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The genus Coelastrum Nägeli (Sphaeropleales; Scenedesmaceae) is a diverse genus of green algae with potential biotechnical applications. A sound understanding of its phylogeny will be a useful tool for predicting the distribution of traits that may enhance its utility, and may lead to a better understanding of its evolution and ecology. Here we present the plastome of Coelastrum microporum. Our exemplar was isolated from Gull Lake, Michigan and the complete plastome as assembled was 169,961 bp in length. The plastome contained 104 genes of which 68 were protein-coding genes (CDSs), 27 tRNA genes and three rRNA genes. The GC content of the plastome was 31.2%. The maximum likelihood phylogeny suggested that C. microporum was the sister group to a clade of single exemplars of three other genera in the Scenedesmaceae (Tetradesmus, Pectinodesmus and Coelastrella). [ABSTRACT FROM AUTHOR]

We describe the plastome of Jenufa minuta, a unicellular green alga whose precise relationship with the Sphaeropleales (Chlorophyceae) remains uncertain. This 206,680-bp genome contains 100 conserved genes, 11 of which exhibit 16 group I and seven group II introns. We discovered a trans-spliced group II intron in the rpl32 gene of J. minuta and its orthologs in all Sphaeropleales and several Chlamydomonadales; this is the first time this intron is documented. As in the mitochondria of J. minuta, the UGA codon is decoded as tryptophan. To our knowledge, this is the second report of a variant genetic code in plastids. [ABSTRACT FROM AUTHOR]

We sampled the first mitogenomes from a novel lineage of the Chlorophyceae that is sister to Sphaeropleales. Although the Jenufa perforata (27,180 bp) and Jenufa minuta (41,488 bp) mitogenomes differ markedly in size, gene order and intron content, their repertoires of conserved genes are essentially identical. Their rRNA genes display the same fragmentation patterns as their counterparts in Sphaeropleales. Their tRNA gene complements include two ancestral genes shared with Oedogoniales and Chaetophorales (Chlorophyceae) as well as a derived gene for a tRNA species decoding UGA as tryptophan. This noncanonical genetic code differs from those previously reported for Sphaeropleales. [ABSTRACT FROM AUTHOR]

Many species belonging to the coccoid green algae genus Coelastrella are considered potential candidates for the large-scale production of natural pigments and biofuels. However, little is known about the structural, functional and molecular aspects of the chloroplast genomes (cpDNAs) of this genus. In the present study, the complete sequence of the cpDNA of strain FACHB-2138, which was further identified as Coelastrella saipanensis Hanagata based on morphological and molecular analyses, was elucidated. The 196 140 bp cpDNA sequence that was assembled as a circular map was found to possess the typical quadripartite structure. The two identical copies of 11 897 bp inverted repeat (IR) sequences were separated from one another by single copy regions. The large single copy region (LSC) was 104 949 bp, whereas the small single copy region (SSC) was 67 397 bp. The cpDNA encoded a total of 96 unique genes, which included 67 protein-coding genes, three rRNA genes and 26 tRNA genes. A total of 19 group I introns were annotated in this genome. Comparative analyses with three species from the family Scenedesmaceae showed C. saipanensis had a slightly expanded genome, higher GC content and less skewed distribution of its genes between the two DNA strands than that of the other three species. The cpDNA data deduced from the present study helps to expand our present understanding of plant systematics and phylogenetic reconstruction, and identify the possible biotechnological applications of the species belonging to the studied taxa. [ABSTRACT FROM AUTHOR]

This article focuses on a detailed morphological and molecular analysis of the microscopic green alga Pediastrum alternans as it exhibits ambiguous morphology, questionable phylogenetic position and scattered distribution. The species, originally described from lakes close to the Baltic Sea in Denmark, was recently renamed Pseudopediastrum alternans based on rDNA sequencing of one culture from Namibia. In the present study, the African culture was morphologically and genetically compared with a culture identified as Ps. alternans from a coastal lake from northern Poland and a culture of Ps. boryanum var. longicorne from southern Poland. Conventional measurements, statistical and geometric morphometric analyses of the number of cells in coenobia, cell shape and size and wall ornamentation showed significant differences in the morphology of the three cultures. The analyses supported the phylogenetic distinction of the cultures based on rDNA and chloroplast DNA sequencing. Cultures of Pseudopediastrum alternans from Africa and Poland were not monophyletic. The African culture was moderately supported in a clade that could potentially represent a new species of Pseudopediastrum; whereas, the Polish culture formed a distinct lineage that was sister to some Ps. boryanum strains. The third culture, identified as Ps. boryanum var. longicorne, was nested within Ps. boryanum, as expected based on its morphology. Additional morphological comparison between the cultures and the iconotype showed that the Polish culture fits the description of Ps. alternans; whereas, the African one is so different from the iconotype that it cannot be called Ps. alternans. Analysis of plasticity of the Polish culture showed that its morphology is rather stable under varying nutrient and salinity conditions, and the culture cannot be misidentified as other Pseudopediastrum species. [ABSTRACT FROM AUTHOR]

We characterized the complete sequence of the mitochondrial genome of the freshwater green algal strain YC001, known as 'Ettlia sp.', which is of great interest for biofuel production. The size of the mitogenome was 52,489 base pairs (bp), with 49.0% GC content. It consisted of 49 mitochondrial genes typical of the Chlorophyceae, including 16 protein-coding genes, 27 transfer RNA genes and six ribosomal RNA genes as well as three introns within cox1 (6832 bp), rnlA (1805 bp) and cob (1107 bp). We determined that YC001 is a species of Coelastrella on the basis of molecular phylogenetic analyses and microscopic observations. A unique feature of this mitogenome is the presence of three different types of inverted repeats between tmh and tml and between nadA and cox1 as well as the presence of orfl7555, and one additional copy of the trnM gene, all of which enable a comparison with an available sister taxon, Acutodesmus obliquus. [ABSTRACT FROM AUTHOR]

A new species of the chlorophycean genus Desmodesmus, D. baconii, was described based upon analyses of the morphology of the coenobia and DNA sequences from the nuclear ribosomal 18S RNA gene and the internal transcribed spacer region. Desmodesmus baconii was unusual in that it possessed two rows of spines only on the terminal cells. This species was easily distinguished from other Desmodesmus taxa with two rows of spines by the point symmetry of the coenobia and the lack of rows of spines on median cells of four-celled coenobia. Spines tapered from prominent incurved spines near one pole to small spines at the opposite pole. Median cells and the pole of terminal cells opposite the large spines had two or three short spines. Cell sizes were slightly larger for two-celled (4.2-6.7 μm × 1.6-2.9 μrn) than for four-celled coenobia (3.2-6.5 μm × 1.2-4.5 μm). Results of analyses of DNA sequence data indicated that D. baconii, although a member of the monophyletic genus Desmodesmus, was not closely allied with any other Desmodesmus taxon. Desmodesmus baconii was isolated from hypereutrophic Lake Chicot in Arkansas, USA, and is not known from any other location [ABSTRACT FROM AUTHOR]