Dinoflagellates: a remarkable evolutionary experiment

Abstract

In this paper, we focus on dinoflagellate ecology, toxin production, fossil record, and a molecular phylogenetic analysis of hosts and plastids. Of ecological interest are the swimming and feeding behavior, bioluminescence, and symbioses of dinoflagellates with corals. The many varieties of dinoflagellate toxins, their biological effects, and current knowledge of their origin are discussed. Knowledge of dinoflagellate evolution is aided by a rich fossil record that can be used to document their emergence and diversification. However, recent biogeochemical studies indicate that dinoflagellates may be much older than previously believed. A remarkable feature of dinoflagellates is their unique genome structure and gene regulation. The nuclear genomes of these algae are of enormous size, lack nucleosomes, and have permanently condensed chromosomes. This chapter reviews the current knowledge of gene regulation and transcription in dinoflagellates with regard to the unique aspects of the nuclear genome. Previous work shows the plastid genome of typical dinoflagellates to have been reduced to single-gene minicircles that encode only a small number of proteins. Recent studies have demonstrated that the majority of the plastid genome has been transferred to the nucleus, which makes the dinoflagellates the only eukaryotes to encode the majority of typical plastid genes in the nucleus. The evolution of the dinoflagellate plastid and the implications of these results for understanding organellar genome evolution are discussed.

Evolutionary linkage between eukaryotic cytokinesis and chloroplast division by dynamin proteins

“…Hatena arenicola (Katablepharidophyta) bears a close evolutionary relationship with cryptophytes, in which permanent chloroplasts are established (25). A similar situation has been observed in Dinoflagellata (26) and Cercozoa (27), in which certain species have established the division synchronization, whereas others still have a transient endosymbiotic relationship with photosynthetic eukaryotes or cyanobacteria. The above observations suggest that division synchronization was necessary for the establishment of permanent chloroplasts (13).…”

Unfolding the secrets of coral–algal symbiosis

“…Dinoflagellates are characterized by a very large genome (Hackett et al, 2004) and a number of unique features such as DNA containing 5-hydoxymethylmuracil (Rae, 1976), a lack of the usual histones (Rizzo, 1981) and transcriptional regulatory elements (Li and Hastings, 1998). Dinoflagellates contain a conserved spliced leader sequence (Zhang et al, 2007), and highly expressed genes with elevated copy numbers and tandem repeats (Bachvaroff and Place, 2008).…”

Dinoflagellates: Ecological Approaches and Spatial Distributions in Malaysia Waters

“…Dinoflagellates are differentiated from one another by the pattern of thecate or amphiesma which is made up of cellulose plates that protect the cells from the tugor pressure [1,3]. Previous study on the fossils of ancient dinoflagellates revealed six patterns of plate that classified the species into different major groups; gymnodinoid, suessioid, peridinioid, gonyaulacoid, dinophysoid, and prorocentroid [4].…”

“…Photosynthetic products are important for the continuum of coral metabolism, growth, reproduction and survival [10,16,17]. This is because oxygen-byproduct of dinoflagellates fuels up the rate of calcification by the reef-building corals [1,10]. In return, the reefs provide protection for zooxanthelle against grazers and free access of nutrients in the nutrient-poor environment [16].…”

“…Phytoplankton contributes a lot in the food web of the marine ecosystem due to its role as primary producer in the food web. Dinoflagellates are a type of phytoplanktons, categorized under Kingdom Protista and further grouped into phylum Pyrrophyta as it is a single-celled organism with flagella [1].…”