Fusarium oxysporum
Encyclopedia
Fusarium oxysporum Schlecht. as emended by Snyder and Hansen comprises all the species, varieties and forms recognized by Wollenweber and Reinking within an infrageneric grouping called section Elegans. While the species, as defined by Snyder and Hansen, has been widely accepted for more than 50 years, more recent work indicates this taxon
is actually a genetically heterogeneous polytypic morphospecies whose strains represent some of the most abundant and widespread microbes of the global soil microflora , although this last statement has not been proven or supported by actual data. These remarkably diverse and adaptable fungi have been found in soils ranging from the Sonoran Desert, to tropical and temperate forests, grasslands and soils of the tundra. F. oxysporum strains are ubiquitous soil inhabitants that have the ability to exist as saprophytes
, and degrade lignin
and complex carbohydrates associated with soil debris. They are also pervasive plant endophytes that can colonize plant roots and may even protect plants or be the basis of disease suppression. Although the predominant role of these fungi in native soils may be as harmless or even beneficial plant endophytes or soil saprophytes
, many strains within the F. oxysporum complex are pathogenic to plants, especially in agricultural settings.
Pathogenic strains of F. oxysporum have been studied for more than 100 years. The host range of these fungi is extremely broad, and includes animals, ranging from arthropods to humans, as well as plants, including a range of both gymnosperms and angiosperms. While collectively, plant pathogenic F. oxysporum strains have a broad host range, individual isolates usually cause disease only on a narrow range of plant species. This observation has led to the idea of "special form" or forma speciales in F. oxysporum. Formae speciales have been defined as "...an informal rank in Classification.....used for parasitic fungi characterized from a physiological standpoint (e.g. by the ability to cause disease in particular hosts) but scarcely or not at all from a morphological
standpoint. As a category, forma specialis is mentioned in, but not regulated by, the International Code of Botanical Nomenclature and sometimes it has been inconsistently applied. Exhaustive host range studies also have been conducted for relatively few formae speciales or F. oxysporum. For more information on Fusarium oxysporum as a plant pathogen, see Fusarium wilt
.
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
is actually a genetically heterogeneous polytypic morphospecies whose strains represent some of the most abundant and widespread microbes of the global soil microflora , although this last statement has not been proven or supported by actual data. These remarkably diverse and adaptable fungi have been found in soils ranging from the Sonoran Desert, to tropical and temperate forests, grasslands and soils of the tundra. F. oxysporum strains are ubiquitous soil inhabitants that have the ability to exist as saprophytes
Saprophytes
Saprophytes may refer to*Saprotroph, a term used for organisms which obtain nutrients from dead organic matter...
, and degrade lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...
and complex carbohydrates associated with soil debris. They are also pervasive plant endophytes that can colonize plant roots and may even protect plants or be the basis of disease suppression. Although the predominant role of these fungi in native soils may be as harmless or even beneficial plant endophytes or soil saprophytes
Saprophytes
Saprophytes may refer to*Saprotroph, a term used for organisms which obtain nutrients from dead organic matter...
, many strains within the F. oxysporum complex are pathogenic to plants, especially in agricultural settings.
Pathogenic strains of F. oxysporum have been studied for more than 100 years. The host range of these fungi is extremely broad, and includes animals, ranging from arthropods to humans, as well as plants, including a range of both gymnosperms and angiosperms. While collectively, plant pathogenic F. oxysporum strains have a broad host range, individual isolates usually cause disease only on a narrow range of plant species. This observation has led to the idea of "special form" or forma speciales in F. oxysporum. Formae speciales have been defined as "...an informal rank in Classification.....used for parasitic fungi characterized from a physiological standpoint (e.g. by the ability to cause disease in particular hosts) but scarcely or not at all from a morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
standpoint. As a category, forma specialis is mentioned in, but not regulated by, the International Code of Botanical Nomenclature and sometimes it has been inconsistently applied. Exhaustive host range studies also have been conducted for relatively few formae speciales or F. oxysporum. For more information on Fusarium oxysporum as a plant pathogen, see Fusarium wilt
Fusarium wilt
Fusarium wilt is a common vascular wilt fungal disease, exhibiting symptoms similar to Verticillium wilt. The pathogen that causes Fusarium wilt is Fusarium oxysporum . The species is further divided into forma specialis based on host plant.-Hosts and symptoms:The fungal pathogen Fusarium...
.
Formae speciales (Special Forms)
- Fusarium oxysporum f.sp. albedinisFusarium oxysporum f.sp. albedinisFusarium oxysporum f.sp. albedinis is a fungal plant pathogen that causes a disease known as Bayoudh disease or fusarium wilt primarily on dates.-External links:* *...
- Fusarium oxysporum f.sp. asparagiFusarium oxysporum f.sp. asparagiFusarium oxysporum f.sp. asparagi is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. batatasFusarium oxysporum f.sp. batatasFusarium oxysporum f.sp. batatas is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. betaeFusarium oxysporum f.sp. betaeFusarium oxysporum f.sp. betae is a destructive fungal plant pathogen. It causes cabbage yellows or cabbage wilt, characterized by yellowing and dwarfing.-External links:* *...
- Fusarium oxysporum f.sp. cannabisFusarium oxysporum f.sp. cannabisFusarium oxysporum f.sp. cannabis is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. cepae
- Fusarium oxysporum f.sp. cicerisFusarium oxysporum f.sp. cicerisFusarium oxysporum f.sp. ciceris is a fungal plant pathogen that causes fusarium wilt of chickpea.-Description:Fusarium oxysporum is a common soil inhabitant and produces three types of asexual spores; macroconidia, microconidia and chlamydospores....
- Fusarium oxysporum f.sp. citriFusarium oxysporum f.sp. citriFusarium oxysporum f.sp. citri is a fungus which reproduces by cell fission. It is a well known plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. coffeaFusarium oxysporum f.sp. coffeaFusarium oxysporum f.sp. coffea is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. cubenseFusarium oxysporum f.sp. cubenseFusarium oxysporum f.sp. cubense is a fungal plant pathogen that causes Panama disease of banana , also known as fusarium wilt of banana.-Overview:...
- Fusarium oxysporum f.sp. cyclaminisFusarium oxysporum f.sp. cyclaminisFusarium oxysporum f.sp. Cyclaminis is a fungal plant pathogen.-External links:**...
- Fusarium oxysporum f.sp. herbemontis
- Fusarium oxysporum f.sp. dianthiFusarium oxysporum f.sp. dianthiFusarium oxysporum f.sp. dianthi is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. lentisFusarium oxysporum f.sp. lentisFusarium oxysporum f.sp. lentis is a fungal plant pathogen.-External links:* * vdfvdfg fv...
- Fusarium oxysporum f.sp. liniFusarium oxysporum f.sp. liniFusarium oxysporum f.sp. lini is a fungal plant pathogen. Among the diseases it causes is flax wilt.-External links:* *...
- Fusarium oxysporum f.sp. lycopersiciFusarium oxysporum f.sp. lycopersiciFusarium oxysporum f.sp. lycopersici is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. medicaginisFusarium oxysporum f.sp. medicaginisFusarium oxysporum f.sp. medicaginis is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. melonis
- Fusarium oxysporum f.sp. nicotianae
- Fusarium oxysporum f.sp. niveum
- Fusarium oxysporum f.sp. passiflorae
- Fusarium oxysporum f.sp. phaseoli
- Fusarium oxysporum f.sp. pisiFusarium oxysporum f.sp. pisiFusarium oxysporum f.sp. pisi is a fungal plant pathogen, endemic to Moldova.-External links:* *...
- Fusarium oxysporum f.sp. radicis-lycopersiciFusarium oxysporum f.sp. radicis-lycopersiciFusarium oxysporum f.sp. radicis-lycopersici is a fungal plant pathogen.-External links:* *...
- Fusarium oxysporum f.sp. ricini
- Fusarium oxysporum f.sp. strigae
- Fusarium oxysporum f.sp. tuberosi
- Fusarium oxysporum f.sp. tulipae
- Fusarium oxysporum f.sp. vasinfectumFusarium oxysporum f.sp. vasinfectumFusarium oxysporum f.sp. vasinfectum is a fungal plant pathogen.-External links:* *...
Patents relating to the management of Fusarium oxysporum
A number of recent patents specifically describe effective treatments of Fusarium oxysporum, reflecting its widespread importance as an agricultural pest.- US 5,614,188: two strains of BacillusBacillusBacillus is a genus of Gram-positive, rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species...
in a composition of chitin and lime used to fight Fusarium in the soil. - US 2004/136964 A1: Trichoderma asperellumTrichodermaTrichoderma is a genus of fungi that is present in all soils, where they are the most prevalent culturable fungi. Many species in this genus can be characterized as opportunistic avirulent plant symbionts.-Species:...
mixed into container media (such as peat). - US 4,714,614: a strain of Pseudomonas putidaPseudomonas putidaPseudomonas putida is a gram-negative rod-shaped saprotrophic soil bacterium. Based on 16S rRNA analysis, P. putida has been placed in the P. putida group, to which it lends its name....
in combination with an iron chelating agent (such as EDTA). - US 4988586: any of six types of bacteria that degrade fusaric acid, a toxin that damages plants and furthers infection.
- US 6100449 and WO 1996/032007 A1: a small genomic region (I2C) conferring resistance in transgenic tomatoes.
- US 2003/131376 A1: use of transgenic plants expressing enzymes capable of destroying Fusarium cell walls.
- US 4006265: spraying of crops with hydrogen peroxide to reduce the effect of contamination by Fusarium toxins.
- WO 2005/074687 A1: cure of infected plants by spraying with natamycin or other polyene antibiotics.