A Timescale for the Radiation of Photosynthetic Eukaryotes

Abstract

Oxygenic photosynthesis is considered the most important evolutionary innovation in the history of Earth. It depends on two photosystems, responsible for the photolysis of water and the reduction of carbon dioxide. Oxygen and carbohydrates are released at the end of the reaction. Extraordinary, the oxygen released created the stratospheric ozone layer, and transformed the ocean chemistry, whereas the carbohydrates are the primary source of energy for complex cells. Several lines of evidence indicate the photosynthesis arose in the ancestors of cyanobacteria. It was spread over some eukaryotes by the acquisition of a freeliving cyanobacterium, which evolved into photosynthetic plastid, the chloroplast. The timing of the chloroplast emergence is still controversy.Estimated ages range from 600 to 2100 million years ago (Mya) in accordance to previous studies.The aim of this study is to clarify several aspects of the origin and diversification of photosynthetic eukaryotes. For this purpose, we utilized a data set based on 27 proteincoding genes from genomes of cyanobacteria and photosynthetic eukaryotes, more genes than other papers that also utilized plastid genes, and performed the Bayesian analysis method to estimate the divergence times of the photosynthetic eukaryotes. Results showed photosynthetic eukaryotes emerged Late Mesoproterozoic about 1342 Mya. The Early Proterozoic oceans did not have adequate conditions for eukaryotes, because chemical elements such as zinc and molybdenum were at reduced concentrations, and they are essential to the formation of eukaryotic proteins.

Phylogenomic fingerprinting of tempo and functions of horizontal gene transfer within ochrophytes

“…These comprise several "crown supergroups," some of which (e.g., opisthokonts, including animals and fungi) are exclusively nonphotosynthetic, while others (e.g., archaeplastids, including plants, and stramenopiles) contain photosynthetic members (1,2). Within these photosynthetic eukaryotes, the initial endosymbiotic acquisition of a chloroplast occurred (3,4) in a common ancestor of the archaeplastids (green algae and plants, red algae, and glaucophytes), which has subsequently been transmitted into other photosynthetic groups (e.g., cryptomonads, haptophytes, ochrophytes within the stramenopiles, and dinoflagellates) via secondary and tertiary endosymbioses (5,6). Alongside endosymbiotic transfers, nonendosymbiotic or horizontal gene transfers (HGTs) from bacteria and eukaryotes have shaped the biology of individual eukaryotic groups (7,8).…”

“…The ochrophytes are a diverse group of algae, spanning from single-celled pico-phytoplankton of no more than a few microns diameter (e.g., chrysophytes, pelagophytes), to giant macroalgae of over 100 m in length (e.g., kelps, within the phaeophytes) (5,9), and originating over 500 million years ago (3,4). Ochrophytes constitute well over half of the photosynthetic eukaryote barcodes retrieved in the Tara Oceans census of marine planktonic life (10), and have important roles as producers and consumers in freshwater habitats (11,12).…”

In-process real-time probiotic phenotypic strain identity tracking: The use of Fourier transform infrared spectroscopy

“…Even though DNA-based techniques were successful in typing L. plantarum at interspecies and intraspecies levels (Evanovich et al, 2019;Manzoor and Tayyeb, 2019;Yu et al, 2021), some phenotypic variations associated with the cell surface can be eluded. In this context, it is necessary to highlight the cell membrane-associated capability of L. plantarum of resisting acid, heat, and other stresses (Capozzi et al, 2011;Ricciardi et al, 2012).…”

Characteristics of the carbon cycle in late Mesoproterozoic: Evidence from carbon isotope composition of paired carbonate and organic matter of the Shennongjia Group in South China

“…Therefore, the residence time of this organic matter is much longer than that of eukaryotic organic matter, and much of it would be remineralized in the water column, inducing low forg (e.g., Butterfield, 2009;Lenton et al, 2014). (Evanovich and Guerreiro, 2020) and organic-walled microfossils records of the late Mesoproterozoic. The distribution of microfossil assemblages was collected from the ~1350 Ma Xiamaling Formation (Miao et al, 2021), ~1350-1150 Ma Sarda and Avadh formations (Prasad and Asher, 2001), >1250 Ma Kamo Group (Nagovitsin, 2009), ~1300-1200 Ma Thule Supergroup (Samuelsson et al, 1999) and ~1100 Ma Atar/El Mreïti Group (Beghin et al, 2017.…”

“…For example, multiple types of fossils have been observed during this time interval, including the crown groups of Rhodophyta and Chlorophyta, respectively represented by the fossils Bangiomorpha pubescens and Proterocladus antiquus, as well as possible fungal fossils Opisthokonta giraldae (Butterfield, 2001;Loron et al, 2019;Tang et al, 2020). Meanwhile, phylogenetic data also suggest that the diversification of photosynthetic eukaryotes occurred during the late Mesoproterozoic (Yoon et al, 2004(Yoon et al, , 2010Parfrey et al, 2011;Yang et al, 2016;Sanchez-Baracaldo et al, 2017;Evanovich and Guerreiro, 2020;Strassert et al, 2021). These emerging scenarios are substantially different from the biological evolutionary stasis hypothesized for the boring billion (Buick et al,1995;Brasier and Lindsay, 1998;Butterfield and Smith, 2015).…”