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. 

See also...

Fossil Thrips from the Early Eocene of France.

Thrips (the term is both singular and plural) are tiny (usually less than 1 mm) Insects related to Lice and True Bugs. They have wings, but are poor flyers, and feed by sucking fluids from plant or animal hosts. Thrips do not undergo metamorphosis, the young are essentially smaller, non-reproducing versions of the adults. Due to their small size and ubiquitous nature, it is probable that Thrips are one of the larger Insect groups, though they are relatively understudied, with little work carried out on Thrips that do not have agricultural significance.

In a paper published in the journal Acta Palaeontologica Polonica on 19 December 2011, Patricia Nel of the Muséum national d'Histoire naturelle in Paris and AgroParisTech, Alexander Schmidt of the Courant Research Centre Geobiology at Georg−August−Universität Göttingen, Claus Bässler of the Nationalparkverwaltung Bayerischer Wald and André Nel, also of the Muséum national d'Histoire naturelle describe a new species of Thrips from Oise Amber, which originates from the early Eocene of the Paris Basin (about 53 million years old, close to the Paleocene–Eocene Thermal Maximum).

The new species is placed in the genus Uzelothrips, and given the species name eocenicus, meaning from the Eocene. The genus Uzelothrips has to date contained only a single species, the extant Uzelothrips scabrosus, which has been recorded from Brazil, Singapore, Australia and Angola. Uzelothrips eocenicus is almost identical to the modern species, differing only in the antennae, on which segments III and IV are fused in the modern species but separate in the Eocene one. The species is described from two specimens, one female and one of uncertain sex.

Macropterous specimen of Uzelothripid Insect Uzelothrips eocenicus, Lowermost Eocene, Le Quesnoy, Oise, France. (A) Dorsal view; inset: detail of antennal segments III and IV. (B) Drawings of right antennal segments III and IV in dorsal (B1) and ventral (B2) views. (C) Camera lucida drawing of in dorsal view. Nel et al. (2011).

Nel et al. also found a number of fungal fragments attached to one of the specimens. These are thought to be from a Sooty Mould, a type of fungus that primarily gains nutrients from the excreta of Aphids, Scale Insects etc. These have not previously been documented from Thrips, but examination of photographic records of Uzelothrips scabrosus showed that several specimens were in fact carrying similar Fungi.

Ascomycetes found attached to the cuticle of the fossil and extant Uzelothripid Insects. The small panels show higher magnification images of some fossil and extant fungi found at the locations indicated by the arrows. (A) Fossil apterous specimen of Uzelothrips eocenicus. The image is composed of photographs obtained from those optical sections which show the attached fungi most clearly. The arrowhead in the uppermost left panel indicates a Capnosporium−like conidium; the arrowhead in the middle right panel indicates a tapering hypha tip with dividing stage. (B) Recent specimen of Uzelothrips scabrosus. The asterisk refers to the elongated hypha that has possibly grown on the surface of the thrips after attachment. Nel et al. (2011).

See also...

 Three new species of Thrips from Japan, Malaysia and Australia.

 Four new species of Thrips from China, Taiwan, Indonesia, Papua New Guinea and Australia.

 A new species of Thrips from Chiapas State, Mexico.

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