Oceanitis abyssalis: A new species of deep-sea wood-digesting Fungus from the Northwest Pacific abyssal plain.

The abyssal seafloor is an extreme environment, where organisms have to cope with high pressures, low oxygen and nutrient levels, permanent darkness, and low temperatures (with islands of extremely high temperatures around hydrothermal vents). Despite these obstacles, these deep-sea environments are home to a surprising range of organisms, including a number of Fungi which specialize in the decomposition of wood, a material of terrestrial origin. Do date only six species of obligate deepsea Fungi (i.e. Fungi found only in deep-sea environments) have been described, Alisea longicolla, Allescheriella bathygena, Bathyascus vermisporus, Oceanitis scuticella, Periconia abyssa, and Abyssomyces hydrozoicus, of which all except Abyssomyces hydrozoicus are wood-digesting species.

In a paper published in the journal Phytotaxa on 27 August 2024, Yukiro Nagano of the Marine Biodiversity and Environmental Assessment Research Center of the Japan Agency for Marine-Earth Science and Technology, and the Advanced Institute for Marine Ecosystem Change, Mohamed Adbul-Wahab of the Department of Botany and Microbiology at Sohag University, Ryota Nakajima, also of the Marine Biodiversity and Environmental Assessment Research Center of the Japan Agency for Marine-Earth Science and Technology, and Akinori Yabuki, also of the Advanced Institute for Marine Ecosystem Change, describe a new species of deep-sea wood-digesting Fungus from the Northwest Pacific abyssal plain.

The new species is placed in the genus Oceanitis on the basis of a genetic analysis, and given the specific name abyssalis in reference to the environment in which it was found, the abyssal plain of the Northwest  Pacific close to the Kuroshio Extension current boundary. The species is described on the basis of a colony found growing on a branch of wood with bark still attached, from a depth of 5707 m.

Oceanitis abyssalis (TNS-F-70722, holotype): Ascomata on wood. Nagano et al. (2024).

Oceanitis abyssalis produces fleshy yellowish or brownish ascomycota (spore-producing bodies) on the surface of the wood, which are yellowish in colour, 1.2-1.6 mm high and 0.98-1.2 mm in diameter. It is very similar, both morphologically and genetically, to samples of Oceanitis scuticella collected from the Kuril-Kamchatka Trench, but is morphologically different from the original description of Oceanitis scuticella, which was based upon material from bathyal depths near the islands of Vanuatu, which was not genetically analysed, and is no longer available (to date, no deep-sea Fungus has been cultured in the lab). For this reason, Nagano et al. question whether the Kuril-Kamchatka Trench Oceanitis scuticella material should be placed in this species, suggesting that Oceanitis cf abyssalis might be a better designation for the time being.  

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Talaromyces sedimenticola: A new species of Ascomycote Fungus from the deepest part of the Mariana Trench.

The Challenger Deep forms the deepest part of the Mariana Trench, reaching 10 971 m below sealevel. Curiously, recent studies have shown that the hadal depths of the oceans (areas more than 6 km deep) have a higher microbial carbon turnover than occurs at abyssal depths, between 4 km and 6 km below the surface. This has been supported by metagenomic studies which have shown significantly more genes coding for carbohydrate-active enzymes and peptidase are being expressed at these depths. This has led microbiologists to take an interest in the organisms living in the sediments of the deepest ocean trenches. 

In a paper published in the journal Antonie van Leeuwenhoek on 28 February 2024, Hongbo Zhou of the School of Minerals Processing and Bioengineering and the Key Laboratory of Biometallurgy at Central South University, Liting Xu and Wenxian Liu, also of the School of Minerals Processing and Bioengineering at Central South University, Kaiwen Ta of the Institute of Deep-Sea Science and Engineering of the Chinese Academy of Sciences, Xincun Wang of the State Key Laboratory of Mycology at the Institute of Microbiology of the Chinese Academy of Sciences, Jianwei Guo of the College of Agronomy and Life Sciences at Kunming University, Wenxi Luo, Zhiyuan Peng, and Qiaoni Huang, again of the School of Minerals Processing and Bioengineering at Central South University, and Yuguang Wang, once again of the School of Minerals Processing and Bioengineering and the Key Laboratory of Biometallurgy at Central South University, describe a new species of Ascomycote Fungi from the Challenger Deep.

The new species is described on the basis of two strains isolated from samples collected by the Research Vessel Tan Suo Yi Hao in September 2019, from a depth of 10 063 m below sealevel. A genetic analysis of these strains suggests that they belong to the same species, and, surprisingly, that that species  is a member of the genus Talaromyces, which mostly comprises terrestrial moulds, forming a sister taxon to a clade which includes Talaromyces trachyspermus, which is a serious commercial pest species, frequently infecting packaged fruit juices, and Talaromyces assiutensis, which is found growing within the leaves of Mangroves around the South China Sea. The new species is named Talaromyces sedimenticola, in reference to the environment where it was found.

Morphological characteristics of Talaromyces sedimenticola, (k), (l) conidiophores, (m) conidia. Zhou et al. (2024).

While morphologically similar, and genetically close, to other members of the genus Talaromyces, Talaromyces sedimenticola shows some remarkable physiological traits, which mark it out as distinctive. It could be grown at temperatures of between 4°C and 50°C, unlike most Talaromyces species, which typically grow between about 28°C and 40°C. It could also survive and grow over a far wider pH range than any other species within the genus, pH 1.5-12, whereas other Talaromyces species could only survive in the pH range 4-8, with the exception of Talaromyces aculeatus, a widespread soil-dwelling form, which can survive over the range pH 1-7. Talaromyces sedimenticola is also remarkably halotollerant, able to flourish on media with 0-14% sodium chloride (weight over volume). More curiously, Talaromyces sedimenticola was unable to metabolise sucrose, tryptone, or monobasic potassium phosphate, all of which can be utilised by other members of the genus, although it was able to utilise other common foodstuffs, such as glucose, maltose, lactose, xylose, soluble starch, glycerol, peptone, ammonium sulphate, potassium phosphate, potassium chloride, and magnesium sulphate. 

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Tuber itzcuinzapotl: A new species of edible Truffle from Mexico.

Truffles, Tuber spp., are Ascomycote Fungi which from ectomycorrhizal relationships with a range of forest Plants, including Pines, Oaks, Hickories, and Orchids. They are distinguished for their large, tuber-like ascomata (fruiting bodies), which are formed underground, which often have highly distinctive aromas and flavours, leading to some species being traded as high-value gourmet items.

There are currently 25 species of Truffle known from Mexico, mostly from the temperate forests of the north and the mountains of the Neovolcanic axis. However, none of these are currently traded as foodstuffs, despite Mexico a globally leading countries in terms of the number of edible wild Fungi consumed, with about 500 species, making it second only China, where about 1000 are consumed. However, recent efforts have found that the non-native Black Truffle, Tuber melanosporum, will form ectomycorrhizal relationships with native Mexican Oaks, and several species found in Mexico are considered to have potential for commercial development, including the Pecan Truffle, Tuber lyonii, which is commercially exploited in the US and Canada, and can trade for up to US$400 per kg.

In a paper published in the journal Phytotaxa on 26 January 2024, Javier Isaac de la Fuente of the Colegio de Postgraduados at Campus Montecillo, Wendy Rosales-Rosales of the Instituto Tecnológico Superior de Zongolica of the Tecnológico Nacional de México, César Romero Martínez-González of the Instituto Tecnológico de Ciudad Victoria of the Tecnológico Nacional de México, Magdelana Martínez-Reyes, also of the Colegio de Postgraduados at Campus Montecillo, Andrea Carolina Elizondo-Salas, also of the Instituto Tecnológico Superior de Zongolica of the Tecnológico Nacional de México, and Jesús Pérez-Moreno, agian of the Colegio de Postgraduados at Campus Montecillo, describe a new species of edible Truffle from the Coniferous mixed forests of eastern Mexico.

The new species is named Tuber itzcuinzapotl, where 'itzcuinzapotl' means 'Dog's Zapote' in the Nahua language (a Zapote is a type of fruit). This Truffle produces subglobose fruiting bodies with a light brown, verrucous-granular outer surface, and an gray or pale brown interior, reaching up to 28 mm by 28 mm in size, with a distinctive fruity taste and smell. It is found growing in association with Mexcan Weeping Pines, Pinus patula, in Veracruz State, Mexico.

Tuber itzcuinzapotl (Holotype). Fresh ascomata fruiting body. De la Fuente et al. (2024).

Mexico has a significant culture of wild Fungus consumption, with over 500 types of Fungi consumed by members of all ethnic groups, and in particular rural communities living close to woodland. However, almost all consumed Fungi are epigeal, i.e, found above the ground, such as Mushrooms, with very little exploitation of subterranean species occurring. This is surprising, as Mexico is one of the most biodiverse regions in the world for Oaks, and Oaks are particularly associated with Fungi producing underground fruiting bodies. 

Tuber itzcuinzapotl is known to be consumed by members of the Nahua ethnic group living in the Sierra de Zongolica region of Veracruz State, Mexico, where it is referred to as 'itzcuinzapotl' (the specific name chosen for the species). Local folklore has it that people began to consume these Fungi after observing Dogs digging them up and eating them. Knowledge of the Fungus appeared to be restricted to older women in the community. Such local knowledge of wild foodstuffs is considered to be at risk in the region as traditional cultures are eroded, leading to loss of knowledge and a reduction and homogenisation in the number of foodstuffs consumed by Humans both in Mexico and globaly.

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Fungal Meningitis infections reported at two Mexican hospitals.

On 11 May 2023, the United States of America Centers for Disease Control and Prevention notified the Mexico General Directorate of Epidemiology of five cases with central nervous system infection in the United States of America, according to a press release issued by the World Health Organization on 1 June 2023.. All five cases were females with a history of undergoing surgical procedures performed under spinal anaesthesia in Mexico. The surgeries were performed in two private clinics, located in the city of Matamoros in Tamaulipas State, on the border with the USA.  Laboratory test results from samples collected from patients in the USA and Mexico were consistent with Meningitis caused by pathogenic Fungi. Fungal Meningitis is rare but can be fatal and requires immediate medical care. 

As of 26 May 2023, the health authorities from Mexico and the USA have reported a total of 20 cases presenting with signs and symptoms compatible with central nervous system infection, including two deaths reported by the United States of America Centers for Disease Control and Prevention. Patients presented to the hospital with symptoms including headache, fever, nausea, vomiting, sensitivity to light, and fainting after receiving surgical procedures in two private clinics in Mexico, between January and April 2023.

The Mexico Epidemiological Diagnosis and Reference Institute has received five samples of cerebrospinal fluid that tested positive for a Fungus, Fusarium solani by real-time polymerase chain reaction. Additionally, according to the health authorities from the USA, the laboratory results from nine suspected cases were consistent with Meningitis, of which two cerebrospinal fluid and two blood samples showed elevated levels of (1,3)-beta-D-glucan, a biomarker for Fungal infection.  Two pan-fungal polymerase chain reaction tests were negative.

Fusarium solani is a common, filamentous Acomycote Fungi, found in soil systems worldwide, but known to occasionally cause opportunistic infections, typically of the eyes. Although distinct from other members of the genus Fusarium, Fusarium solani is now recognised to be a species complex, i.e. a group of closely related and morphologically similar species, which are nonetheless genetically isolated from each other. 

Hyphae of Fusarium solani stained with Prussian blue. Josef Reischig/Wikimedia Commons.

According to the investigation performed, a total of 547 people had these procedures  between January and April 2023 in the concerned two private clinics, of whom 304 (56%) reside in Mexico, 237 (43%) in the United States, and one in Canada.

Several species of Bacteria, Viruses, Fungi, and Parasites can cause Meningitis, an inflammation of the tissues surrounding the brain and spinal cord. Fungal Meningitis can develop after a Fungal infection spread from somewhere else in the body to the central nervous system. It can be fatal and requires immediate medical care.  While rare, medical and surgical procedures can lead to Fungal Meningitis if medical devices or medications are contaminated with Fungi, or if proper infection prevention control practices are not taken. This type of healthcare-associated infection can lead to severe illness or death. Healthcare-associated Fungal Meningitis outbreaks have occurred among patients who received spinal anesthesia.

Fungal Meningitis cases following a medical/surgical procedure are very infrequent and unusual. In 2012, the United States of America Centers for Disease Control and Prevention investigated a multistate outbreak of Fungal Meningitis and other infections among patients who received contaminated preservative-free methylprednisolone acetate steroid injections; 753 cases were reported, including 64 deaths in 20 States in the USA.

The source, vehicle, and the transmission route for the current outbreak remains unknown, although the investigations are ongoing. A Fungal infection is suspected based on preliminary information provided by the health authorities from Mexico and the USA.

Each year, more than a million people from the USA participate in medical tourism. In 2017, more than 1.4 million Americans sought health care in a variety of countries around the world. These medical tourists commonly travel to Mexico, Canada, and countries in Central America, South America, and the Caribbean. At present, there is no evidence to suggest any secondary spread from these cases of health care associated Fungal Meningitis The involved healthcare facilities where the procedures were undertaken have been closed since 13 May. However, there is an ongoing investigation and follow up of people who may have been exposed to Fungal infections. This may lead to additional cases being reported until the follow up of people exposed to such procedure is completed.

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Drechslerella daliensis & Drechslerella xiaguanensis: Two new species of predatory Fungi from Yunnan Province, China.

Predatory Fungi are important controls on Nematode populations in many soil ecosystems. The majority of these Fungi belong to the Ascomycote Family Orbiliaceae, which currently includes 116 predatory species, divided into three genera. Arthrobotrys, which contains 67 species, and which traps Nematodes in a network of sticky hyphae, Dactylellina, which contains 34 species and which captures Nematodes with sticky knobs, and Drechslelrella, which contains 15 species, and which produces constricting rings, used to trap Nematodes in a lasso-like action.

The genus Drechslelrella was first described by the Indian mycologist Chirayathumadom Venkatachalier Subramanian in 1963, and has been found in a wide variety of ecosystems, including forest soils, Mangrove sediments, freshwater sediments, brackish water sediments, heavy metal polluted areas and even in tree trunks and animal faeces. They are typically found in the upper part of the soil or overlying humus layer, where the density of Nematodes appears to be highest. The constricting rings produced by these Fungi are made up of three cells, which swell rapidly when a Nematode is detected. 

In a paper published in the Biodiversity Data Journal on 16 December 2022, Fa Zhang of the Institute of Eastern-Himalaya Biodiversity Research at Dali University, and the Center of Excellence in Fungal Research and School of Science at Mae Fah Luang University, Saranyaphat Boonmee, also of the Center of Excellence in Fungal Research and School of Science at Mae Fah Luang University, Jutamart Monkai, again of the Center of Excellence in Fungal Research at Mae Fah Luang University, and Xiao-Yan Yang and Wen Xiao, also of the Institute of Eastern-Himalaya Biodiversity Research, and of the Key Laboratory of Yunnan State Education Department on Er’hai Lake Basin Protection and the Sustainable Development Research, at Dali University, describe two new species of Drechslerella from fire-disturbed forest soil from the slopes of Cangshan Mountain, to the west of Dali city in Yunnan Province, China.

The new Fungi were cultivated from soil samples spread on agar, and prompted to produce traps by the introduction of the free-living Nematode Panagrellus redivivus as bait. They were confirmed as new species by the extraction of DNA, and comparison to other species on the GenBank database, using the BLASTn online tool. The phylogenetic relationships of the new species were established using the MrBayes software package.

The first new species is named Drechslerella daliensis, where 'daliensis' means 'from Dali', in reference to the city. This Fungus formed white, cottony colonies on the cultivation medium, reaching a diameter of 50 mm after 18 days. Two types of conidia (spore producing bodies) were produced, both on conidiophores (conidia-bearing hyphae) 125-335 µm in length. The macroconidia were roughly 20-49.5 µm long and 8.5-15 µm wide, smooth, ellipsoid, broadly rounded at the apex and truncated at the base. The microconidia were 6.5-22 µm long and 3.5-7 µm wide, smooth, clavate or bottle-shaped, broadly rounded at the apex and truncated at the base. Drechslerella daliensis was observed to trap Nematodes with constricting rings on stalks 5.5–11 µm long, with an outer diameter of 21–32 µm and an inner diameter of 2–21 µm.

Drechslerella daliensis (holotype, CGMCC3.20131). (a) Culture colony; (b), (c) Macroconidia; (d) Microconidia; (e) Constricting rings; (f), (g) Conidiophores. Scale bars: (a) 1 cm; (b)–(g) 10 µm. Zhang et al, (2022).

The second species is named Drechslerella xiaguanensis, where 'xiaguanensis' means 'from Xiaguan' in reference to the district where the soil samples were collected. This Fungus also formed white, cottony colonies on the growth medium, reaching 50 mm in diameter after 15 days. The conidia of this species were born on conidiophores 145-315 µm in length, with a single type of conidia being produced, these being 33-52 µm in length and 9.5–28 µm in width. Constricting rings were born on stalks 5–11.5 µm long, and had an outer diameter of 19–27.5 µm and an inner diameter of 12.5–20.5 µm.

Drechslerella xiaguanensis (holotype, CGMCC3.20132). (a) Culture colony; (b), (c) Conidia; (d) Germinating conidia; (e) Constricting rings; (f), (g) Conidiophore. Scale bars: (a) 1 cm; (b)–(g) 10 µm. Zhang et al. (2022).

The phylogenetic analysis confirmed that both species could be placed within the genus Drechslerella, with Drechslerella daliensis being recovered as the sister species to Drechslerella hainanensis, known from Hainan, an island province of China in the South China Sea, and Drechslerella xiaguanensis as the sister species to Drechslerella bembicodes, a species from New Zealand.

Maximum Likelihood tree, based on combined ITS, TEF1-α and RPB2 sequence data from 42 Nematode-trapping taxa in Orbiliaceae. Bootstrap support values for Maximum Parsimony (red) and Maximum Likelihood (black) equal or greater than 50% and Bayesian posterior probabilities values (green) greater than 0.90 are indicated above the nodes. New isolates are in blue, ex-type strains are in bold. Zhang et al. (2022).

Zhang et al. note the the network of sticky hyphae used by the genus Arthrobotrys appears to be a more efficient trap than the methods used by Drechslerella or Dactylellina, and that, under normal circumstances, this genus is the most abundant in the upper soil layer, where Nematodes are most abundant. However, in the fire-damaged forest soils, the reverse appeared to be the case, with Arthrobotrys almost absent, while Drechslerella and Dactylellina are abundant. They theorise that in this environment, Arthrobotrys has been killed off by the burning of the upper soil layer, allowing the other two genera to invade rapidly from colonies in deeper soil layers.

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Menisporopsis aquatica: A new species of freshwater Fungus from Zhejiang Province, China.

Although generally thought of as terrestrial organisms, Fungi are an integral part of marine, freshwater, and wet terrestrial ecosystems, helping to break down dead organic tissue, and in particular wood. The genus Menisporopsis contains 13 species of marine and freshwater Ascomycote Fungi producing pigmented, synnematous conidiophores (cylindrical asexual spores). The genus was first described in 1952 to describe a Fungus found growing on rotting Cocoa leaves in Ghana.

In a paper published in the Biodiversity Data Journal on 21 October 2022, Jia-Hao Chen of Jiangxi Agricultural University, Dian-Ming Hu, also of Jiangxi Agricultural University, and of the Jiangxi Environmental Engineering Vocational College, and Hai-Yan Song, Zhi-Jun Zhai, Lin La, and Kang-Hui Lin, also of Jiangxi Agricultural University, describe a new species of Menisporopsis found growing on submerged wood in a brook in Zhejiang Province, China.

The new species was established as such using a molecular phylogeny based upon  a combined two-loci dataset, including the internal transcribed spacer sequences and the nuclear ribosomal large subunit gene sequences. This found the new species to be nested within the Menisporopsis clade, forming a sister group to the branch comprising Menisporopsis breviseta and Menisporopsis pandanicola, with Menisporopsis dushanensis forming the sister group to all three of these species. Having been established as a new species, the Fungus was named Menisporopsis aquatica in reference to its freshwater habitat.

Phylogenetic tree obtained from the DNA sequence data of internal transcribed spacer sequences and ribosomal large subunit sequences of 32 strains showing taxa in Menisporopsis and Dictyochaeta. The new isolates are shown in bold, red. The bootstrap values (greater than 75%) and Bayesian posterior probabilities (greater than 95%) are presented at the nodes. The scale bar shows the number of estimated mutations per site. The tree was rooted to Leptosporella arengae (MFLUCC 15-0330) and Leptosporella bambusae (MFLUCC 12-0846). Chen et al. (2022).

Menisporopsis aquatica was found growing on submerged wood in the Qianjia Lou Brook near the town of Daoxu in Shangyu District. The Fungus forms a pale yellow to pale brown branching mycelium. It produces black setae, which are surrounded by tightly packed brown conidiophores. 

Menisporopsis aquatica (HFJAU 10038, Holotype) (a)-(b) conidiophores and conidia on submerged wood; (c) conidiophores with seta; (d) apex of the conidiophore with developing conidia; (e) base of the conidiophore; (f) seta; (g)-(j) conidia; (k) colony on Potato dextrose agar. Scale bars: (a)-(b), 100 µm; (c), 50 µm; (d)-(j), 10 µm. Chen et al. (2022).

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