Biology subjects

Szoevenyi, P.

Publications and source records attributed to Szoevenyi, P..

3 recordsLinked to original sources

bioRxiv2024

Molecular underpinnings of hornwort carbon concentrating mechanisms: subcellular localization of putative key molecular components in the model hornwort Anthoceros agrestis.

O_LIBiophysical carbon concentrating mechanisms (CCMs) operating at the single-cell level have evolved independently in eukaryotic algae and a single land plant lineage, hornworts. An essential component for an efficient eukaryotic CCM is a pyrenoid whose biology is well-characterized in the unicellular green alga, Chlamydomonas reinhardtii. By contrast, pyrenoids and CCM are little understood in hornworts. C_LIO_LIHere, we investigate the molecular underpinnings and dynamics of hornwort pyrenoids. We do so by studying the subcellular localization of candidate proteins homologous to essential CCM genes in C. reinhardtii and assessing their mobility kinetics in the hornwort model Anthoceros agrestis. C_LIO_LIWe provide evidence that an EPYC1 analog and the RuBisCO co-localize in the pyrenoid but pyrenoids seem less dynamic in A. agrestis than in C. reinhardtii. We further found that a carbon anhydrase homolog (CAH3) localizes to the pyrenoid, while an LCIB-like homolog is less intimately linked to the pyrenoid than in C. reinhardtii. C_LIO_LIOur results imply that the pyrenoid-based CCM of hornworts is characterized by a mixture of Chlamydomonas-like as well as hornwort-specific features which is in line with its independent evolutionary origin. Using these observations, we provide a first mechanistic model of hornwort CCM. C_LI

plant biology↗

bioRxiv2024

Systemic response to nitrogen starvation in the cyanobacteria hosting hornwort and liverwort provides little evidence for extensive priming to the cyanobiont

Mutualistic plant-microbe symbiotic interactions are thought to have evolved from a loose association between host plants and microbes when nutrients are limited. Therefore, the molecular network enabling intimate mutualistic plant-microbe symbioses may have evolved from a nutrient starvation response shared by all land plants. While the molecular link between nutrient status and symbiotic interaction is well-established, it remains poorly understood in some systems. This is especially true for the symbiotic associations between plants and cyanobacteria. To test the conservation of the starvation network across land plants as well as to investigate the link between nutrient starvation and symbiosis initiation in the plant-cyanobacteria symbiosis, here we explore the transcriptional responses to nutrient starvation in two non-vascular plant species, a hornwort Anthoceros agrestis and a liverwort Blasia pusilla, forming plant-cyanobacteria endophytic symbioses. We observe a deep conservation of the systemic starvation response across land plants. However, very few if any components of the starvation network appear to be specific to cyanobacteria hosting plants, providing little evidence for extensive and specific priming to the cyanobiont. Moreover, we found that some bioactive molecules known to be important in initiating the plant-mycorrhiza and nodule-forming bacteria symbioses, may also have a similar role in plant-cyanobacteria symbioses. HighlightOur results suggest that the most critical step in establishing plant-cyanobacteria interactions using non-host plants is the attraction of the cyanobiont. This finding has significant impact on crop engineering.

evolutionary biology↗

bioRxiv2022

Fern cell walls and the evolution of arabinogalactan-proteins in streptophytes

Significant changes have occurred in plant cell wall composition during evolution and diversification of tracheophytes. As the sister lineage to seed plants, knowledge on the cell wall of ferns is key to track evolutionary changes across tracheophytes and to understand seed plant-specific evolutionary innovations. Fern cell wall composition is not fully understood, including limited knowledge of glycoproteins such as the fern arabinogalactan-proteins (AGPs). Here, we characterize the AGPs from the leptosporangiate fern genera Azolla, Salvinia and Ceratopteris. The carbohydrate moiety of seed plant AGPs consists of a galactan backbone including mainly 1,3- and 1,3,6-linked pyranosidic galactose, which is conserved across the investigated fern AGPs. Yet, unlike AGPs of angiosperms, those of ferns contained the unusual sugar 3-O-methylrhamnose. Besides terminal furanosidic Ara (Araf), the main linkage type of Araf in the ferns was 1,2-linked Araf, whereas in seed plants 1,5-linked Araf is often dominating. Antibodies directed against carbohydrate epitopes of AGPs supported the structural differences between AGPs of ferns and seed plants. Comparison of AGP linkage types across the streptophyte lineage showed that angiosperms have rather conserved monosaccharide linkage types; by contrast bryophytes, ferns and gymnosperms showed more variability. Phylogenetic analyses of glycosyltransferases involved in AGP biosynthesis and bioinformatic search for AGP protein backbones revealed a versatile genetic toolkit for AGP complexity in ferns. Our data reveal important differences across AGP diversity which functional significance is unknown. This diversity sheds light on the evolution of the hallmark feature of tracheophytes: their elaborate cell walls. SIGNIFICANCE STATEMENTFerns are the sister lineage of seed plants and key to understanding plant evolution. To understand ferns unique cell walls, we analysed arabinogalactan-proteins from the fern genera Azolla, Salvinia and Ceratopteris. Comparison of AGP structures throughout the streptophyte lineage reveals special features in relation to systematic positions and proposes a trend to more hydrophilic AGPs in course of evolution. Through comparative genomic analyses, we pinpoint the potential genetic players for this diversity in cell walls.

plant biology↗