Verticillium dahliae

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Verticillium dahliae
Symptoms of
sunflower
Scientific classification
Kingdom:
Fungi
Division:
Ascomycota
Class:
Sordariomycetes
Subclass:
Hypocreomycetidae
Order:
Hypocreales
Family:
Incertae sedis
Genus:
Verticillium
Species:
V. dahliae
Binomial name
Verticillium dahliae
Kleb., (1913)
Synonyms

Verticillium albo-atrum var. chlamydosporale
Verticillium albo-atrum var. dahliae
Verticillium albo-atrum var. medium
Verticillium dahliae f. chlamydosporale
Verticillium dahliae f. medium
Verticillium ovatum
Verticillium tracheiphilum

Verticillium dahliae is a fungal

plant pathogen. It causes verticillium wilt in many plant species, causing leaves to curl and discolor. It may cause death in some plants. Over 400 plant species are affected by Verticillium complex.[1]

Management

Verticillium dahliae has a wide host range and can persist as

microsclerotia in the soil for years, so management via fallowing or crop rotation generally has little success.[2] The exception to this is rotation using broccoli, which has been shown to decrease Verticillium severity and incidence in cauliflower fields.[3] This is likely due to the production of allyl isothiocyanate in broccoli, which can suppress the growth of plant pathogenic fungi.[4]

Seed choice may reduce disease presence. Purchasing seed stock from certified Verticillium-free growers and utilizing resistant or partially resistant cultivars can decrease disease incidence. Even resistant cultivars may show symptoms if the field has a high concentration of Verticillium, so site selection is still essential to minimizing disease incidence.[2]

Using fertilizers high in nitrogen and overwatering crops, especially early in the season, may increase disease incidence, so proper fertilizer ratios and drip irrigation are recommended.[5] Following harvest, burning crop residues will limit the amount of Verticillium that can enter the soil and overwinter.[2]

Hosts and symptoms

There are many strains of Verticillium dahliae which are categorized into

host specific
, as a species it has a wide range.

Verticillium dahliae has a very wide host range, affecting over 300 plant species. Some susceptible crops include Brussels sprouts, cabbage, eggplant, cucumbers, mint, pepper, potatoes, pumpkin, spinach, tomato, watermelon, honeydew, and cantaloupe. Of these, tomato, potato, and eggplant have resistant or tolerant varieties.[6]

Symptoms of this disease are seen throughout the plant. Leaves may have abnormal coloration, necrotic areas, wilt, and/or fall off the plant. The stem may have discolored vascular tissue, exhibit rosetting (shortened internodes of the plant caused by reduced growth, resulting in a rosette-like appearance),[7] and/or be stunted. Early senescence and dieback may also occur.[8]

Microsclerotia can be seen under a lens as small black structures in the vasculature of living and dead plants. This feature can be used to distinguish V. dahliae from V. albo-atrum, the other verticillium wilt pathogen.[2]

Disease cycle

Verticillium dahliae invades the host plant via natural wounds or by penetrating the root tissue. Following entry, the pathogen enters the

saprophytically in the soil. Microsclerotia can be spread via wind and rain, resulting in infection of previously pathogen-free fields.[9] Additionally, the disease can spread locally from the roots of affected plants to healthy plants, live in the vascular tissue of some resistant species, and spread via wind from host leaf tissue.[10]

With this pathogen's ability to survive saprophytically or form resting spores that can survive for over a decade, once a site is infected, it will most likely never be Verticillium-free again.[10]

Recombination

V. dahliae, a fungus in the division Ascomycota, has a strongly clonal population structure. Recombination events have occurred between different clonal lineages, and less frequently within lineages.[11] Two mating types have been identified. Homologs of eight meiosis specific genes are present in the V. dahliae genome. These findings suggest that the capability for meiotic sexual reproduction has been adaptively maintained in the clonal lineages of V. dahliae, and can occasionally be expressed as recombination between genetic markers. Perhaps, as suggested by Wallen and Perlin[12] for Ascomycota fungi generally, in V. dahliae homologous recombination during sexual reproduction functions to repair DNA damage, especially under stressful conditions.

References

  1. ^ "Verticillium wilt". www.apsnet.org. 2005. Retrieved 2016-01-18.
  2. ^
    doi:10.1094/phi-i-2000-0801-01
    . Retrieved 2018-12-09.
  3. ISSN 0008-0845
    .
  4. ISSN 0031-949X
    .
  5. ^ University of California Agriculture & Natural Resources (2018). "UC Pest Management Guidelines: Verticillum Wilt".
  6. ^ Douglas, S (2008). "Verticillium Wilt of Vegetables and Herbaceous Ornamentals" (PDF). www.ct.gov. Retrieved 2018-12-09.
  7. ^ "Morphological Symptoms of Plant Diseases | Botany". Botany Library. 2017-12-20. Retrieved 2023-02-22.
  8. ^ "Verticillium dahliae (verticillium wilt)". www.cabi.org. Retrieved 2018-12-09.
  9. ^ University of Illinois Extension (1997). "Verticillium Wilt Disease" (PDF). m.extension.illinois.edu. Retrieved 2018-12-09.
  10. ^ a b Brazee, N (2015-03-06). "Verticillium Wilt". Center for Agriculture, Food and the Environment. Retrieved 2018-12-09.
  11. PMID 25181515
    .
  12. PMID 29619017
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Verticillium_dahliae&oldid=1194832798"