Phylogeny and Fatty Acid Profiles of New Pinnularia (Bacillariophyta) Species from Soils of Vietnam

A critical review of soil algae as a crucial soil biological component of high ecological and economic significance

Aero-terrestrial algae are ecologically and economically valuable bioresources contributing to carbon sequestration, sustenance of soil health, and fertility. Compared to aquatic algae, the literature on subaerial algae is minimal, including studies of distinctive habitats such as forest soils, agricultural fields, deserts, polar regions, specific subaerial zones, artificial structures, and tropical soils. The primary goal here was to identify the gaps and scope of research on such algae. Accordingly, the literature was analyzed per sub-themes, such as the "nature of current research data on terrestrial algae," "methodological approaches," "diversity," "environmental relationships," "ecological roles," and "economic significance." The review showed there is a high diversity of algae in soils, especially members belonging to the Cyanophyta (Cyanobacteria) and Chlorophyta. Algal distributions in terrestrial environments depend on the microhabitat conditions, and many species of soil algae are sensitive to specific soil conditions. The ecological significance of soil algae includes primary production, the release of biochemical stimulants and plant growth promoters into soils, nitrogen fixation, solubilization of minerals, and the enhancement and maintenance of soil fertility. Since aero-terrestrial habitats are generally stressed environments, algae of such environments can be rich in rare metabolites and natural products. For example, epilithic soil algae use wet adhesive molecules to fix them firmly on the substratum. Exploring the ecological roles and economic utility of soil and other subaerial algae could be helpful for the development of algae-based industries and for achieving sustainable soil management.

A new freshwater species of Pinnularia (Bacillariophyta) from Hunan Province, China

This study describes a new species of Pinnularia, P.hupingensissp. nov., on the basis of light and scanning electron microscope images. Pinnulariahupingensissp. nov. is characterised by its linear valve outline, extremely divergent striae, and very large hexagonal central area occupying ca. 1/5-1/8 of the valve length. The primary and secondary sides of the valve and the internal proximal raphe fissures are discussed. The new species is compared to similar taxa of the genus Pinnularia.

Description of five new Luticola D.G.Mann (Bacillariophyta, Diadesmidaceae) species from Indonesia with comments on the morphological boundaries of the genus

During a survey of the Indonesian diatoms, five Luticola D.G.Mann taxa that could not be identified, based on the available literature were discovered. Based on light microscopy, scanning electron microscope observations and comparisons with similar taxa, all of them are described as new species. All taxa were found on mosses growing on tree trunks and concrete on the islands of Banda Besar and Seram and from spring on Java Island. Luticolainsularissp. nov. is most similar to L.aequatorialis and L.simplex, but it can easily be distinguished from both taxa, based on the lower striae density, the narrower valves and the well-developed silica ridges on the valve face/mantle junction. Luticolabandanensissp. nov. resembles L.frequentissima, but they can be easily distinguished, based on their valve widths and the direction of the grooves located on the distal and proximal raphe endings. Luticolaellipticasp. nov. is most similar to L.sparsipunctata, L.tenuis and L.bryophila. Amongst all the species compared, L.ellipticasp. nov. is the only one with a highly asymmetrical central area, with the isolated pore located on the wider side. Luticolamalukuanasp. nov. shares similarities with L.dismutica and L.areolata, but it has a notably higher stria density. From L.areolata, it can also be separated by the morphology of striae and the lack of ghost areolae in the central area. Luticolapoliporeasp. nov. is unique in the whole genus due to the presence of multiple isolated pores.

Recent Advances in the Integrative Taxonomy of Plants

Biodiversity conservation and management call for rapid and accurate global assessments at the species level [...].

The Genus Pinnularia Ehrenberg (Bacillariophyta) from the Transbaikal Area (Russia, Siberia): Description of Seven New Species on the Basis of Morphology and Molecular Data with Discussion of the Phylogenetic Position of Caloneis

Seven Pinnularia species from the Transbaikal area, Russia, are described as new for science. These are P. baicalgenkalii, P. baicalflexuosa, P. microfrauenbergiana, P. pergrunowii, P. siberiosinistra, P. baicalodivergens, and P. baicalislandica. All species are described by original LM and SEM microphotographs and molecular phylogeny. We provide comparisons between the taxa and document variability in the features found in the species. The number of Pinnularia species in the Transbaikal area is the largest number of species of the genus anywhere in the world.

Luticola tenera sp. nov. (Diadesmidaceae, Naviculales)-A New Diatom from the Soil of the State Nature Reserve "Bastak" (Jewish Autonomous Region, Russia)

Diatoms inhabit different aquatic and non-aquatic environments, including soils. The naviculoid genus Luticola is widespread in various habitats and accounts for 264 species that are only based on morphological and morphometric characteristics. These parameters can greatly vary during the life cycle, making the species very similar to each other and complicating their unambiguous identification. During a study on soil algal diversity in the Russian Far East (Jewish Autonomous Region), we isolated a strain of naviculoid diatom and examined it using an integrative approach (phylogenetic, morphological, ultrastructural data, and life cycle). Phylogenetic analyses, based on chloroplast rbcL gene data, showed affinity of the new strain with the genus Luticola. Our alga shares morphological features typical of the genus members but differs from them by having valves with a larger width and hook-shaped external proximal raphe ends deflected to the side opposite the stigma. It was revealed that the strain reproduces via two types of sexual reproduction-isogamy and cis-anisogamy. Based on these phenotypic traits, we described the new isolate as Luticola tenera sp. nov.