ISOLATION OF PSYCHROTOLERANT, PSYCHROPHILIC AND XEROPHILIC FUNGI OF SOIL SAMPLES FROM AMAZON

ANA BEATRIZ NASCIMENTO DA SILVA; Érica Simplício de Souza; Pragya Sharma; John E Hallsworth; João Vicente Braga de Souza

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Submission

Paper Title

ISOLATION OF PSYCHROTOLERANT, PSYCHROPHILIC AND XEROPHILIC FUNGI OF SOIL SAMPLES FROM AMAZON

Authors

ANA BEATRIZ NASCIMENTO DA SILVA
Érica Simplício de Souza
Pragya Sharma
John E Hallsworth
João Vicente Braga de Souza

Modality

Abstract

Subject area

Stress in populations, fungal communities, and symbiotic interactions

Publishing Date

15/05/2019

Country of Publishing

Brasil

Language of Publishing

Inglês

Paper Page

https://www.even3.com.br/anais/isfus/161721-isolation-of-psychrotolerant-psychrophilic-and-xerophilic-fungi-of-soil-samples-from-amazon

ISBN

978-85-5722-210-6

Keywords

Amazonian soils; Microbial ecology, Psychrophiles; Saprotrophic fungi, Xerophiles, Water activity

Summary

Psychrophilic microbes are abundant in cold environments, and xerophilic species are commonplace in low water-activity habitats. Here, we consider whether psychrophilic and xerophilic fungi might also occur in soils of the hot, humid Amazonian rainforest. The soil samples were collected from primary rainforest belonging to the grounds of the Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus-AM-Brazil (03°05' 38.29" S; 59° 59' 16.92" W) in March 2019. Soil samples were collected from a depth of 100 cm (clay-dominated subsoil) and from the surface (humus-rich topsoil), serially diluted in water, and used to inoculate nutrient media. For psychrotolerant and psychrophilic fungi, inoculations were carried out on potato dextrose agar supplemented with chloramphenicol (100 mg/L); incubations were then carried out at 5, 10, 15 and 25°C. For xerophilic fungi, inoculations were carried out on potato dextrose agar supplemented with chloramphenicol (100 mg/L) either without glycerol (0.998 water activity) or with glycerol at 3, 4.5 or 6 M (0.872, 0.811 and 0.745 water activity); and then incubated at 25°C. Petri plates were inspected daily for 14-day to check for fungal isolates. The number of colony-forming units (CFU) per gram were determined. From surface soil samples, one isolate was obtained at 5oC (33 CFU/g), 11 morphologically distinct isolates at 10oC (1x103 CFU/g), 18 morphologically distinct at 15oC (2x104 CFU/g), and 20 morphologically distinct at 25oC (5x104 CFU/g). From the 100-cm-deep soil samples, no isolates were obtained at 5oC, two morphologically distinct isolates at 10oC (5x102 CFU/g), eight morphologically distinct isolates at 15oC (2x103 CFU/g), and 10 morphologically distinct isolates at 25oC (1x104 CFU/g). From surface soil samples, no isolates were obtained at 6 M glycerol, seven morphologically distinct isolates at 4.5 M glycerol (300 CFU/g), 10 morphologically distinct isolates at 3 M glycerol (1x104 CFU/g), and 20 morphologically distinct isolates on media without glycerol (5x104 CFU/g). From the 100-cm-deep soil samples, no isolates were obtained at 6 M glycerol, two morphologically distinct isolates at 4.5 M glycerol (133 CFU/g), three morphologically distinct isolates at 3 M glycerol (200 CFU/g), and 10 morphologically distinct isolates on media without glycerol (1x104 CFU/g). These plates are still being incubated, so it is unclear as yet whether isolates will ultimately grow on the most-stressful xerophile (6 M glycerol) medium. Nevertheless, xerophiles are defined as those isolates able to grow at =0.850 (Pitt, 1975), so those already growing at 4.5 M glycerol are true xerophiles. Studies are now underway on the growth kinetics of these isolates to establish the extent of their psychro- and xerotolerance. Paradoxically, in these Amazonian soils that do not experience temperatures below 20ºC and are not known to dry out, psychrotolerant/philic and xerotolerant/philic fungi are present. As might be expected, however, these are more abundant in the biodiverse and saprotroph-rich surface soil. Acknowledgments: We sincerely thank the Fundação de Amparo a Pesquisa do Estado do Amazonas for undergraduate fellowship

Title of the Event: III International Symposium on Fungal Stress – ISFUS
City of the Event: São José dos Campos
Title of the Proceedings of the event: Annals of the International Symposium on Fungal Stress – ISFUS
Name of the Publisher: Even3
Means of Dissemination: Meio Digital

How to cite

SILVA, ANA BEATRIZ NASCIMENTO DA et al.. ISOLATION OF PSYCHROTOLERANT, PSYCHROPHILIC AND XEROPHILIC FUNGI OF SOIL SAMPLES FROM AMAZON.. In: Annals of the International Symposium on Fungal Stress – ISFUS. Anais...São José dos Campos(SP) Hotel Nacional Inn, 2019. Available in: https//www.even3.com.br/anais/ISFUS/161721-ISOLATION-OF-PSYCHROTOLERANT-PSYCHROPHILIC-AND-XEROPHILIC-FUNGI-OF-SOIL-SAMPLES-FROM-AMAZON. Access in: 17/07/2025