Thecaphora frezzii | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Basidiomycota |
Class: | Ustilaginomycetes |
Order: | Urocystidales |
Family: | Glomosporiaceae |
Genus: | Thecaphora |
Species: | T. frezzii |
Binomial name | |
Thecaphora frezzii J.M. Carranza and J.C. Lindquist (1962) | |
Thecaphora frezzii, commonly referred to as peanut smut, is a species of smut fungus of the genus Thecaphora and the family Glomosporiaceae. It is a basidiomycete fungus that infects peanut plants (Arachis hypogaea). [1] It is currently only found in South America, more specifically in Argentinian peanut farms. [2]
Thecaphora frezzii was described by J.M. Carranza and J.C. Lindquist in 1962. [3] It was originally spelled as "frezii" but was later changed to "frezzii." [4]
An infected host's pod will have hypertrophic cells in the form of galls and a spongy consistency. [5] The cells of the grains inside the pods are destroyed and replaced by reddish-brown teliospores. [5] Something characteristic of all Thecaphora species is that they all produce sori in the host plant. [6] For T. frezzii, these sori are produced on the peanut seeds and are composed of 1 to 10 tightly bound spores. [6]
Thecophora frezzii is a biotrophic obligate parasite of peanut plants. [1] It is monocyclic, so an infection cycle occurs once per growing season. [1] The fungus causes a partial or total destruction of the peanut fruit. [2] Throughout the biological cycle of the fungus, there are three main structures: teliospores, basidiospores, and hyphae.
The teliospores are present during the state of dormancy and act as resistance structures. [7] [2] They have thick walls allowing the fungus to survive in the soil and crop residue until germination. [7] Teliospores germinate in response to the plant root exudates, therefore infection occurs once the peanut peg enters the soil. [4] Teliospores disperse most commonly via wind or machinery when peanuts are harvested and remain dormant until germination is triggered. [8] [7]
Following the germination of teliospores, the probasidum forms. The probasidium has two haploid nuclei which fuse to form a diploid nucleus. [2] From this nucleus, the basidium arises, which forms basidiospores via meiosis. [2] During basidiospore germination, compatible haploid germ tubes fuse. [2]
Germination of the basidiospores leads to the formation of a dikaryotic mycelium, which is the infection structure of Thecaphora frezzii. [2] The mycelium infects the host by penetrating the gynophore. [8] It uses effectors to suppress the host's immune responses to insure successful penetration and infection. [8]
Thecaphora frezzii is only found in South America. Cases of peanut smut on domesticated peanuts are only reported in Argentina, while wild peanuts were found to be infected in other parts of the continent. [1] The fungus never breaches to the surface and remains in humid soils. [2] Prevalence of the fungus is higher in soils in which crop rotation is rare and peanut farming has been the only usage for an extended period. [2]
T. frezzii was first detected in 1955 in the Córdoba Province. [9] By 2011, the fungus had reached 100% prevalence in production fields, with disease incidence reaching up to 52% of plants [10] . [9] [11] In 2016, the reported total yield loss was equal to $14,151,800 for Argentina. [2]
Many methods of management have been attempted but have proven to be ineffective against the fungus. [12] The most effective method reported is cultivating resistant strains of peanut. [11] While cultivated peanut plants have low genetic diversity, T. frezzii has high genetic variability making it difficult to cultivate resistant plants. [9]
Recent studies have begun testing biological control options by using other organisms such as bacteria or fungi to control the fungus. One organism that has been tested in Argentina is Trichoderma harazianum [13] .
Basidiomycota is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basidiomycota includes these groups: agarics, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, chanterelles, earth stars, smuts, bunts, rusts, mirror yeasts, and Cryptococcus, the human pathogenic yeast.
Rusts are fungal plant pathogens of the order Pucciniales causing plant fungal diseases.
The smuts are multicellular fungi characterized by their large numbers of teliospores. The smuts get their name from a Germanic word for 'dirt' because of their dark, thick-walled, and dust-like teliospores. They are mostly Ustilaginomycetes and comprise seven of the 15 orders of the subphylum. Most described smuts belong to two orders, Ustilaginales and Tilletiales. The smuts are normally grouped with the other basidiomycetes because of their commonalities concerning sexual reproduction.
Karnal bunt is a fungal disease of wheat, durum wheat, and triticale. The smut fungus Tilletia indica, a basidiomycete, invades the kernels and obtains nutrients from the endosperm, leaving behind waste products with a disagreeable odor that makes bunted kernels too unpalatable for use in flour or pasta. While Karnal bunt generally does not lead to devastating crop losses, it has the potential to dramatically decrease yield, and poses additional economic concerns through quarantines which limit the export of suspected infectious wheat products from certain areas, including the U.S. Several chemical control methods exist for Karnal bunt of wheat, but much work remains to be done in identifying resistant host varieties.
Sugarcane smut is a fungal disease of sugarcane caused by the fungus Sporisorium scitamineum. The disease is known as culmicolous, which describes the outgrowth of fungus of the stalk on the cane. It attacks several sugarcane species and has been reported to occur on a few other grass species as well, but not to a critical amount. The most recognizable characteristic of this disease is a black or gray growth that is referred to as a "smut whip". Resistance to sugarcane smut is the best course of action for management, but also the use of disease free seed is important. On smaller scale operations treatments using hot water and removing infected plants can be effective. The main mode of spore dispersal is the wind but the disease also spreads through the use of infected cuttings. Sugarcane smut is a devastating disease in sugarcane growing areas globally.
Common bunt, also known as hill bunt, Indian bunt, European bunt, stinking smut or covered smut, is a disease of both spring and winter wheats. It is caused by two very closely related fungi, Tilletia tritici and T. laevis.
Loose smut of barley is caused by Ustilago nuda. It is a disease that can destroy a large proportion of a barley crop. Loose smut replaces grain heads with smut, or masses of spores which infect the open flowers of healthy plants and grow into the seed, without showing any symptoms. Seeds appear healthy and only when they reach maturity the following season is it clear that they were infected. Systemic fungicides are the major control method for loose smut.
Gymnosporangium juniperi-virginianae is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples (Malus) and eastern red cedar coexist, cedar apple rust can be a destructive or disfiguring disease on both the apples and cedars. Apples, crabapples, and eastern red cedar are the most common hosts for this disease. Similar diseases can be found on quince and hawthorn and many species of juniper can substitute for the eastern red cedars.
Tilletia caries is a basidiomycete that causes common bunt of wheat. The common names of this disease are stinking bunt of wheat and stinking smut of wheat. This pathogen infects wheat, rye, and various other grasses. T. caries is economically and agriculturally important because it reduces both the wheat yield and grain quality.
Urocystis agropyri is a fungal plant pathogen that causes flag smut on wheat.
Puccinia menthae is a fungal plant pathogen that causes rust on mint plants. It was originally found on the leaves of Mentha aquatica.
Sporisorium sorghi, commonly known as sorghum smut, is a plant pathogen that belongs to the Ustilaginaceae family. This fungus is the causative agent of covered kernel smut disease and infects sorghum plants all around the world such as Sorghum bicolor (sorghum), S. sudanense, S. halepense and Sorghumvulgare var. technichum (broomcorn). Ineffective control of S. sorghi can have serious economic and ecological implications.
Sporisorium reilianum Langdon & Full., (1978), previously known as Sphacelotheca reiliana, and Sporisorium reilianum, is a species of biotrophic fungus in the family Ustilaginaceae. It is a plant pathogen that infects maize and sorghum.
Thecaphora is a genus of basidiomycote fungus which contains several species of plant pathogens. The widespread genus contained about 57 species in 2008. and held 61 species in 2020.
Tilletia horrida, rice kernel smut, caryopsis smut, black smut, or grain smut, is a fungal rice disease believed to only affect the Oryza genus. It presents as a partial bunt.
Puccinia horiana is a species of fungus that causes chrysanthemum white rust, is a disease of plant species of the genus Chrysanthemum.
Salmacisia is a fungal genus in the family Tilletiaceae. It is a monotypic genus, containing the single species Salmacisia buchloëana, first described as Tilletia buchloëana in 1889, and renamed in 2008. Plants infected by the fungus undergo a phenomenon known as "parasitically induced hermaphroditism", whereby ovary development is induced in otherwise male plants. Because of the pistil-inducing effects of the fungus, the authors have named the species pistil smut; it is the only species in the order Tilletiales known to have hermaphroditic effects.
Microbotryum violaceum is a host-specific anther smut (fungus) disease that infects Silene latifolia and sterilizes the host plant. When infected with this disease, the flowers generate pathogenic spores, which can then be transferred to other plants by pollinating insects. Therefore, this disease is sometimes classified as a sexually transmitted infection.
Melampsora amygdalinae is a fungal pathogen and part of the division Basidiomycota. It is known as a rust fungus that is host specific. M. amygdalinae commonly infects willows of the genus Salix. This fungus was first discovered in 1909 by Heinrich Klebahn who was a professor of soil biology in Hamburg. Neimi at el. explain how the pathogen occurs throughout the whole distribution of the host, and the small natural populations are an area of interest. This rust fungus is annual and autoecious, which references the fungus spending its entire life in a single host.
Puccinia sorghi, or common rust of maize, is a species of rust fungus that infects corn and species from the plant genus Oxalis.