''Ganoderma orbiforme'' most commonly known as ''G. boninense'' or just ''Ganoderma'' in oil palm pathology is a species of polypore fungus that is widespread across southeast Asia. It is a

plant pathogen Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomyc ...

that causes basal stem rot, a disease of the African oil palm (''Elaeis guineensis''). The fungus was first described scientifically in 1838 by

Elias Magnus Fries Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. Career Fries was born at Femsjö (Hylte Municipality), Småland, the son of the pastor there. He attended school in Växjö. He acquired ...

from collections made in

Guinea Guinea ( ),, fuf, 𞤘𞤭𞤲𞤫, italic=no, Gine, wo, Gine, nqo, ߖߌ߬ߣߍ߫, bm, Gine officially the Republic of Guinea (french: République de Guinée), is a coastal country in West Africa. It borders the Atlantic Ocean to the we ...

Leif Ryvarden Leif Randulff Ryvarden (born 9 August 1935) is a Norwegian mycologist. Early life and education Leif Ryvarden was born in Bergen as a son of Einar Norberg Johansen (1900–1959) and Hjørdis Randulff (1912–1975). He finished his secondary edu ...

transferred it to the genus ''

Ganoderma ''Ganoderma'' is a genus of polypore fungi in the family Ganodermataceae that includes about 80 species, many from tropical regions. They have a high genetic diversity and are used in traditional Asian medicines. ''Ganoderma'' can be differenti ...

'' in 2000. In addition to its type locality, the fungus has also been collected from the Bonin Islands in the Pacific, and from Venezuela and Puerto Rico.

Transmission

''G. orbiforme'' is not a

soil borne pathogen A soil borne pathogen is a disease-causing agent which lives both in soil and in a plant host, and which will tend to infect undiseased plants which are grown in that soil. Common soil borne pathogens include ''Fusarium'', ''Pythium'', ''Rhizoctoni ...

, meaning it does not grow in soil and does not infiltrate from soil and into the root system. It is however also not killed by soil, and will reside in dead, buried palm trunk material. This has especially been observed when ''

Oryctes rhinoceros The Asiatic rhinoceros beetle, coconut rhinoceros beetle or coconut palm rhinoceros beetle, (''Oryctes rhinoceros'') is a species of rhinoceros beetle of the family Scarabaeidae. ''O. rhinoceros'' attacks the developing fronds of raffia, coconut, ...

''-infested material was buried.

Infection

''G. orbiforme'' has a

hemibiotrophic Hemibiotrophs are the spectrum of plant pathogens, including bacteria, oomycete and a group of plant pathogenic fungi that keep its host alive while establishing itself within the host tissue, taking up the nutrients with brief biotrophic-like ph ...

lifestyle in ''E. guineensis''. During an invasion, ''E. guineensis'' roots stockpile

salicylic acid Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Substance ...

, which is a signal to downregulate its own expression of

ascorbate oxidase In enzymology, a L-ascorbate oxidase () is an enzyme that catalyzes the chemical reaction :2 L-ascorbate + O2 \rightleftharpoons 2 dehydroascorbate + 2 H2O Thus, the two substrates of this enzyme are L-ascorbate and O2, whereas its two products ...

and

ascorbate peroxidase Ascorbate peroxidase (or L-ascorbate peroxidase, APX) () is an enzyme that catalyzes the chemical reaction :L-ascorbate + H2O2 \rightleftharpoons dehydroascorbate + 2 H2O It is a member of the family of heme-containing peroxidases. Heme peroxi ...

. AO and AP are reactive oxygen species scavengers, and so the total effect is to increase ROS production. This entire pathway was found by Ho ''et al.'', 2016. Increased ROS is effective against hemibiotrophs but counterproductive against

necrotroph A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...

Genetics

Microsatellite A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. ...

markers have been developed to help identify the fungus and study the

genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...

of ''G. orbiforme''.

Research

Water agar is usable for isolation of this fungus, and is the simplest and cheapest. CABI provides research and

technique Technique or techniques may refer to: Music * The Techniques, a Jamaican rocksteady vocal group of the 1960s *Technique (band), a British female synth pop band in the 1990s * ''Technique'' (album), by New Order, 1989 * ''Techniques'' (album), by M ...

information for lab work with this pathogen.

References

External links

* * {{Taxonbar, from=Q5521450 Fungi described in 1838 Fungi of Africa Fungi of Asia Fungi of South America Fungal plant pathogens and diseases Ganoderma Taxa named by Elias Magnus Fries Pests of oil palm