Cyanobacteria

From Basic Science to Applications

A.K. Mishra,D.N. Tiwari,A.N. Rai

• Verlag: Academic Press
• Jahr: 2018
• ISBN:
  9780128146682
• Thema: Sciences biologiques
• Thema: Microbiologie

Cyanobacteria constitute the most widely distributed group of photosynthetic prokaryotes found in almost all realms of the earth and play an important role in Earth's nitrogen and carbon cycle. The gradual transformation from reducing atmosphere to oxidizing atmosphere was a turning point in the evolutionary history of the earth and made conditions for present life forms possible.

Cyanobacteria: From Basic Science to Applications is the first reference volume that comprehensively discusses all aspects of cyanobacteria, including the diverse mechanisms of cyanobacteria for the advancement of cyanobacterial abilities, towards higher biofuel productivity, enhanced tolerance to environmental stress and bioactive compounds and potential for biofertilizers.

• Describes cyanobacterial diversity, stress biology, and biotechnological aspects of cyanobacteria
• Explores the global importance of cyanobacteria
• Provides a broad compilation of research that deals with cyanobacterial stress responses in both controlled laboratory conditions as well as in their natural environment

Chapter 1

Cyanobacteria in Diverse Habitats

Lira A. Gaysina^⁎,†; Aniket Saraf^‡; Prashant Singh^{§ ⁎} Department of Bioecology and Biological Education, M. Akmullah Bashkir State Pedagogical University, Ufa, Russian Federation
^† All-Russian Research Institute of Phytopathology, Moscow, Russian Federation
^‡ Department of Botany, Ramniranjan Jhunjhunwala College, Mumbai, India
^§ Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Abstract

Cyanobacteria are an enormously diverse group of prokaryotes whose adaptive capacity along with the ability to tolerate extreme conditions makes them omnipresent. They are found in almost all the habitats of the Earth where life can be imagined to have flourished. Cyanobacteria are present in a wide range of habitats viz. marine, freshwater, soil, biological soil crusts, snow, cryoconites, etc. Further, they are found in symbiotic association with different hosts and also occur in extreme stressed conditions like volcanic ash, salted soils, and anthropogenically disturbed areas. This chapter explores the diversity of cyanobacteria from different habitats and enlists the dominant groups inhabiting these habitats. The diversity of cyanobacteria from different climatic zones; temperate, tropical as well as Polar Regions have been reviewed and documented in this chapter. The taxonomic complexity of cyanobacteria has hindered the capture of the actual biodiversity which is evident from the fact that the reported diversity encompasses only the traditional cyanobacterial genera. Morphological plasticity, ecological flexibility, and huge amount of heterogeneity are responsible for the confusions surfacing the cyanobacterial taxonomy. In this chapter, we also discuss the current trends in cyanobacterial taxonomy which would be essential in the studies conducted to capture the biodiversity of cyanobacteria from different habitats.

Keywords

Cyanobacteria; Biodiversity; Plankton; Benthos; Biological soil crusts; Volcanic ash; Disturbed areas; Salted soils; Polar Regions; Polyphasic approach; Prochlorococcus; Synechococcus; Nodularia; Nostoc; Microcoleus vaginatus

Acknowledgments

This work was supported by the Russian Foundation for Basic Research in the frame of project 16-04-01511 а. PS and AS thank the Department of Science and Technology (DST-SERB) for the project PS/YSS/000879. The authors are thankful to Jeffry R. Johansen for valuable discussion, and Yunir Gabidullin for helping us in the preparation of the figure plates.

1 Introduction

Cyanobacteria are oxygen evolving, gram-negative, photoautotrophic bacteria that can be found in virtually all imaginable habitats across the world. They can be found in habitats extending from the extremely cold deserts of the Arctic and Antarctic Zones (Mataloni and Komárek, 2004) to the very extreme hot springs of the Yellowstone National Park, thus representing an interesting form of life in a wide range of aquatic and terrestrial environments (Whitton and Potts, 2000a,b). This extraordinary expanse of cyanobacteria is actually a result of an important character that the cyanobacteria can boast of which we refer to as “adaptability.” Their amazing success in adapting to such diverse and varying habitats can be attributed to a very long-standing evolutionary history that cyanobacteria enjoy. Some of the modern physiological and anatomical features of cyanobacteria that have helped in supporting their long history on Earth include an extremely high tolerance level of low oxygen and free sulfide, the ability to utilize H₂S as a photoreductant in place of H₂O, and the strong tolerance capacity for ultraviolet B and C radiations (Whitton and Potts, 2000a,b). Thus, these are some of the major adaptive features that have allowed the cyanobacteria to grow, flourish, and dominate in habitats where many other forms of life are absolutely unknown or may struggle to even survive.

Interestingly, the origin of cyanobacteria and their basic anatomical features are typical bacterial type but their ecological, biological, and morphological features are quiet specific and diverse too (Flores et al., 2006; Kalaitzis et al., 2009; Flores and Herrero, 2010). The almost essential possession of some interesting features like the ability of buoyancy, performing oxygenic photosynthesis, and fixation of atmospheric nitrogen (Walsby, 1994; Castenholz, 2001; Burja et al., 2001; Berman-Frank et al., 2003) make the cyanobacteria more special and capable to adapt to varied conditions in both normal and stressed habitats. As a consequence of such strong survival capabilities, they also act as prominent phototrophic primary producers in natural ecosystems (Field et al., 1998; Bryant, 2003).

Cyanobacteria have played a major role in the evolution of different forms of life on Earth. The anaerobic earth was converted to the aerobic one by the cyanobacteria about 2 billion years ago, thus finally supplying oxygen to the atmosphere through oxygenic photosynthesis for approximately 1.5 billion years (Berman-Frank et al., 2003; Schopf et al., 1983). This event of oxygenation of the Earth’s atmosphere allowed for an enormous degree of greater diversification of many forms of life on the Earth. Apart from the oxygenation, cyanobacteria also influenced the advancement of life on Earth by shaping up themselves as the progenitors of chloroplasts (Giovannoni et al., 1988; Sergeev et al., 2002), ultimately leading to a broader diversification of algae and land plants.

In the current times, the cyanobacteria still continue to affect the life on Earth, as the major oxygen producers on this planet. Apart from being the major oxygen producers, many of them are also efficient fixers of atmospheric nitrogen thus making them extremely important components of nutrient-deprived ecosystems and extreme environments all throughout the Earth. As a result of their high adaptive capacity, cyanobacteria are also well known to form a wide range of nitrogen-fixing symbiotic relationships with representatives from almost all plant groups such as algae (Hemiaulus hauckii-Richelia intracellularis) fungi (Geosiphon pyriforme-Nostoc), bryophytes (Anthoceros-Nostoc), pteridophytes (Azolla-Anabaena), gymnosperms (Cycas-Nostoc), and angiosperms (Gunnera-Nostoc), thus supplying the host organisms with a lot of fixed nitrogen and in return, acquiring carbohydrates from the host (Morot-Gaudry and Touraine, 2001), thus allowing the host organisms to grow in regions where they may otherwise not survive at all.

Cyanobacterial diversity owing to their adaptive capacities occupies incredibly large canvas of the planet Earth. The expanse of their diversi...