Growth study under combined effects of temperature, pH and salinity and transcriptome analysis revealed adaptations of Aspergillus terreus NTOU4989 to the extreme conditions at Kueishan Island Hydrothermal Vent Field, Taiwan

Abstract

A high diversity of fungi was discovered on various substrates collected at the marine shallow-water Kueishan Island Hydrothermal Vent Field, Taiwan, using culture and metabarcoding methods but whether these fungi can grow and play an active role in such an extreme environment is unknown. We investigated the combined effects of different salinity, temperature and pH on growth of ten fungi (in the genera Aspergillus, Penicillium, Fodinomyces, Microascus, Trichoderma, Verticillium) isolated from the sediment and the vent crab Xenograpsus testudinatus. The growth responses of the tested fungi could be referred to three groups: (1) wide pH, salinity and temperature ranges, (2) salinity-dependent and temperature-sensitive, and (3) temperature-tolerant. Aspergillus terreus NTOU4989 was the only fungus which showed growth at 45˚C, pH 3 and 30 ‰ salinity, and might be active near the vents. We also carried out a transcriptome analysis to understand the molecular adaptations of A. terreus NTOU4989 under these extreme conditions. Data revealed that stress-related genes were differentially expressed at high temperature (45˚C); for instance, mannitol biosynthetic genes were up-regulated while glutathione S-transferase and amino acid oxidase genes down-regulated in response to high temperature. On the other hand, hydrogen ion transmembrane transport genes and phenylalanine ammonia lyase were up-regulated while pH-response transcription factor was down-regulated at pH 3, a relative acidic environment. However, genes related to salt tolerance, such as glycerol lipid metabolism and mitogenactivated protein kinase, were up-regulated in both conditions, possibly related to maintaining water homeostasis. The results of this study revealed the genetic evidence of adaptation in A. terreus NTOU4989 to changes of environmental conditions.

Genome sequence analysis of deep sea Aspergillus sydowii BOBA1 and effect of high pressure on biodegradation of spent engine oil

“…It was proposed that in presence of surfactant, the surfactant-compatible BOBA1 may influence the biodegradation of different PAHs to different degrees. High diversity of deep-sea fungi have acclimatized and evolved multitude of mechanisms to grow and play an active role in extreme environment of different pH, salinity, pressure and temperature 29 . The A. sydowii BOBA1 could grow in the pH range of 4.0–10.0, NaCl concentration of 1–10% (w/v) and temperature range of 10–40 °C, demonstrating its capability to grow and catalyze diverse function at broad environmental conditions (Table 2 ).…”

Penicillium and Aspergillus Species Characterization: Adaptation to Environmental Factors and Sensitivity to Aqueous Medicinal Plants Extracts

“…In the same sense, P. digitatum and P. italicum grow optimally at 25°C [2]. Recently, Pang, et al [4] suggested that the optimum mycelial growth temperatures of Aspergillus spp. were ranged from 25 to 30°C.…”

“…possessed a worldwide distribution and over large a range of ecological habitats [1,2]. These two genera are ubiquitous and can be colonize the soil, air, vegetation, insects, nematodes and indoor environments [3,4].…”

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“…and Penicillium spp [4,9,10]. Generally, these fungi may develop with a huge range of optimum temperatures from 20 to 30°C, but it is could be grow in the range 0-40°C under in vitro condition [4,11]. In the same sense, the highest metabolic activities, cellular growth, conidial production and sporulation of Aspergillus spp.…”

“…In indeed, slight environmental factors variations may modify their morphological characters ecological habitats of Aspergillus and Penicillium species, the nutrients availability at different pH levels and temperature degrees in numerous ecological conditions can influence growth, sporulation and activity of Aspergillus spp. and Penicillium spp [4,9,10]. Generally, these fungi may develop with a huge range of optimum temperatures from 20 to 30°C, but it is could be grow in the range 0-40°C under in vitro condition [4,11].…”