known as sharka, is the most devastating viral disease of stone fruit from the genus Prunus
. The disease is caused by the plum pox virus
(PPV), and the different strains may infect a variety of stone fruit species including peach
es, apricot
s, plum
s, nectarine, almond
s, and sweet and tart cherries
. Wild and ornamental species of Prunus may also become infected by some strains of the virus.
The virus is transmitted by aphid
s and by the transfer of infected plant material to new locations. Plum pox poses no danger to consumers. But it can ruin the marketability of stone fruit by causing acidity and deformities. The only way to manage the disease is to destroy all infected trees, which can cause significant economic losses. A genetically modified plum resistant to plum pox virus, named "HoneySweet", has been developed but is not commercially available.
virus. There are six strains of plum pox virus: PPV-D, PPV-M, PPV-EA, PPV-C, PPV-Rec (Recombinant), and PPV-W. PPV-M isolates are more aggressive in peach, are aphid
vectored more efficiently, and spread more rapidly in an orchard. PPV-M has been reported to be seed
transmitted, the other PPV strains are known not be transmitted through seeds. Both PPV strains M and D infest peach, plum, and apricot. PPV-C infects sweet and tart cherry naturally and is the only strain known to do so, it has infected other Prunus hosts experimentally.
Several aphid species can transmit plum pox within an orchard and over short distances (200-300 meters) to trees in nearby orchard
s. Unlike some other viruses, like barley yellow dwarf virus, PPV is not persistent in the aphid and is transferred from the mouthparts of the aphid between plants. Long distance spread usually occurs as a result of the movement of infected nursery stock or propagative materials. Once a plant is infected the virus is systemic and occurs in the cytoplasm
of cell
s from all parts of the plant.
When a host tree is infected by plum pox, the infection eventually results in severely reduced fruit production, and the fruit that is produced is often misshapen and blemished. The presence of plum pox can also enhance the effects of other endemic viruses infecting various species of the genus Prunus, such as prune dwarf virus, Prunus necrotic (browning) ringspot virus, and apple chlorotic (yellowing) leaf spot virus, resulting in still greater economic losses.
In peach
, infected trees may exhibit color-breaking symptoms in the blossom
s. This appears as darker pink stripes on the flower petal
s and can be useful for early season surveys. Symptoms can be present in young leaves in the spring and /or on developing fruit
. Some trees show no symptoms on leaves or fruit.
Not all infection in Prunus are characterized by a ring symptom on leaves. Several cultivars show yellowing line patterns and blotches, or necrotic ring symptoms on expanded leaves. Leaf distortion has also been observed. Infected fruit can develop yellow rings or blotches, or brown rings, and some plum
and apricot
fruit can be severely deformed and bumpy. The seed of many infected apricots and some plums show rings.
Many non-Prunus species, in at least nine plant families, have been infected artificially with one or more strains of the plum pox virus, and in some cases found naturally infected in the field. The manintance of the virus in non-Prunus species complicates disease management.
There is no cure or treatment for the disease once a tree becomes infected. Infected trees must be destroyed. Once the disease becomes established, control and prevention measures for plum pox include field surveys, use of certified nursery materials, control of aphids, and elimination of infected trees in nurseries and orchards.
Sources of resistance exist in Prunus, but are not common. A team of scientists from the United States
and France
has genetically engineered a plum pox-resistant plum called C5, and the resistance can be transferred through hybridization to other plum trees. The transgenic plum expresses a plum pox virus coat protein, the plant produces the coat protein mRNA and it is processed by a system called post transcriptional gene silencing (PTGS), which functions like the plants immune system and is mechanistically similar to RNAi
. C5 provides a unique source of germplasm
for future breeding programs worldwide. Similar success has not yet occurred in attempt to genetically modify other Prunus species, although these efforts are ongoing.
In the fall of 1999, plum pox strain PPV-D was detected in an Adams County
, Pennsylvania
orchard. This was the first time that plum pox had been found in North America
. The infected areas in Pennsylvania have been quarantined to prevent the spread of the disease, and infected trees have been destroyed.
Since this time, as a result of random surveying done in 2000, detection has also occurred in Nova Scotia
and in Southern Ontario, particularly in the Niagara Region. Like the United States infection, the Canadian Food Inspection Agency
has put into effect quarantine zones throughout Southern Ontario in a bid to prevent the spread of PPV. The virus has yet to be found in other areas of Canada which contain susceptible trees despite intense surveying. The Canadian plum pox eradication initiative has involved large numbers of samples tested for the plum pox virus. Samples are tested through a technology known as enzyme linked immunosorbent assay (ELISA
). The University of Guelph - Laboratory Services Division has performed over 4,000,000 tests in the past 7 years in support of this initiative.
Prunus
Prunus is a genus of trees and shrubs, which includes the plums, cherries, peaches, apricots and almonds. There are around 430 species spread throughout the northern temperate regions of the globe. Many members of the genus are widely cultivated for fruit and ornament.-Botany:Members of the genus...
. The disease is caused by the plum pox virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
(PPV), and the different strains may infect a variety of stone fruit species including peach
Peach
The peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...
es, apricot
Apricot
The apricot, Prunus armeniaca, is a species of Prunus, classified with the plum in the subgenus Prunus. The native range is somewhat uncertain due to its extensive prehistoric cultivation.- Description :...
s, plum
Plum
A plum or gage is a stone fruit tree in the genus Prunus, subgenus Prunus. The subgenus is distinguished from other subgenera in the shoots having a terminal bud and solitary side buds , the flowers in groups of one to five together on short stems, and the fruit having a groove running down one...
s, nectarine, almond
Almond
The almond , is a species of tree native to the Middle East and South Asia. Almond is also the name of the edible and widely cultivated seed of this tree...
s, and sweet and tart cherries
Cherry
The cherry is the fruit of many plants of the genus Prunus, and is a fleshy stone fruit. The cherry fruits of commerce are usually obtained from a limited number of species, including especially cultivars of the wild cherry, Prunus avium....
. Wild and ornamental species of Prunus may also become infected by some strains of the virus.
The virus is transmitted by aphid
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...
s and by the transfer of infected plant material to new locations. Plum pox poses no danger to consumers. But it can ruin the marketability of stone fruit by causing acidity and deformities. The only way to manage the disease is to destroy all infected trees, which can cause significant economic losses. A genetically modified plum resistant to plum pox virus, named "HoneySweet", has been developed but is not commercially available.
Biology
The plum pox virus is a linear single stranded RNARNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
virus. There are six strains of plum pox virus: PPV-D, PPV-M, PPV-EA, PPV-C, PPV-Rec (Recombinant), and PPV-W. PPV-M isolates are more aggressive in peach, are aphid
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...
vectored more efficiently, and spread more rapidly in an orchard. PPV-M has been reported to be seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
transmitted, the other PPV strains are known not be transmitted through seeds. Both PPV strains M and D infest peach, plum, and apricot. PPV-C infects sweet and tart cherry naturally and is the only strain known to do so, it has infected other Prunus hosts experimentally.
Pathology
Orchard
An orchard is an intentional planting of trees or shrubs that is maintained for food production. Orchards comprise fruit or nut-producing trees which are grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive...
s. Unlike some other viruses, like barley yellow dwarf virus, PPV is not persistent in the aphid and is transferred from the mouthparts of the aphid between plants. Long distance spread usually occurs as a result of the movement of infected nursery stock or propagative materials. Once a plant is infected the virus is systemic and occurs in the cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
of cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
s from all parts of the plant.
When a host tree is infected by plum pox, the infection eventually results in severely reduced fruit production, and the fruit that is produced is often misshapen and blemished. The presence of plum pox can also enhance the effects of other endemic viruses infecting various species of the genus Prunus, such as prune dwarf virus, Prunus necrotic (browning) ringspot virus, and apple chlorotic (yellowing) leaf spot virus, resulting in still greater economic losses.
Peach
The peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...
, infected trees may exhibit color-breaking symptoms in the blossom
Blossom
In botany, blossom is a term given to the flowers of stone fruit trees and of some other plants with a similar appearance that flower profusely for a period of time in spring...
s. This appears as darker pink stripes on the flower petal
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
s and can be useful for early season surveys. Symptoms can be present in young leaves in the spring and /or on developing fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
. Some trees show no symptoms on leaves or fruit.
Not all infection in Prunus are characterized by a ring symptom on leaves. Several cultivars show yellowing line patterns and blotches, or necrotic ring symptoms on expanded leaves. Leaf distortion has also been observed. Infected fruit can develop yellow rings or blotches, or brown rings, and some plum
Plum
A plum or gage is a stone fruit tree in the genus Prunus, subgenus Prunus. The subgenus is distinguished from other subgenera in the shoots having a terminal bud and solitary side buds , the flowers in groups of one to five together on short stems, and the fruit having a groove running down one...
and apricot
Apricot
The apricot, Prunus armeniaca, is a species of Prunus, classified with the plum in the subgenus Prunus. The native range is somewhat uncertain due to its extensive prehistoric cultivation.- Description :...
fruit can be severely deformed and bumpy. The seed of many infected apricots and some plums show rings.
Many non-Prunus species, in at least nine plant families, have been infected artificially with one or more strains of the plum pox virus, and in some cases found naturally infected in the field. The manintance of the virus in non-Prunus species complicates disease management.
Management
Sources of resistance exist in Prunus, but are not common. A team of scientists from the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
has genetically engineered a plum pox-resistant plum called C5, and the resistance can be transferred through hybridization to other plum trees. The transgenic plum expresses a plum pox virus coat protein, the plant produces the coat protein mRNA and it is processed by a system called post transcriptional gene silencing (PTGS), which functions like the plants immune system and is mechanistically similar to RNAi
RNAI
RNAI is a non-coding RNA that is an antisense repressor of the replication of some E. coli plasmids, including ColE1. Plasmid replication is usually initiated by RNAII, which acts as a primer by binding to its template DNA. The complementary RNAI binds RNAII prohibiting it from its initiation role...
. C5 provides a unique source of germplasm
Germplasm
A germplasm is a collection of genetic resources for an organism. For plants, the germplasm may be stored as a seed collection or, for trees, in a nursery.-See also:*Germ plasm, the germ cell determining zone...
for future breeding programs worldwide. Similar success has not yet occurred in attempt to genetically modify other Prunus species, although these efforts are ongoing.
Distribution
| Disease Status | Country |
|---|---|
| Restricted Distribution | Albania Albania Albania , officially known as the Republic of Albania , is a country in Southeastern Europe, in the Balkans region. It is bordered by Montenegro to the northwest, Kosovo to the northeast, the Republic of Macedonia to the east and Greece to the south and southeast. It has a coast on the Adriatic Sea... , Austria Austria Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the... , Canada Canada Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean... , Cyprus Cyprus Cyprus , officially the Republic of Cyprus , is a Eurasian island country, member of the European Union, in the Eastern Mediterranean, east of Greece, south of Turkey, west of Syria and north of Egypt. It is the third largest island in the Mediterranean Sea.The earliest known human activity on the... , Czech Republic Czech Republic The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest.... , France France The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France... , Italy Italy Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and... , Luxembourg Luxembourg Luxembourg , officially the Grand Duchy of Luxembourg , is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the North as part of the Ardennes massif, and the Gutland in the south... , Moldova Moldova Moldova , officially the Republic of Moldova is a landlocked state in Eastern Europe, located between Romania to the West and Ukraine to the North, East and South. It declared itself an independent state with the same boundaries as the preceding Moldavian Soviet Socialist Republic in 1991, as part... , Norway Norway Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million... , Portugal Portugal Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the... , Southern Russia Russia Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects... , Slovenia Slovenia Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of... , Spain Spain Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula... , Syria Syria Syria , officially the Syrian Arab Republic , is a country in Western Asia, bordering Lebanon and the Mediterranean Sea to the West, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest.... , Turkey Turkey Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe... , Ukraine Ukraine Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia... , United Kingdom United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... , United States United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... |
| Widespread | Bulgaria Bulgaria Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east... , Croatia Croatia Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ... , Germany Germany Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate... , Greece Greece Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe.... , Hungary Hungary Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The... , Poland Poland Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north... , Romania Romania Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea... , Slovakia Slovakia The Slovak Republic is a landlocked state in Central Europe. It has a population of over five million and an area of about . Slovakia is bordered by the Czech Republic and Austria to the west, Poland to the north, Ukraine to the east and Hungary to the south... |
| Introduced, Established | Azores Azores The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the... , Bosnia-Herzegovina, Egypt Egypt Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world... , Former USSR including Central Asia Central Asia Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north... , India India India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world... , Lithuania Lithuania Lithuania , officially the Republic of Lithuania is a country in Northern Europe, the biggest of the three Baltic states. It is situated along the southeastern shore of the Baltic Sea, whereby to the west lie Sweden and Denmark... |
| Introduced, Presumably Eradicated | Belgium Belgium Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many... , Netherlands Netherlands The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders... , Switzerland Switzerland Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition.... |
| Present Status Unknown | Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far... , Denmark Denmark Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark... |
| Modified from: Levy et al. 2000. Plum Pox Potyvirus Disease of Stone Fruits. American Phytopathological Society | |
In the fall of 1999, plum pox strain PPV-D was detected in an Adams County
Adams County, Pennsylvania
Adams County is a county in the U.S. state of Pennsylvania. As of the 2010 census, the population was 101,407. It was created on January 22, 1800, from part of York County and named in honor of the second President of the United States, John Adams...
, Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
orchard. This was the first time that plum pox had been found in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. The infected areas in Pennsylvania have been quarantined to prevent the spread of the disease, and infected trees have been destroyed.
Since this time, as a result of random surveying done in 2000, detection has also occurred in Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
and in Southern Ontario, particularly in the Niagara Region. Like the United States infection, the Canadian Food Inspection Agency
Canadian Food Inspection Agency
The Canadian Food Inspection Agency is a science based regulatory agency that is dedicated to the safeguarding of food, animals, and plants, which enhance the health and well-being of Canada's people, environment and economy...
has put into effect quarantine zones throughout Southern Ontario in a bid to prevent the spread of PPV. The virus has yet to be found in other areas of Canada which contain susceptible trees despite intense surveying. The Canadian plum pox eradication initiative has involved large numbers of samples tested for the plum pox virus. Samples are tested through a technology known as enzyme linked immunosorbent assay (ELISA
ELISA
Enzyme-linked immunosorbent assay , is a popular format of a "wet-lab" type analytic biochemistry assay that uses one sub-type of heterogeneous, solid-phase enzyme immunoassay to detect the presence of a substance in a liquid sample."Wet lab" analytic biochemistry assays involves detection of an...
). The University of Guelph - Laboratory Services Division has performed over 4,000,000 tests in the past 7 years in support of this initiative.
External links
- Contamination by the SHARKA virus in France: a synthesis
- West Virginia Department of Agriculture Plum Pox Virus Information
- Species Profile- Plum Pox (Potyviruses), National Invasive Species Information Center, United States National Agricultural LibraryUnited States National Agricultural LibraryThe United States National Agricultural Library is one of the world's largest agricultural research libraries, and serves as a National Library of the United States and as the library of the United States Department of Agriculture...
. Lists general information and resources for Plum Pox.