Ulocladium botrytis
The genus "Ulocladium" was first discovered in 1851 by German mycologist, Preuss, in a small batch of his specimens. An abundant hyphomycetous growth of "Ulocladium" was found on a thin sliver of wood and was drawn and labeled by Preuss as "Ulocladium botrytis" in his manuscript. This sample was later acquired by the Botanisches Museum in Berlin. At the time, the name of the genus and the species type was published as a nomen nudum due to insufficient description. Furthermore, certain taxa of "Ulocladium" greatly resemble "Alternaria" species, resulting in occasional misidentifications. During the late 1900s, a mycologist named Curran described "Alternaria maritima" as a species new to Ireland. However, Curran's new claim was questioned when another mycologist, Kohlmeyer, initiated a movement to verify the classification of this fungus. After much study, it was found that "Alternaria maritima" was in fact "Ulocladium botrytis". Although "Ulocladium" is now a genus of its own, it was once included in the genus "Alternaria". Several recent DNA-based phylogenetic studies have presented convincing data which places "Ulocladium" species within the genus "Alternaria"; however, "Ulocladium" species do not produce certain compounds and metabolites produced by "Alternaria" species. Some modern sources believe that "Ulocladium botrytis" should be considered conspecific with "Ulocladium atrum". "Ulocladium botrytis" is a hyphomycetous mould that favors growth in damp indoor environments. Although it mainly uses nitrogen, other nutrient sources have been tested to determine that "U. botrytis" growth rate is dependent on the type of media provided. "Ulocladium botrytis" colonies are commonly velvety in texture and grow in an assortment of colors ranging from dark blackish brown to black. The hyphae are 3-4 µm in diameter and yellow to golden brown in colour with a smooth or slightly rough texture. Conidiophores are short and either erect and ascending, or contorted into various shapes. In addition, they are often bifurcated near the apex at sharp angles. "Ulocladium botrytis" conidiophores are typically light golden brown in color and smooth, with a length of up to 100 µm and a thickness of around 3-5 µm. The conidia themselves are typically ellipsoidal or obovoid in shape; spheroidal conidia are uncommon in this species. They are golden brown in color and frequently have a minute hilum and a warty, verrucose exterior ornamentation. "Ulocladium botrytis" conidia typically have three transverse septa and longitudinal septum, but these septa rarely overlap to form a cross. This species never forms conidial chains and the conidia never have a beak. "Ulocladium botrytis" is an anamorphic fungus, thus it undergoes asexual reproduction. Although it is an asexual fungus, "U. botrytis" possesses the mating type locus, which consists of two dissimilar DNA sequences termed MAT1-1-1 and MAT1-2-1. These "U. botrytis" MAT genes are essential for controlling colony size and asexual traits such as conidial size and number in "U.botrytis". The "U. botrytis" MAT genes have lost the ability to regulate sexual reproduction in "U. botrytis"; however, they have the ability to partially induce sexual reproduction in "Cochliobolus heterostrophus", a heterothallic species, upon heterologous complementation. "Ulocladium botrytis" has cellulolytic ability and contains a cellulose-degrading enzyme complex that can degrade recalcitrant plant litter under alkaline conditions, a trait that is uncommon in other cellulolytic systems. This fungus' ability to hydrolyze cellulose in the solid form is best at a pH of 6.0, as this pH allows maximal growth of "U. botrytis" under alkaline conditions. In contrast, its ability to hydrolyze liquid cellulose under alkaline conditions is best at a pH of 8.0. Additionally, a new tyrosine kinase (p56tck) inhibitor called ulocladol, with the molecular formula C16H14O7, was found in ethyl acetate extract from "U. botrytis". "Ulocladium botrytis" also synthesizes extracellular keratinases and can grow in the presence of keratin. Moreover, this fungus can produce carboxymethyl cellulase and protease on "Eichhornia crassipes" wastes. As a fungus, "Ulocladium botrytis" produces a diverse collection of chemical compounds and metabolites. It produces mixtures of volatile organic compounds that include terpenes, alcohols, ketones, and nitrogen-containing compounds. Furthermore, "U. botrytis" aids in decreasing aldehyde levels. Dodecane and 9,10,12,13-tetrahydroxyheneicosanoic acid were also found as metabolites of "U. botrytis". Another "U. botrytis" metabolite is 1-hydroxy-6-methyl-8-(hydroxymethyl)xanthone, which has antimicrobial effects indicating its identification as an antifungal metabolite. Importantly, a major protein allergen of "Alternaria alternata", termed Alt a 1, and an allergen homologous to it is expressed in the excretory-secretory materials of "U. botrytis". The distribution of "Ulocladium botrytis" is fairly broad, wherein it has been found worldwide in areas of Europe, North America, Egypt, India, Pakistan, and Kuwait. It is often isolated from soil, where it is a common contaminant; however, "U. botrytis" also grows on rotten wood, paper, and other textiles or on dead herbaceous plants. It also heavily favors growth in damp indoor environments. This fungus has been found growing on deciduous alder trees ("Alnus") which belong to the birch family Betulaceae. Trees in this family include the American green alder and the mountain alder. "U. botrytis" can also be found growing on the evergreen coniferous tree genus "Pseudotsuga" of the family Pinaceae; different trees include the Douglas fir and the big-cone spruce. In addition, this fungus can grow on the flowering plant genus "Sphaeralcea" of the mallow family Malvaceae; plants include the desert hollyhock and the prairie mallow. A previously conducted study also isolated a unique strain of "Ulocladium botrytis", strain number 193A4, from the marine sponge "Callyspongia vaginalis". Another independent study found seed-borne "Ulocladium botrytis " from pearl millet ("Pennisetum typhoides"). Relationships with other organisms coexisting in the same ecosystem has served to be beneficial for some organisms and this applies to "U. botrytis". "Ulocladium botrytis" is capable of surviving in xerophilic ecosystems and alkaline-calcareous soils, both extreme habitats, when associating with the tree species "Scutia buxifolia". The "U. botrytis" strain associated with this environment is called LPSC 813 and has great cellulolytic ability. "Ulocladium. botrytis" has potential, albeit limited, to be used as a biocontrol agent against the parasitic herbaceous plant genus "Orobanche" that affect the yield of certain crops like tomatoes. "Ulocladium botrytis" is also capable of "in vitro" antagonism of root-disease pathogens such as "Heterobasidion annosum", "Phellinus weirii", and "Armillaria ostoyae". Apart from "U. botrytis", other "Ulocladium" species such as "U. atrum" and "U. oudemansii" also present biocontrol potential. "Ulocladium botrytis" is currently regarded as a source of home allergen sensitization and is used in skin-prick tests that test for mould allergens and work-related allergens. This is due to the production and detection of Alt a 1, the major allergen produced by "Alternaria alternata", in "U.botrytis". In addition, "U. botrytis" also releases another allergen, homologous to Alt a 1, that possesses the capacity to cause allergic responses in humans. The allergic symptoms caused by "U. botrytis" are compatible with rhinitis and asthma; however, "U. botrytis" was also found in patients of allergic fungal sinusitis. Importantly, "Ulocladium botrytis" is rarely pathogenic to humans but has been found to be associated with cases of onychomycosis, a fungal infection of the nail.
Growth and morphology
Commonly found in soil and damp indoor environments, "U.botrytis" is a hyphomycetous mould found in many regions of the world.