Melon necrotic spot virus

Last updated
Melon necrotic spot virus
Melon Necrotic Spot Virus on Older Leaves.png
Melon necrotic spot on older leaf
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Kitrinoviricota
Class: Tolucaviricetes
Order: Tolivirales
Family: Tombusviridae
Genus: Gammacarmovirus
Species:
Melon necrotic spot virus

Melon necrotic spot virus (MNSV) is a virus that belongs to the genus Gammacarmovirus (splitted from formerly Carmovirus) of the family Tombusviridae. It has been observed in several countries in the Americas, Africa, Asia, and Europe. It is considered to be an endemic virus in greenhouses and field productions of Cucurbitaceae crops, including melon ( Cucumis melo ), cucumber ( Cucumbis sativus ), and watermelon ( Citrullus lanatus ). MNSV is mainly spread through infected soil, seedlings, insects, and by the root-inhabiting fungus vector Olpidium bornovanus Symptoms vary between Curbitaceae crops, but generally consist of chlorosis, brown necrotic lesions, leaf wilt, fruit decay, and plant death. Management of the disease consists of preventing infection by rotating fields and crops, steam sterilization, and disposal of infected plants. Also, treated seeds with heat or chemicals are efficient in preventing infection. MNSV is important in melon plants as it causes vast economical damage worldwide reducing significant yields.

Contents

Hosts and symptoms

Discoloration in the rind of a seedless watermelon caused by MNSV MNSV Discoloration of Rind.png
Discoloration in the rind of a seedless watermelon caused by MNSV

Melons are one of the most important crops in the tropical and temperate areas of the world. MNSV has been found to have a very narrow host range, restricted to members of the family Cucurbitaceae. In particular, the hosts include watermelons (Citrullus lanatus), cucumbers (Cucumis sativus), and melons (Cucumis melo).[ citation needed ]

On watermelon, MNSV produces chlorotic lesions on leaves, stems, and/or cotyledons, which turn into dark brown local lesions. [1] These brown local lesions indicate necrosis occurring on the specific plant parts. Also, the fruit itself may become infected. The fruit may become misshaped with the melon flesh becoming discolored and brown ring rot becoming evident. The fruit can decay while on the plant in severe cases. [2]

In cucumbers, MNSV produces chlorotic lesions on leaves and cotyledons. In the chlorotic lesions, necrotic brown pinpoint lesions enlarge throughout the lesions, causing the leaf and/or cotyledons to wilt and die. Stem necrosis is generally absent. The cucumber fruit itself will not display lesions. [1]

In melons, such as rockmelon, muskmelon, and cantaloupe, MNSV produces necrotic lesions on the leaves and/or cotyledons. The roots will also exhibit necrotic lesions. The melon fruit decreases in size and displays necrotic spots on the rind as well.[ citation needed ]

Overall, infection of the crop will produce small chlorotic spots on the leaves, stems, and/or cotyledons, which turn brown while enlarging in size. The necrotic lesions can cause death to the plant structure and plant as a whole. MNSV symptoms tend to be more severe at lower temperatures. Once a plant is infected with MNSV the infection persists until plant death. [3] If no infection occurs, MNSV can survive in soil for several years. [4]

Disease cycle

MNSV is seed-borne, soil-borne, and vector-borne. It spreads via two means: the soil fungus Olpidium bornovanus, which is soil-borne and moisture dependent, and the cucumber beetles: western spotted cucumber beetle ( Diabrotica undecimpunctata undecimpunctata) and banded cucumber beetle (D. balteata). [5] Since it is a virus, it is transmitted through vectors. [4] Vectors are orgasms with which any pathogens are transmitted.

Through seed, infection occurs when the seeds are scattered in soil containing the virus-free fungus. This is known as “vector-mediated seed transmission”. MNSV which is carried on the seed is released into the soil. [4]

The virus attaches to the external surface of the zoospores of Olipidium bornovanus using the MNSV coat protein for attachment. The fungus itself is observed in only the root tissue of the virus-infected plants. Once the fungus invades the plant roots it transmits the virus to the host plants. [6] The processes is then repeated once seeds are created.

Lastly, cucumber beetles act as insect vectors for MNSV. They feed on flowers of the plants, if these are available, rather than feeding on leaves. This causes reductions in fruit yield. If flowers are not available, adult beetles prefer the foliage of the cucurbit crops. [7] This is the method by which the beetles spread the virus in a persistent manner.

Environment

MNSV can be found in tropical and temperate areas in the world where its host crops thrive. The first symptoms sighting of MNSV was seen in Japan. [8] The virus has since been reported to be infecting melons in Western Europe, Eastern Europe, the Americas, Asia, and lastly, Australia. In the United States, MNSV can be mainly found in the southern states where climates are favorable. Symptoms are visible during the spring and autumn seasons due to MNSV requiring higher humidity with specific temperature ranges. The virus begins to inoculate plants with symptoms beginning to show when temperatures are under 25°C, with the most severe temperature showing when temperatures drop slightly below 20°C. [9]

Management

Management of MNSV can be achieved through multiple methods of control. Targeting Olipidium bornovanus is effective in stopping the vector from spreading the disease. Control of the Olipidium vector can be obtained via soil sterilization with steam or methyl bromide. Controlling pest insects is also effective. The active ingredient(s) in insecticides kill the beetles, reducing the spread of the virus.

Since MNSV is soil-borne, soil disinfection and prevention of mechanical transmission is important. Removing and disposing infected plants from the soil can help disinfect soil from the virus. Also, cleaning machinery between fields is essential to limit the spread of the virus. If infected soil remains on machinery and equipment, it will spread to other fields. In cases of infection rates being too high in the particular field, crop rotation is necessary.

The virus is also seed-borne. Ensuring clean seed when planting is crucial. In order to eradicate MNSV in melon seeds without hindering germination, heat treatment of 144 hours at 70°C is necessary. [10] Also, Trisodium phosphate is an effective chemical that can be used against seeds infected with MNSV. [11]

Lastly, breeding for resistance is the most effective method of control against MNSV. Two cultivars in melon that exhibit resistance are “Gulfstream” and the Korean accession PI 161375. Both exhibit a single recessive gene, nsv, which is reported to control the only resistance found to MNSV in melon. [12]

Importance

Although MNSV is not well known, it has produced major outbreaks leading back to the first studies of the virus in 1966 in Japan. Kishi first discovered MNSV on Cucumis melo in a greenhouse setting in that year. For the next two decades, there were minor studies in greenhouse and field studies in California and the Netherlands on the transmission of MNSV. In 1982, nurserymen at Brough, Humberside first discovered the disease on their cucumber plants. In May 1983, some plants showed chlorosis and occasional necrotic spots on leaves. By August of that year, nearly 50% of the 120,000 plants in the greenhouse were severely infected and over 60% had MNSV by October. Fortunately the fruits of these plants did not display any symptoms although there was definite reduction in crop yield. [13]

More recently researchers have discovered a non-systemic strain of MNSV on cucurbitaceous plants in a 2008 study. This strain was isolated from a watermelon plant and showed similar characteristics to the former MNSV pathogen except for the fact that it wasn't serologically the same and did not show symptoms on six MNSV susceptible plants. [14] For over four decades, this pathogen has proven to be important due to the agricultural community’s lack of knowledge on MNSV as well its ability to wipe out over 60% of the crop yield as discovered during the Humberside incident.

Related Research Articles

<i>Passiflora edulis</i> Species of flowering plant in the passion flower family

Passiflora edulis, commonly known as passion fruit, is a vine species of passion flower native to the region of southern Brazil through Paraguay to northern Argentina. It is cultivated commercially in tropical and subtropical areas for its sweet, seedy fruit.

<span class="mw-page-title-main">Fusarium wilt</span> Fungal plant disease

Fusarium wilt is a common vascular wilt fungal disease, exhibiting symptoms similar to Verticillium wilt. This disease has been investigated extensively since the early years of this century. The pathogen that causes Fusarium wilt is Fusarium oxysporum. The species is further divided into formae speciales based on host plant.

Bacterial fruit blotch (BFB) affects cucurbit plants around the world and can be a serious threat to farmers because it spreads through contaminated seed. BFB is the result of an infection by Gram-negative Acidovorax citrulli bacteria, which has only been recently studied in detail. Members of A. citrulli are Gram-negative rod shaped bacteria with the dimensions 0.5× 1.7 μm. They move via polar flagella. No known reliable sources of BFB resistance exist today, so seed hygiene and thorough testing of breeding facilities are the best way to control spreading. No known control methods, however, are extremely reliable for reducing BFB infection.

<span class="mw-page-title-main">Leaf spot</span> Damaged areas of leaves

A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions often have a centre of necrosis. Symptoms can overlap across causal agents, however differing signs and symptoms of certain pathogens can lead to the diagnosis of the type of leaf spot disease. Prolonged wet and humid conditions promote leaf spot disease and most pathogens are spread by wind, splashing rain or irrigation that carry the disease to other leaves.

Pyrenophora teres is a necrotrophic fungal pathogen of some plant species, the most significant of which are economically important agricultural crops such as barley. Toxins include aspergillomarasmine A and related compounds.

<i>Ascochyta</i> Genus of fungi

Ascochyta is a genus of ascomycete fungi, containing several species that are pathogenic to plants, particularly cereal crops. The taxonomy of this genus is still incomplete. The genus was first described in 1830 by Marie-Anne Libert, who regarded the spores as minute asci and the cell contents as spherical spores. Numerous revisions to the members of the genus and its description were made for the next several years. Species that are plant pathogenic on cereals include, A. hordei, A. graminea, A. sorghi, A. tritici. Symptoms are usually elliptical spots that are initially chlorotic and later become a necrotic brown. Management includes fungicide applications and sanitation of diseased plant tissue debris.

Alternaria dauci is a plant pathogen. The English name of the disease it incites is "carrot leaf blight".

<i>Didymella bryoniae</i> Species of fungus

Didymella bryoniae, syn. Mycosphaerella melonis, is an ascomycete fungal plant pathogen that causes gummy stem blight on the family Cucurbitaceae, which includes cantaloupe, cucumber, muskmelon and watermelon plants. The anamorph/asexual stage for this fungus is called Phoma cucurbitacearum. When this pathogen infects the fruit of cucurbits it is called black rot.

<i>Cucumber mosaic virus</i> Species of virus

Cucumber mosaic virus (CMV) is a plant pathogenic virus in the family Bromoviridae. This virus has a worldwide distribution and a very wide host range, having the reputation of the widest host range of any known plant virus. It can be transmitted from plant to plant both mechanically by sap and by aphids in a stylet-borne fashion. It can also be transmitted in seeds and by the parasitic weeds, Cuscuta sp. (dodder).

<i>Prunus necrotic ringspot virus</i> Species of virus

Prunus necrotic ringspot virus (PNRSV) is a plant pathogenic virus causing ring spot diseases affecting species of the genus Prunus, as well as other species such as rose and hops. PNRSV is found worldwide due to easy transmission through plant propagation methods and infected seed. The virus is in the family Bromoviridae and genus Ilarvirus. Synonyms of PNRSV include European plum line pattern virus, hop B virus, hop C virus, plum line pattern virus, sour cherry necrotic ringspot virus, and peach ringspot virus.

Tobacco necrosis virus A (TNV) is a plant pathogenic virus of the family Tombusviridae.

<i>Tobacco ringspot virus</i> Species of virus

Tobacco ringspot virus (TRSV) is a plant pathogenic virus in the plant virus family Secoviridae. It is the type species of the genus Nepovirus. Nepoviruses are transmitted between plants by nematodes, thrips, mites, grasshoppers, and flea beetles. TRSV is also easily transmitted by sap inoculation and transmission in seeds has been reported. In recent cases it has also been shown to appear in bees, but no transmission to plants from bees has been noted.

<i>Orthotospovirus</i> Genus of viruses

Orthotospovirus is a genus of negative-strand RNA viruses, in the family Tospoviridae of the order Bunyavirales, which infects plants. Tospoviruses take their name from the species Tomato spotted wilt orthotospovirus (TSWV) which was discovered in Australia in 1919. TSWV remained the only known member of the family until the early 1990s when genetic characterisation of plant viruses became more common. There are now at least twenty species in the genus with more being discovered on a regular basis. Member viruses infect over eight hundred plant species from 82 different families.

Black rot, caused by the bacterium Xanthomonas campestris pv. campestris (Xcc), is considered the most important and most destructive disease of crucifers, infecting all cultivated varieties of brassicas worldwide. This disease was first described by botanist and entomologist Harrison Garman in Lexington, Kentucky, US in 1889. Since then, it has been found in nearly every country in which vegetable brassicas are commercially cultivated.

<i>Watermelon mosaic virus</i> Species of virus

Watermelon mosaic virus (WMV) also known as Marrow mosaic virus, Melon mosaic virus, and until recently Watermelon mosaic virus type 2 (WMV-2), is a plant pathogenic virus that causes viral infection in many different plants. The virus itself is referred to as Watermelon Mosaic Virus II or WMV-2 and is an isolate of the U.S. WMV-2 is a ssRNA positive strand virus that is part of the Potyviridae or Potyvirus clade. Like all RNA viruses, it contains a protein capsid which protects the inner viral RNA. First described on squash in Florida, WMV arose from a unique recombination of genetic material contributed by Soybean mosaic virus (SMV) and Bean common mosaic virus (BCMV) along with Peanut Stripe virus (PSV).

<i>Diabrotica balteata</i> Species of beetle

Diabrotica balteata is a species of cucumber beetle in the family Chrysomelidae known commonly as the banded cucumber beetle. It occurs in the Americas, where its distribution extends from the United States to Colombia and Venezuela in South America. It is also present in Cuba. It is a pest of a variety of agricultural crops.

Gummy stem blight is a cucurbit-rot disease caused by the fungal plant pathogen Didymella bryoniae. Gummy stem blight can affect a host at any stage of growth in its development and affects all parts of the host including leaves, stems and fruits. Symptoms generally consist of circular dark tan lesions that blight the leaf, water soaked leaves, stem cankers, and gummy brown ooze that exudes from cankers, giving it the name gummy stem blight. Gummy stem blight reduces yields of edible cucurbits by devastating the vines and leaves and rotting the fruits. There are various methods to control gummy stem blight, including use of treated seed, crop rotation, using preventative fungicides, eradication of diseased material, and deep plowing previous debris.

Cocoa necrosis virus (CoNV) is a plant pathogenic virus of the genus nepovirus that infects Theobroma cacao en natura causing cacao necrosis disease. CoNV is considered synonymous with Strain S of cacao swollen shoot virus. Unlike Cacao swollen shoot virus, it is not transmitted by mealybugs nor vectored by aphids, beetles, or leafhoppers that also commonly infest cacao. It is serologically, distantly related to Tomato black ring virus and very distantly related to Grapevine chrome mosaic virus.

<span class="mw-page-title-main">Alternaria leaf spot</span> Fungal plant disease

Alternaria leaf spot or Alternaria leaf blight are a group of fungal diseases in plants, that have a variety of hosts. The diseases infects common garden plants, such as cabbage, and are caused by several closely related species of fungi. Some of these fungal species target specific plants, while others have been known to target plant families. One commercially relevant plant genus that can be affected by Alternaria Leaf Spot is Brassica, as the cosmetic issues caused by symptomatic lesions can lead to rejection of crops by distributors and buyers. When certain crops such as cauliflower and broccoli are infected, the heads deteriorate and there is a complete loss of marketability. Secondary soft-rotting organisms can infect stored cabbage that has been affected by Alternaria Leaf Spot by entering through symptomatic lesions. Alternaria Leaf Spot diseases that affect Brassica species are caused by the pathogens Alternaria brassicae and Alternaria brassicicola.

<span class="mw-page-title-main">Viral diseases of potato</span> Group of diseases affecting potato plants

Viral diseases of potato are a group of diseases caused by different types of Viruses that affect potato crops worldwide and, although they do not affect human or animal health since they are viruses that only infect vegetables, they are a source of great economic losses annually. About 28 viruses have been reported infecting potato crops. However, potato virus X (PVX), potato virus Y (PVY), and potato leafroll virus (PLRV) are the most important viruses worldwide. Some others are of economic importance only in some regions. Such is the case of potato virus M (PVM) in some Asian and European countries.

References

  1. 1 2 Hibi T, Furuki I, 1985. Melon necrotic spot virus. Wellesbourne, UK: Association of Applied Biologists: Descriptions of PlantsViruses no. 302
  2. Tesoriero, Len. Preventing New Diseases - Melon Necrotic Spot Virus. Orange: Government of New South Wales - Department of Primary Industries, 1 Oct. 2013. Pdf.
  3. Herrera-Vásquez JA, Cebrián MC, Roselló JA, Córdoba-Sellés C, Jordá C, 2007. Molecular variability among isolates of Melon necrotic spot virus (MNSV) from Spain, Mexico and Central America. In: XIII International Congress on Molecular Plant-Microbe Interactions. Italy: Sorrento, 281.
  4. 1 2 3 Campbell, R. (1996). "Vector-Assisted Seed Transmission of Melon Necrotic Spot Virus in Melon". Phytopathology. 86 (12): 1294. doi:10.1094/Phyto-86-1294.
  5. Coudriet, D.L., A.N. Kishaba, and I.E. Carrol. 1979. transmission of melon necrotic spot virus in muskmelons by cucumber beetles.. J. Econ. Entomol. 72:560-561.
  6. Gonzalez-Garza R, Gumpf DJ, Kishaba AN and Bohn GW. (1979) Identification, seed transmission and host range pathogenicity of a California isolate of melon necrotic spot virus. Phytopathology 69:340-345.
  7. EPPO/CABI (1997a) Diabrotica barberi and Diabrotica virgifera. In Quarantine Pests for Europe (2nd ed), pp. 233-237. CAB International, Wallingford (GB).
  8. Kishi K. 1966 Necrotic spot of melon, a new virus disease. Ann. Phytopathol. Soc. Japan. 32:138-144.
  9. Mallor Giménez, C.; Álvarez Álvarez, J. M. A.; Arteaga, M. L. (2003). "Inheritance of resistance to systemic symptom expression of Melon necrotic spot virus (MNSV) in Cucumis melo L. 'Doublon'". Euphytica. 134 (3): 319. doi:10.1023/B:EUPH.0000004969.95036.1d. S2CID   41736537.
  10. Herrera-Vásquez, J. A., M. C. Córdoba-Sellés, M. C. Cebrián, A. Alfaro-Fernández, and C. Jordá. "Seed Transmission Ofand Efficacy of Seed-disinfection Treatments." Plant Pathology 58.3 (2009): 436-42. Web. 12 Nov. 2014.
  11. Altschul, S.; Madden, T. L.; Schäffer, A. A.; Zhang, J.; Zhang, Z.; Miller, W.; Lipman, D. J. (1997). "Gapped BLAST and PSI-BLAST: A new generation of protein database search programs". Nucleic Acids Research. 25 (17): 3389–3402. doi:10.1093/nar/25.17.3389. PMC   146917 . PMID   9254694.
  12. "Coudriet, D.L., A.N. Kishaba, and G.W. Bohn. 1981. Inheritance of resistance to muskmelon necrotic spot virus in a melon aphid-resistant breeding line of muskmelon. J. Am. Soc. Hort. Sci. 106:709-791."
  13. Tomlinson, J. A.; Thomas, B. J. (1986). "Studies on melon necrotic spot virus disease of cucumber and on the control of the fungus vector (Olpidium radicale)". Annals of Applied Biology. 108: 71–80. doi:10.1111/j.1744-7348.1986.tb01967.x.
  14. Ohki, T.; Sako, I.; Kanda, A.; Mochizuki, T.; Honda, Y.; Tsuda, S. (2008). "A New Strain of Melon necrotic spot virusthat is Unable to Systemically Infect Cucumis melo". Phytopathology. 98 (11): 1165–70. doi: 10.1094/PHYTO-98-11-1165 . PMID   18943404.