Phaeocryptopus Gaeumannii on:
[Wikipedia]
[Google]
[Amazon]
''Nothophaeocryptopus gaeumannii'' is a species of
Abstract
/ref>
fungus
A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...
that occurs as an endophyte
An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life cycle without causing apparent disease. Endophytes are ubiquitous and have been found in all species of plants studied to date; h ...
inside the needles of Douglas-fir
The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three ...
trees. It is responsible for causing the nonlethal disease known as Swiss needle cast, which results in needle loss and reduction in growth in Douglas-fir.
Traditionally, it has been considered part of family Venturiaceae
The Venturiaceae are a family of fungi in the order Pleosporales. Several of the species in this family are plant pathogens.
List of genera
As accepted by GBIF;
*''Acantharia'' (7)
*''Antennaria'' (2)
*''Antennularia'' (1)
*'' Anungitea'' ...
, but molecular studies have confirmed its placement in Mycosphaerellaceae
The Mycosphaerellaceae are a family of sac fungi. They affect many common plants, such as eucalyptus
''Eucalyptus'' () is a genus of over seven hundred species of Flowering plant, flowering trees, shrubs or Mallee (habit), mallees in the Myrt ...
. Three different lineages of ''N. gaeumannii'' are known, each with distinct ecological, morphological, and molecular characteristics.
Distribution
This species of fungus is native to western North America. Remarkably, the disease’s name, Swiss needle cast, arises from the fact that the fungus was first discovered in Switzerland in the 1930s where it was found to be causing disease in plantations of Douglas-fir. It has since been introduced almost everywhere Douglas-fir is grown, and is now widespread inEurope
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...
, New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...
, and Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...
. Although the fungus had been known in North America almost since its first discovery, for decades it was not considered to cause disease in its native range, and was largely ignored there until an outbreak occurred in the 1980s and 1990s.
Ecology
''N. gaeumannii'' is anobligate {{wiktionary, obligate
As an adjective, obligate means "by necessity" (antonym '' facultative'') and is used mainly in biology in phrases such as:
* Obligate aerobe, an organism that cannot survive without oxygen
* Obligate anaerobe, an organism tha ...
endophyte
An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life cycle without causing apparent disease. Endophytes are ubiquitous and have been found in all species of plants studied to date; h ...
of Douglas-fir needles. In the spring, ascospores
An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or ...
infect young needles, briefly growing epiphytically
An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...
before the hyphae
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Structure
A hypha consists of one or ...
penetrate the needle tissue via stomata. The fungus then spends most of its life cycle
Life cycle, life-cycle, or lifecycle may refer to:
Science and academia
* Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring
* Life-cycle hypothesi ...
growing intercellularly inside the needle. After maturing for approximately nine months, the fungus produces pseudothecia
An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mos ...
which emerge from the stomata of the needle, dispersing new spores the following spring.
Disease
Normally, when low in abundance, ''N. gaeumannii'' is a relatively benign symbiont of Douglas-fir needles. However, when the fungus is abundant it is responsible for causing the nonlethal disease known as Swiss needle cast. It produces small, spherical black fruiting bodies (pseudothecia
An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mos ...
) which obstruct the needle’s stomatal openings. The pseudothecia block gas exchange into and out of the needle, which prevents photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
in heavily infected needles. This causes yellowing (chlorosis) of the needles, with eventual necrosis and premature needle-drop. In some heavily infected stands of trees, the only needles remaining are those of the current year, in which the disease has not yet had time to fully develop.
Due to the reduced photosynthesis caused by needle loss, the tree experiences a diminished rate of growth by 52% or more. Increased disease severity tends to occur in climates with mild winters and high humidity where the fungus thrives, and appears to be increasing in severity as a result of climate change./ref>
Gallery
References
External links
* {{Taxonbar, from=Q10625790 Venturiaceae Fungal conifer pathogens and diseases Fungi described in 1936 Fungi of Europe Fungi of North America Fungus species