Diversity of Cyanobacteria and Algae in Erodited Soils of the Fergana Valley (Uzbekistan) According to Light Microscopy Data and High-Throughput Sequencing

Abstract

For the first time, comparative data on the taxonomic composition of cyanobacterial and algal communities of eroded soils in the Fergana Valley (Uzbekistan), which were obtained using morphological analysis and microbiological profiling, are presented. The characteristic features of the algal flora of the eroded soils of the Rezoksai ravines, compared to the soils of the Levye Hills, were the presence of yellow–green algae, the absence of heterocytic cyanobacteria capable of nitrogen fixation, an increase in the proportion of monadic forms and/or algae capable of zoosporogenesis, and generally lower taxonomic richness and diversity of algae. Light microscopy was shown to confirm in part the diversity of cyanobacteria and algae in the studied soils estimated by high-throughput sequencing, but only detected in about half of the taxa. However, the presence of yellow–green algae was demonstrated solely by light microscopy and not by metabarcoding. The use of the V3–V4 region of the chloroplast 16S rRNA gene allowed us additionally to identify genera of green algae in the algal flora such as Edaphochlorella, Pseudomuriella, Watanabea, as well as diatoms of the genera Bacillaria, Fistulifera, Entomoneis, and charophyte algae Klebsormidium. Nevertheless, approximately 20% of algae remain unidentified due to the lack of reference sequences for the green microalgae ITS2 in genetic databases.