psychrophilic
Psychrophiles or cryophiles (adj. ''psychrophilic'' or ''cryophilic'') are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from to . They have an optimal growth temperature at . They are found in ...
plant pathogen infecting
barley
Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley pr ...
,
rye
Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is a member of the wheat tribe (Triticeae) and is closely related to both wheat (''Triticum'') and barley (genus ''Hordeum''). Rye grain is u ...
and
wheat
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...
.
Physiology
Temperature
Minimum growth temperature is below . Optimal growth range is . Maximum growth temperature , whereupon irregular mycelial growth occurs and oxygen consumption is far above healthy level; does not survive above. Sclerotia germination optimal at four weeks of daily thermal cycles of followed by . Frost is necessary during life cycle.
Enzymes
Produces
polygalacturonase
Endo-polygalacturonase (EC 3.2.1.15, pectin depolymerase, pectolase, pectin hydrolase, and poly-α-1,4-galacturonide glycanohydrolase; systematic name (1→4)-α-D-galacturonan glycanohydrolase (endo-cleaving)) is an enzyme that hydrolyzes the α- ...
; variant with maximum activity between and only 30% of max activity at . Activity preserved at beyond two years, but inactivated by overnight at room temperature, or by 30 minutes of . A crude extract of cultured bran contained a particular low mass molecule which maintained activity at low temperature.
Antifreeze proteins
Necessitated by its lifestyle, ''S. borealis'' produces its own
antifreeze protein
Antifreeze proteins (AFPs) or ice structuring proteins refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water. AFPs bind to small i ...
Upon the spring snowmelt, wet leaves develop ''S. borealis'' growth.
Sclerotia
A sclerotium (; (), is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant until favor ...
and
mycelia
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates in ...
grow on sheaths, crowns, surfaces, and interiors of leaves. Has dramatically more growth - and damage to its hosts - in growth seasons following winters with greater depth of soil freezing but less snow cover. ''S. borealis'' is very soil-frost-dependent.
Morphology
Sclerotia are long and wide when formed (i.e. before desiccation).
Apothecia
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 mo ...
cup-shaped pale yellow to pale brown, cup diameter , stalks high.
Mycelia gray.
Hosts
Grass
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...
es and
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s. Economically significant grasses include
winter cereal
Winter cereals, also called winter grains, fall cereals, fall grains, or autumn-sown grains, are Biennial plant, biennial cereals, cereal Crop, crops sown in the autumn. They germinate before winter comes, may partially grow during mild winters or ...
s and
forage
Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...
s.
Conifer
Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...
seedling
A seedling is a young sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (embry ...
s in the
Volga-Ural
Idel-Ural ( tt-Cyrl, Идел-Урал, translit=Idel-Üral, russian: Идель-Урал), literally Volga-Ural, is a historical region in Eastern Europe, in what is today Russia. The name literally means ''Volga-Urals'' in the Tatar language. T ...
region of Russia.
Distribution
''S. borealis'' is found in
cool temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
Arctic
The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
, including
northern Japan
Japan is an archipelagic country comprising a stratovolcanic archipelago over along the Pacific coast of East Asia. It consists of 6,852 islands. The five main islands are Hokkaido, Honshu, Kyushu, Shikoku and Okinawa. There are 6,847 remote ...
,
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
. Specifically including Arctic areas of
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
, the
Yukon
Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...
,
Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
,
Finnmark
Finnmark (; se, Finnmárku ; fkv, Finmarku; fi, Ruija ; russian: Финнмарк) was a county in the northern part of Norway, and it is scheduled to become a county again in 2024.
On 1 January 2020, Finnmark was merged with the neighbouri ...
county in
Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
,
Finnish Lapland
Lapland ( fi, Lappi ; se, Lappi; smn, Laapi; sv, Lappland; la, Lapponia, links=no) is the largest and northernmost region of Finland. The 21 municipalities in the region cooperate in a Regional Council. Lapland borders the region of North O ...
,
Swedish Lapland
Lapland, also known by its Swedish name Lappland (, fi, Lappi, la, Lapponia), is a province in northernmost Sweden. It borders Jämtland, Ångermanland, Västerbotten, Norrbotten, Norway and Finland. Nearly a quarter of Sweden's land area ...
,
Svalbard
Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
. It was unexpectedly not found in the similar climate of
Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
Altai Mountains
The Altai Mountains (), also spelled Altay Mountains, are a mountain range in Central Asia, Central and East Asia, where Russia, China, Mongolia and Kazakhstan converge, and where the rivers Irtysh and Ob River, Ob have their headwaters. The m ...
in central Siberia, and possibly the
Xinjiang
Xinjiang, SASM/GNC: ''Xinjang''; zh, c=, p=Xīnjiāng; formerly romanized as Sinkiang (, ), officially the Xinjiang Uygur Autonomous Region (XUAR), is an autonomous region of the People's Republic of China (PRC), located in the northwest ...
Province of China. Not found in any temperate region which also receives snowfall, except Japan.
Laboratory culture
Lab culture must simulate the freezing cycle of the natural range. Can grow on relatively low water
sucrose
Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula .
For human consumption, sucrose is extracted and refined ...
,
KCl
Potassium chloride (KCl, or potassium salt) is a metal halide Salt (chemistry), salt composed of potassium and chlorine. It is odorless and has a white or colorless vitreous lustre, vitreous crystal appearance. The solid dissolves readily in wa ...
, and -mannitol. Higher mycelial growth and lower optimal mycelial growth temp (to ) if increased intracellular osmosis. Able to utilize nutrients from partially thawed low-water PDA. Vegetative
hypha
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 ...
e do not accumulate sclerotinial proteins when cultured at but do at , and mycelial proteins cultured at are decreased by switch to incubation at . These may be the/one of the reasons for irregular growth, progressing to lethality, at these higher temperatures.