Salt Stress Response of Sulfolobus acidocaldarius Involves Complex Trehalose Metabolism Utilizing a Novel Trehalose-6-Phosphate Synthase (TPS)/Trehalose-6-Phosphate Phosphatase (TPP) Pathway

Abstract

The Crenarchaeon Sulfolobus acidocaldarius has been described to synthesize trehalose via the maltooligosyltrehalose synthase (TreY) and maltooligosyltrehalose trehalohydrolase (TreZ) pathway and the trehalose glycosyltransferring synthase (TreT) pathway has been predicted. Deletion mutant analysis of single and double deletion strains of ΔtreY and ΔtreT in S. acidocaldarius revealed that next to these two pathways a third, novel trehalose biosynthesis pathway is operative in vivo: the trehalose-6-phosphate (T6P) synthase/T6P phosphatase (TPS/TPP) pathway. In contrast to known TPS proteins, which belong to the GT20 family, the S. acidocaldarius TPS belongs to the GT4 family establishing a new function within this group of enzymes. This novel GT4-like TPS turned out to be mainly present in the Sulfolobales. The ΔtreY/ΔtreT/Δtps triple mutant of S. acidocaldarius lacking the ability to synthesize trehalose showed no altered phenotype under standard conditions or heat stress, but was unable to grow under salt stress. Accordingly, in the wild type strain a significant increase of intracellular trehalose formation was observed under salt stress. Quantitative real-time PCR showed a salt stress mediated induction of all three trehalose synthesizing pathways. This demonstrates in Archaea that trehalose plays an essential role for growth under high salt conditions. Importance The metabolism and function of trehalose as compatible solute was not well understood in Archaea. This combined genetic and enzymatic approach at the interface of microbiology, physiology and microbial ecology gives important insights into survival under stress, adaptation to extreme environments, and the role of compatible solutes in Archaea. Here we unravelled the complexity of trehalose metabolism and present a comprehensive study on trehalose function in stress response in S. acidocaldarius. This sheds light on the general microbiology and the fascinating metabolic repertoire of Archaea involving many novel biocatalysts such as glycosyltransferases with great potential in biotechnology.

Machine Learning Uncovers a Data-Driven Transcriptional Regulatory Network for the Crenarchaeal Thermoacidophile Sulfolobus acidocaldarius

“…In order to characterize the iModulons, we first built a scaffold TRN ( Supplementary File 2 ) based on the existing literature for S. acidocaldarius , consisting of 346 gene-regulator interactions for 28 regulators ( Koerdt et al, 2011 ; Reimann et al, 2012 ; Lassak et al, 2013 ; Märtens et al, 2013 ; Orell et al, 2013 ; Ouchi et al, 2013 ; Vassart et al, 2013 ; Anjum et al, 2015 ; Buetti-Dinh et al, 2016 ; Liu et al, 2016 ; Haurat et al, 2017 ; Li et al, 2017 ; Schult et al, 2018 ; Wagner et al, 2018 ; Lemmens et al, 2019 ; Wang et al, 2019 ; Baes et al, 2020 ; Stracke et al, 2020 ; Suzuki et al, 2020 ; van der Kolk et al, 2020 ). To our knowledge, this is the first comprehensive collection of gene-regulator interactions compiled for S. acidocaldarius .…”

Physiological Characterization of Sulfolobus acidocaldarius in a Controlled Bioreactor Environment

“…The specific trehalose production was increasing in response to increasing dilution rates. This is a further indication for the role of trehalose production as part of a stress response [ 23 ]. Rising dilution rates put the cell under stress due to the growth rate approaching µ max and the organism is gradually approaching its maximal metabolic capacity [ 24 , 25 ].…”

Exogenous application of melatonin may contribute to enhancement of soybean drought tolerance via its effects on glucose metabolism

“…There is still evidence that they play an important role in stress resistance. For example, Glyma.09g073600 and Glyma.18g108100 regulate sucrose-related enzymes to increase resistance to low temperature stress [42]; Glyma.04g119700 regulates maltooligosyltrehalose under salt stress [43]; Glyma.12g054200 is considered to be a factor potentially involved in regulating the salt adaptation of α -galactosidase production [44]. In addition, Baud et al [45] and Santaniello et al [46] found that the Arabidopsis thaliana At3G43190 gene homologous to Glyma.09G073600, plays an important role in the regulation of sucrose synthase activity in plant sugar metabolism, whereas Chary et al [47] found that the At1G68020 homolog of Glyma.04G119700 affects Arabidopsis cellular morphology and plant structure via the activity of trehalose -6-phosphate synthase/phosphatase.…”