Fig. 6: Effect of osmotic and ionic stress on sugar and cell wall biology of zygnematophytes.
From: Systems acclimation to osmotic stress in zygnematophyte cells
a Log2 fold changes of metabolites from metabolite fingerprinting analysis of methanol-extracted samples after 9 hours of stress treatment with 0.8 M mannitol versus 0.15 M NaCl in positive ion mode. Identified metabolites are labeled. Log(P-values) are based on multiple sample test ANOVA with a permutation-based FDR set to 0.05 and S0 set to 0.15. b Long-term (26 days) effects of 0.15 M NaCl treatment on algae morphology. Left: Mesotaenium. Right, top: Zygnema after prolonged treatment. Right, bottom: Zygnema morphology after recovery for 14 days after 14 months of 0.15 M NaCl treatment. Pictures are representatives of six independent biological replicates of time-course experimentation; see supplemental Figure 8 for details. c Domain architecture, names, and IDs of proteins significantly more abundant (FDR < 0.05) during 0.15 M NaCl and/or 0.8 M mannitol treatments that have predicted arabinogalactan glycosylation sites. Species abbreviations: Me = Mesotaenium, Zc = Zygnema. d Arabinogalactan protein (AGP)-focused analysis of aqueous-extracted samples after 25 hours of 0.15 M NaCl or 0.8 M mannitol treatment. Top: β-Yariv radial diffusion assay. Bottom: Sugar epitope ELISA results. Signal intensities are normalized individually for each antibody to its respective maximum measured value. Right: Schematic representation of an AGP chain (not representative for Mesotaenium and Zygnema). e Staining of Mesotaenium with β-Yariv reagent after 25 hours of 0.15 M NaCl treatment, with quantification of extracellular β-Yariv-reactive material across different treatments plotted as box plot, where the box shows the interquartile range (IQR) from the 25th (Q1) to the 75th percentile (Q3) while the whiskers extend to minimum and maximum values in the data determined by Q1 – 1.5 × IQR to Q3 + 1.5 × IQR (data points outside are defined as outliers) the center line represents the mean. Each data point (see jitter) represents a biological replicate (n = 6). Source data are provided as a Source Data file. f Phylogenetic tree of glycosyl hydrolase family 16. The expanded clade represents subfamily 20, which includes xyloglucan endotransglucosylase/hydrolases (XTHs). The gene IDs in bold black indicate transcripts upregulated (ΔFC > 3) during osmotic stress, while those highlighted in orange correspond to proteins that are significantly more abundant (FDR < 0.05) under osmotic stress conditions. g Schematic representation of hypothesized major changes in cell wall components during osmotic and ionic stress in Zygnema and Mesotaenium. The respective enzymes showing significant changes at both protein and transcript levels are indicated. The depicted cell wall structure is hypothetical.
