Accumulation of trehalose in response to desiccation and salt stress in the terrestrial cyanobacterium Nostoc commune

Abstract

Changes in photosynthetic activity and trehalose levels in field-isolated, natural colonies of the terrestrial cyanobacterium Nostoc commune responding to desiccation and salt stress were investigated. As the water content decreased in N. commune colonies during desiccation, photosynthetic O2-evolving activity decreased and no activity was detected in desiccated colonies. A high level of O2 evolution was restored in the colonies as they absorbed atmospheric moisture, indicating that only a small amount of water is required for reactivation of photosynthesis. No detectable trehalose was found in fully hydrated N. commune colonies; however, trehalose accumulation occurred in response to water loss during desiccation and high levels of trehalose were detected in the airdried colonies. Moreover, a 0.2 M NaCl treatment also induced trehalose accumulation to a level equivalent to that by desiccation. Photosynthetic O2 evolution was inhibited by 0.2 M NaCl, indicating that N. commune can tolerate only low levels of salt. These results suggest that cessation of photosynthesis and trehalose accumulation occur in response to both matric water stress (desiccation) and osmotic water stress (high salt concentration), and that while trehalose may be a less effective osmoprotective compound than others, it is important for the extreme tolerance to desiccation observed in terrestrial cyanobacterium.

Trehalose and Abiotic Stress in Biological Systems

“…Nostoc commune is a terrestrial cyanobacterium that can survive more than a hundred years in desiccated state (Lipman, 1941;Cameron, 1962). When exposed to drought, in addition to the production of large amounts of extracellular polysaccharides, which have an important role in desiccation tolerance, N. commune also accumulate trehalose (Sakamoto et al, 2009;Klahn & Hagemann, 2011). Other cyanobacteria that accumulate trehalose during drought stress are Phormidium autumnale and Chroococcidiopsis sp.…”

“…(Hershkowitz et al, 1991). Trehalose synthesis is activated in response to water loss due to desiccation process, whereas when the water becomes available and the cells rehydrate trehalose content in the cells decreases (Sakamoto et al, 2009). Other cyanobacteria, like Anabena and Nostoc flagelliforme, accumulate trehalose but not in high enough quantities to be able to offer protection as a molecular chaperone.…”

Desiccation induced changes in osmolytes production and the antioxidative defence in the cyanobacterium Anabaena sp. PCC 7120

“…There are reports that drought and salt stress induce trehalose and sucrose accumulation in cyanobacteria (Hershkovitz et al 1991;Sakamoto et al 2009). The induction of trehalose synthesis in Anabaena sp.…”

Characterization of extracellular matrix components from the desiccation-tolerant cyanobacterium <i>Nostoc commune</i>

“…We have studied the desiccation tolerance in N. commune in physiological and biochemical terms (Matsui et al, 2011(Matsui et al, , 2012Morsy et al, 2008;Nazifi et al, 2013Nazifi et al, , 2015Sakamoto et al, 2009Sakamoto et al, , 2011Tamaru et al, 2005;Yoshida and Sakamoto, 2009;Wada et al, 2013Wada et al, , 2015.…”