Abstract

Nostoc flagelliforme is a terrestrial macroscopic cyanobacterium with a hair-like appearance that is distributed in arid and semi-arid areas. It exhibits remarkable tolerance to extremely acute or long-term dehydration stress. However, it cannot withstand prolonged hydration or water saturation. It appears that too little water limits its growth while too much water becomes a burden. This seemingly contradictory situation is particularly pronounced in N. flagelliforme, reflecting its distinctiveness among Nosotcspecies with respect to the ways they adapt to dry environments. In this review, we call attention to potentially important drought-adaptation mechanisms in this species, including mechanisms related to its morphology, structure, ecophysiology and genetic background, summarizing the available studies relevant to this topic. This species may become a good model for investigating the diverse genetic mechanisms of Nostoc adaptation to dry environments.

Key words: Cyanobacteria, drought adaptation, dry environment, genetic mechanism, hydration cycle, Nostoc flagelliforme.