Advances in Cyanobacterial Biology

Prashant Kumar Singh, Ajay Kumar, Vipin Kumar Singh, Alok Kumar Shrivistava

• Publisher: Academic Press
• Year: 2020
• ISBN:
  9780128193129
• Topic: Technology & Engineering
• Subtopic: Agronomy
• Index: Technology & Engineering

Advances in Cyanobacterial Biology presents the novel, practical, and theoretical aspects of cyanobacteria, providing a better understanding of basic and advanced biotechnological application in the field of sustainable agriculture. Chapters have been designed to deal with the different aspects of cyanobacteria including their role in the evolution of life, cyanobacterial diversity and classification, isolation, and characterization of cyanobacteria through biochemical and molecular approaches, phylogeny and biogeography of cyanobacteria, symbiosis, Cyanobacterial photosynthesis, morphological and physiological adaptation to abiotic stresses, stress-tolerant cyanobacterium, biological nitrogen fixation. Other topics include circadian rhythms, genetics and molecular biology of abiotic stress responses, application of cyanobacteria and cyanobacterial mats in wastewater treatments, use as a source of novel stress-responsive genes for development of stress tolerance and as a source of biofuels, industrial application, as biofertilizer, cyanobacterial blooms, use in Nano-technology and nanomedicines as well as potential applications.

This book will be important for academics and researchers working in cyanobacteria, cyanobacterial environmental biology, cyanobacterial agriculture and cyanobacterial molecular biologists.

• Summarizes the various aspects of cyanobacterial research, from primary nitrogen fixation, to advanced nano-technology applications
• Addresses both practical and theoretical aspects of the cyanobacterial application
• Includes coverage of biochemical and molecular approaches for the identification, use and management of cyanobacteria

Chapter 1

Cyanobacterial imprints in diversity and phylogeny

Swati Mishra, Department of Botany, Institute of Sciences, Banaras Hindu University, Varanasi, India

Abstract

Cyanobacteria are known as architects of Earth’s atmosphere. The global importance of cyanobacteria is well established because of their worldwide distribution and abundance in the myriad possible niche as well as their contribution to atmospheric oxygen. In spite of a long evolutionary history of cyanobacteria, only a fraction of their diversity has been addressed in recent times through molecular methods.

The classical taxonomy emphasized on the morphological identification of cyanobacteria. Although it provides critical information such as accurate taxonomic identification and quantitative data, the process is relatively time-consuming and requires experienced taxonomists. Also, certain noteworthy phenotypic changes, which may occur in natural assemblages as well as in laboratory environments,make the morphological identification often more challenging even to experienced taxonomists. In recent years, several valuable phenotypic, especially ultramorphological, features, such as cell wall perforations, have been confirmed to be stable and reliable taxonomic characters.

To reconstruct evolutionary relationships among cyanobacterial species, a specific set of marker genes usually 16S rDNA, rpoB, phycocyanin locus, internal transcribed spacer region, and nif genes, have been used widely in cyanobacteria. These specific target sequences represent variations and allow identification of similarities or dissimilarities in organisms. Therefore the molecular approaches applied, with classical single and multilocus phylogenetic taxonomy methods, on the one hand, and the rapid identification of cyanobacterial diversity within environmental samples, on the other, have been investigated with high-throughput next-generation sequencing methods, without considering their taxonomic status in depth.

Moreover, the molecular techniques, such as DNA barcoding, metagenomic analysis, and quantitative polymerase chain reaction (PCR), have also been applied for the identification and quantification of cyanobacteria. In the present scenario, completely sequenced genomes of several cyanobacterial species have uncut information about the cell. Therefore taxonomists have suggested that phylogenetic reconstructions should be considered more reliable to resolve phylogenetic interest, provided they are based on entire genomes.

A multitude of taxonomists have used a varied number of genes for analysis, but very few have tried to combine data into a unified data set for a comprehensive analysis. In this context, combined analysis (analysis of extensive concatenated data set from several single-gene data sets) has been suggested in cyanobacteria, which up until recently has been applied only intermittently.

Keywords

Cyanobacteria; diversity; morphology; phylogeny; systematics; taxonomy

1.1 Introduction

Cyanobacteria are an ancient lineage of a morphologically diverse group of bacteria that primarily shaped the Earth through the oxygenic photosynthesis evolution, and they continue to play an essential role in the global carbon and nitrogen cycles (Shih et al., 2013). With estimated global biomass of 3×10¹⁴ g C, or 10¹⁵ g wet biomass (Garcia-Pichel et al., 2003), quantitatively cyanobacteria are the world’s most significant organisms (Whitton, 2012). Inferred from morphological similarities, the rare fossil record suggests an age of about 3.5 billion years for the cyanobacterial lineage (Schopf, 2000). During their long evolutionary history, these organisms have been able to adapt geochemical and climate changes as well as anthropogenic disturbances (Paerl and Otten, 2013). Among all photosynthetic organisms, cyanobacteria, possibly exhibit the most comprehensive range of diversity in growth habitats, and CO₂-concentrating mechanisms adapted their niches in various environmental vulgarizations (Badger et al., 2006).

In terms of productivity, cyanobacteria contribute ~50% of the ocean’s primary productivity. The diversity expressed apparently by their morphological (Fig. 1.1), biochemical, and physiological assets, which enable them to persist and settle in a wide range of habitats (extreme to moderate) (Falkowski, 2012). Moreover, several cyanobacterial species are utilized for different roles as important bioindicators to recognize the quality of environmental (Mateo et al., 2015; Monteagudo and Moreno, 2016) as well as essential toxins (Dittmann et al., 2013) and other secondary metabolites producers, which are highly biotechnological (Abed et al., 2009; Ducat et al., 2011) and pharmaceutically critical (Vijayakumar and Menakha, 2015). Beyond that, cyanobacteria can live in some of the extreme habitats on the Earth (Seckbach, 2007).

Figure 1.1 Various cyanobacterial life forms (a,b,d,e,g,h,j,k) filamentous and (c,f,i) coccoid-colonial life forms.

In spite of long cyanobacterial research history in botany and microbiology, only an insignificant portion of cyanobacterial diversity till date has been explored as well as addressed by molecular and phylogenetic methods. However, many other cyanobacterial species remain to be discovered (Nabout et al., 2013), which needs further research in this area.

1.2 Biodiversity of cyanobacteria

The ubiquitous availability, with distinct morphological features, makes cyanobacteria the most significant oxygenic photosynthetic prokaryotes with a long evolutionary history. During the course of evolution, cyanobacteria have adapted almost every ecological niche, including the most extreme ones (Schopf, 2000) such as hot springs (Ferris et al., 2003), a frozen lake in Antarctica (Gordon et al., 2000), hypersaline environments (Dor et al., 1991), and hot desserts (Budel and Wessels, 1991). They have also been tremendously influential in shaping the course of evolution and ecological change throughout Earth’s history.

In addition to their potential applications in agriculture, as nutrient supplements, biofertilizer, plant growth–promoting rhizobacteria, and in industry, as biocontrol agents and biofuel, they are utilized as food supplements/nutraceuticals, in bioremediation, as plastic biodegradation and wastewater treatment as well. Moreover, they produce a wide array of bioactive compounds (secondary metabolites) with diverse biological activities (such as antiviral, antibacterial, antifungal, antimalarial, antitumor, and antiinflammatory).

In spite of having variety of significances, cyanobacteria still face the challenge of an appropriate classification system and infer lacking exact systematic ranking of several taxa. Since the beginning of the cyanobacterial research, taxonomy and classification have always been challenging. Also, biodiversity, phylogeny, and taxonomy of cyanobacteria have remained paradoxical (Pinevich, 2008). Therefore cyanobacterial taxonomy requires a consensus approach (Palinska and Surosz, 2014) to realize the actual biodiversity status of this group. This chapter summarizes our current knowledge of cyanobacterial biodiversity as well as phylogenetic and taxonomic researches, with focus on the comparison between various taxonomic and phylogenetic systems.

1.3 Morphological diversity–based classification

Cyanobacteria, characterized with oxygenic photosynthesis and share ecological niches with eukaryotic algae, prompted their treatment in the phycological circles, hence, called blue-green algae, which possess various morphological features varied widely (such as spherical, ovoid, and cylindrical) unicellular species, as well as multicellular colonial and filamentous forms. Due to the tremendous variation in shape and size among the cyanobacteria, morphological features are considered more useful classification criteria than for any other group of prokaryotes. Therefore morphological attributes have chosen to determine their taxonomic distinction in classical taxonomic approaches. Earlier, Geitler (1932) utilized morphological features for identification and introduced 1500 species and 150 genera, whereas Drouet (1981) accepted only nine genera based on ecophysiological criteria. Geitler (1932) mentioned that cyanobacteria possess up to four different cell types, forms. The unicellular (Gloeothece), colonial (Gloeocapsa) as well as simple filamentous forms (Scytonema), or complex truly branched forms (Stigonema).

An alternative system was developed by Drouet and Daily (Drouet, 1981), which drastically reduced the number of genera and species of blue-green algae. It was hypothesized that many morphological differences seen in natural samples are ephemeral and that various cyanobacterial species are different “ecophenes” of real taxa. However, this system was unable to reflect the true genetic diversity among blue-greens and was never entirely accepted because the morphological features are highly variable and often dependent on environmental factors or culture conditions (Pearson and Kingsbury, 1966).

In spite of having limitations, cyanobacterial classification still follows mostly the criteria of morphological traits at the higher taxonomic ranks, often combined with ecology in the lower taxonomic ranks (Geitler, 1932; Boone et al., 2001; Anagnostidis and Komárek, 1985, 1988, 1990; Komárek and Anagnostidis, 1989).

Desikachary (1959) identified different species of cyanobacteria base...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Chapter 1. Cyanobacterial imprints in diversity and phylogeny
• Chapter 2. Cyanobacterial diversity: molecular insights under multifarious environmental conditions
• Chapter 3. Cyanobacteria in tropical and subtropical marine environments: bloom formation and ecological role
• Chapter 4. Database resources for cyanobacterial research
• Chapter 5. Cyanobacterial pigments and their fluorescence characteristics: applications in research and industry
• Chapter 6. Cyanobacterial membrane biology under environmental stresses with particular reference to photosynthesis and photomorphogenesis
• Chapter 7. Iron homeostasis of cyanobacteria: advancements in siderophores and metal transporters
• Chapter 8. Molecular chaperones in protein folding and stress management in cyanobacteria
• Chapter 9. Cyanobacterial genome editing toolboxes: recent advancement and future projections for basic and synthetic biology researches
• Chapter 10. Impact of pesticides applications on the growth and function of cyanobacteria
• Chapter 11. Cyanoomics: an advancement in the fields cyanobacterial omics biology with special reference to proteomics and transcriptomics
• Chapter 12. Algae and cyanobacteria as a source of novel bioactive compounds for biomedical applications
• Chapter 13. Cyanobacterial stress-responsive small RNAs (sRNAs): players of stress and developmental responses
• Chapter 14. Physiological aspects of cyanobacterial nitrogen fixation and its applications in modern sciences
• Chapter 15. Ultraviolet-screening compound mycosporine-like amino acids in cyanobacteria: biosynthesis, functions, and applications
• Chapter 16. Heterocyst and akinete differentiation in cyanobacteria: a view toward cyanobacterial symbiosis
• Chapter 17. Cyanobacterial peroxiredoxins and their role in cyanobacterial stress biology
• Chapter 18. Cyanobacteria as a biofuel source: advances and applications
• Chapter 19. Cyanobacteria: as a promising candidate for heavy-metals removal
• Chapter 20. Dynamics of harmful cyanobacterial blooms and their toxins: environmental and human health perspectives and management strategies
• Chapter 21. Cyanobacteria as a source of nanoparticle: application and future projections
• Chapter 22. Role of algae and cyanobacteria in bioremediation: prospects in polyethylene biodegradation
• Chapter 23. Cyanobacteria: potential source of biofertilizer and synthesizer of metallic nanoparticles
• Chapter 24. Cyanobacteria: a potential source of anticancer drugs
• Chapter 25. Cyanobacteria as a source of biofertilizers for sustainable agriculture
• Index