Rocks represent a safeguard for microbial life under the persistent water scarcity and high solar radiation found in deserts. Indeed, microbial life establishes different types of lithic relationships, building microhabitats that allow microbes to thrive in the environmental conditions found in deserts. Hypolithic communities are the most common in Atacama Desert, and are dominated by cyanobacteria.
In the present work a cultivable clonal cyanobacterial strain from Atacama, namely Gloeocapsopsis sp. 1H9, was obtained. The main goal was to study the basis of its primitive multicellular behaviors, and to gain new insights into its cellular strategies for tolerating desiccation.
By means of complementary approaches (culturing, flow cytometry and microscopy), it was possible to determine that Gloeocapsopsis sp. 1H9 follows an intercellular organization pattern, which is associated to nutrient availability. The results presented in this work also indicate that the extracellular matrix of Gloeocapsopsis might play a fundamental role in the formation of multicellular colonies and the strategies to tolerate desiccation.
Moreover, depending on the prior nutritional conditions, this cyanobacterium might enter or not in a anhydrobiotic state (metabolic arrest).
In addition, this work provides the first draft genome of a cultivable hypolithic cyanobacterium from Atacama, providing the genomic framework for further functional molecular studies associated to desiccation tolerance and other stress avoidance strategies.
In spite of having received relatively minor attention to date, Gloeocapsopsis offers an appropriate model for solving long-standing questions such as primitive multicellular behaviors and tolerance to extreme environmental conditions, like desiccation.