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PubMed2026

Dual Roles of RAD23b and RAD4 on the Desiccation Tolerance of Germinated Seeds.

Desiccation tolerance (DT) is a survival trait enabling orthodox seeds to withstand extremely low water content. While some protective factors are characterised, it remains mechanistically obscure. Here, based on PEG-induced DT re-establishment in germinated Brassica napus L. seeds, we investigated the dual functions of nucleotide excision repair (NER) components RAD23b and RAD4 in DNA repair and transcriptional regulation of root development. PEG pre-treatment alleviated dehydration-induced DNA damage and activated NER genes, suggesting the involvement of NER in seed DT. Unexpectedly, Arabidopsis atrad23b mutant and BnRAD23b/BnRAD4 over-expressing seeds all exhibited significantly decreased DT after dry back, which evoked a hypothesis that BnRAD23b-BnRAD4 functions beyond NER. Normally, BnRAD4 interacted with BnRAD23b and repressed the expression of root development genes NAC103, EMB1444, RRA1 by directly binding to STRE elements within their promoters. Dehydration stress alleviated this repression, drove transcriptional reprogramming and might redirect the complex to execute DNA repair. Genetic analyses revealed that germinated seeds of atnac103, atemb1444, and atrra1 single mutants all exhibited reduced DT, and double mutants under atrad23b background almost abolished DT. This study suggests that RAD23b and RAD4 may regulate DT re-establishment of germinated seeds through balancing genome integrity and radicle development, with implications for DT study broadly.

Brassica napus L.↗
PubMed2025

Phosphoproteomics analysis provides novel insight into the mechanisms of extreme desiccation tolerance of the desert moss Syntrichia caninervis.

Syntrichia caninervis is a model species for research on desiccation tolerance (DT) because it is capable of rapidly responding to drastic changes in water conditions. Phosphorylation, a key post-translational modification process that is rapid and reversible, enables the rapid regulation of protein functions, aiding plants to quickly adapt to changing environments. Modifications to phosphorylation may play a crucial role in the DT of S. caninervis, although no studies have been published. Here, we report a 4D label-free high-resolution dynamic proteomic and phosphoproteomic analysis of S. caninervis during dehydration and rehydration, allowing for the quantification of 2854 proteins and 1177 phosphoproteins, including 1447 differentially expressed proteins (DEPs) and 699 differentially phosphorylated proteins (DPPs). Among the phosphoproteins, 36.5% displayed changes in protein abundance. The proteomic and phosphoproteomic changes involved proteins (DEPs and DPPs) that were mainly involved in photosynthesis, glutathione metabolism, the citrate cycle, and the biosynthesis of secondary metabolism pathways during dehydration. During rehydration, DEPs and DPPs were mainly associated with processes related to ribosome and energy metabolism. In summary, during dehydration, phosphorylation mainly regulates signal transduction and metabolic processes, allowing plants to adapt to a loss of water. During rehydration, phosphorylation controls repair and recovery mechanisms, restoring metabolic activity and reestablishing cellular functions. ScDHAR1, a protein involved in glutathione metabolism, was differentially phosphorylated at two serine sites (S29 and S218) in response to desiccation. Further analysis revealed that phosphorylation of S29/S218 in ScDHAR1 significantly increased its enzymatic activity, thereby enhancing the DT of S. caninervis in situ. This work establishes a phosphoprotein database for a DT moss. These findings not only broaden our understanding of S. caninervis DT but also fill knowledge gaps in the field of phosphoproteomics in DT mosses, while providing valuable data resources for future related research.

Phosphoproteins↗
PubMed2026

Radiation-resistant and desiccation-tolerant bacteria from the Chavara-Neendakara high background radiation area, india: phenotypic characterisation and genomic insights.

Radiation-resistant microorganisms that survive high doses of ionising radiation serve as valuable models for understanding stress adaptation; however, the genomic determinants underlying extreme radiation tolerance in bacteria from natural environments with high background radiation remain insufficiently characterised. Bacterial isolates from the Chavara-Neendakara HBRA (Kerala, India) were evaluated for desiccation tolerance, and the desiccation-resistant isolates were subsequently exposed to gamma irradiation (1-10 kGy) using a 60Co source. Isolates were identified through 16S rRNA sequencing, morphologically characterised by FE-SEM, and screened for antibiotic susceptibility. The highly radiation-resistant strain underwent whole-genome sequencing via Oxford Nanopore Technology, with De novo assembly, polishing, and genome annotation. Four bacterial isolates (Micrococcaceae and Paenibacillaceae) exhibited D10 values of 1-7 kGy, including one multidrug-resistant strain; no endospores were observed in the Paenibacillus isolate under the tested conditions. Paenibacillus sp. HBRA004 survived 10 kGy gamma radiation, exceeding all previously reported HBRA isolates by over fourfold. Its 5.0 Mbp genome (GC = 48.27%, ≥ 99% completeness) encodes five mechanistically independent DNA repair pathways; homologous recombination (recA, recN, radA), base excision repair (mutM, mutY, mutT), mismatch repair (mutL, mutS), nucleotide excision repair (uvrA, uvrB, uvrD), and non-homologous end joining (ku, ligD), alongside a redundant antioxidant network comprising triple-copy Fe/Mn-family superoxide dismutases and ahpC peroxiredoxin. A thioredoxin system (trxA, trxB, msrA) and manganese uptake via mntH may contribute to further layers of ROS defence. Their specific contribution to the HBRA004 phenotype remains to be experimentally and comparatively validated. These findings represent the first genomically characterised 10 kGy-resistant bacterial isolate from the Chavara-Neendakara HBRA, establishing a new benchmark for radiation tolerance within this ecologically significant environment. Pathway depth, gene copy amplification, and Mn/Fe homeostasis appear to be candidate mechanisms contributing to high-level radiation tolerance, consistent with patterns in other radiation-resistant taxa, though their contribution requires functional validation.

India↗
PubMed2026

Site-specific gene integration by recombinase-mediated cassette exchange in anhydrobiotic Pv11 cells.

Pv11 cells, derived from Polypedilum vanderplanki, uniquely tolerate complete desiccation (anhydrobiosis). Although a CRISPR/Cas9-based precise integration method (CRIS-PITCh) has been developed for Pv11 cells, a CRISPR-free strategy that fixes both the genomic locus and transgene copy number has not yet been established. Here, we implement recombinase-mediated cassette exchange (RMCE) in Pv11 cells and generate master cell lines that retain anhydrobiosis following genetic engineering. We first evaluated the activity of multiple site-specific recombinases in Pv11 cells using a transient two-plasmid reporter assay. Flp, Cre, and Bxb1 recombinases all excised a test cassette and activated a green fluorescent protein (GFP) reporter, whereas phiC31 integrase mediated recombination at the DNA sequence level but did not induce reporter expression under our construct configuration. To enable genomic RMCE, we inserted an FRT/FRT3-landing pad (LP) into a previously identified genomic safe-harbor locus using CRIS-PITCh and isolated clonal master cell lines by single-cell sorting. Using the established master line, Flp-based RMCE achieved site-specific cassette exchange at the LP, producing HaloTag fluorescence and drug resistance upon successful exchange. In addition, the expected post-exchange sequence was confirmed by sequencing. We further established an all-in-one RMCE vector combining the Flp recombinase and donor cassette on a single plasmid. Together, these results demonstrate locus-defined, single-copy transgene integration in anhydrobiotic Pv11 cells via RMCE and provide a standardized, CRISPR-free workflow for routine genetic manipulation in this unique cell line. This workflow facilitates both fundamental research and applied biotechnological applications using desiccation-tolerant cells.

Anhydrobiosis↗
PubMed2026

Phenylacetic acid mediates Acinetobacter baumannii entry into a viable but non-culturable state.

Desiccation tolerance is central to the pathogenic success of the opportunistic pathogen Acinetobacter baumannii, allowing its survival on hospital surfaces in the absence of water and nutrients for months at a time, compromising surface decontamination and aiding cross-contamination between staff and patients. Despite the importance of desiccation tolerance, the regulation underpinning this behaviour remains largely elusive. In this work, transcriptomic analyses of desiccated cells revealed phenylacetic acid (PAA) catabolism as an essential mediator of desiccation tolerance. We subsequently demonstrate that deletion of the paa operon abolished the clonogenicity of desiccated cells. Strikingly, these A. baumannii cells remained viable by entering the viable but non-culturable (VBNC) state, a means to survive extreme stressors like antibiotic exposure. Furthermore, we uncover that PAA catabolism is necessary to mediate PAA-driven biofilm regulation. These findings highlight PAA catabolism as a modulator of biofilm formation and a key pathway for entry into the VBNC state in response to desiccation. This reveals PAA catabolism as a target for novel infection prevention strategies.

Phenylacetates↗
PubMed2026

Sulfide-oxidizing potential and hypersalinity tolerance strategies in salt-crust covered coastal microbial mats.

Hypersaline microbial mats are dense microbial ecosystems capable of performing nearly complete element cycling under harsh conditions including near-saturation salinity. Our previous study of salt-crust-covered microbial mats showed that oxygenic photosynthesis was inhibited at salt saturation, while phototrophic sulfide oxidation persisted despite well-known sulfide-oxidizing taxa being undetectable. In this study, we analyzed metagenome-assembled genomes (MAGs) from the same mats to identify sulfide-oxidizing taxa and adaptations enabling oxygenic phototrophs to survive salt saturation. We extended the dataset by including morphologically identical mats exposed to lower salinity regimes to identify metabolic capabilities specifically selected for by saturation-level salinity. The phototrophic sulfide oxidation capability was found in nearly all cyanobacterial MAGs, in some Chloroflexota, and in abundant Rhodovibrio populations previously not known to oxidize sulfide. Furthermore, we found clear indications of Haloarchaea-like potassium-based osmoregulation in Bradymonadaceae (Myxococcota) adding another taxon to the few known potassium-accumulating bacteria. Despite lower oxygen concentrations, salt-crust-covered mats showed smaller proportions of fermenters and higher proportions of aerobic microorganisms than lower-salinity mats. We compared the genetic signatures of hypersalinity and desiccation tolerance in cyanobacterial MAGs from this study to genomes from desiccation-prone environments such as desert soils and small freshwater streams. Genomes of hyperhalophilic cyanobacteria were characterized by lack of certain potassium transporters and catalase genes and presence of additional osmolyte transporter subunits and sulfide-oxidation genes. We hypothesize that during salt saturation the oxidative stress for mat dwelling cyanobacteria is lowered, while the ability to oxidize sulfide provides them with energy when oxygenic photosynthesis is inhibited.

Oxidation-Reduction↗
PubMed2026

The R2R3-MYB transcription factor ScMYB20 negatively regulates drought and salt tolerance through a dual-repression of ScCHALCONE SYNTHASE-1 (ScCHS1)-mediated flavonoid biosynthesis in the desert moss Syntrichia caninervis.

The desert moss Syntrichia caninervis is one of the most desiccation-tolerant land plants known and provides a powerful system for dissecting the molecular foundations of extreme stress adaptation in early-diverging land lineages. The MYB transcription factor superfamily orchestrates secondary metabolism and stress signaling across plants, yet its lineage-specific evolution and mechanistic deployment in bryophytes remain poorly understood. Here, we identified 65 ScMYB genes in the S. caninervis genome and showed that the family expanded predominantly through dispersed duplication, with no detectable synteny to vascular-plant MYBs, indicating bryophyte-specific neo-functionalization. Integrating phylogenetic clustering, cis-element architecture and stress-responsive expression profiling, we pinpointed ScMYB20, a nuclear-localized, S13-subgroup R2R3-MYB that is rapidly and strongly induced by dehydration and salinity. Heterologous overexpression in Arabidopsis, together with overexpression and RNAi in S. caninervis, demonstrated that ScMYB20 negatively regulates drought and salt tolerance by suppressing antioxidant capacity, osmotic adjustment and photosynthetic performance, while concomitantly elevating ROS and MDA accumulation. Mechanistically, ScMYB20 directly binds a TAACCA motif in the ScCHS1 promoter to repress its transcription, and simultaneously sequesters the WD40 protein ScTTG1, a positive transcriptional activator of ScCHS1, thereby antagonising ScTTG1-mediated activation. Transient ScCHS1 overexpression restored flavonoid accumulation, antioxidant capacity and stress tolerance. Together, our findings define a dual-repression module (ScMYB20-ScTTG1-ScCHS1) that fine-tunes flavonoid flux under abiotic stress, and provide evolutionary and mechanistic insights into how R2R3-MYB repressors evolved to balance metabolic investment and stress survival in land plants.

Syntrichia caninervis↗
PubMed2025

Comprehensive identification and analysis of clusters of tandemly duplicated genes reveal their contributions to adaptive evolution of green plants.

Tandem gene duplication occurred more frequently compared with the episodic whole-genome duplication (WGD), providing a continuous supply of genetic material for evolutionary innovation and adaptation to changing environments. The rising roles of clusters of tandemly duplicated genes (CTDGs) in the evolution of phenotypic diversity have been unraveled in mammals. However, the content and biological roles of CTDGs remain largely unknown in plants. Here, we comprehensively identified CTDGs in 220 published plant genomes representing major lineages of green plants. The number of CTDGs showed great variation across taxa, ranging from 0 to 6028. The size of CTDGs varied from 2 to 47 genes, with small clusters containing two members predominating. Interestingly, significant expansion of CTDGs was found in early-diverging land plants and is closely associated with the evolution of key traits (e.g., ABA response, plant cuticle, UV-B resistance) required for plants to conquer terrestrial environments. Functional enrichment analysis revealed conserved and specialized functional profiles among different sizes of CTDGs in both Arabidopsis thaliana and the bryophyte Physcomitrium patens. Small CTDGs were enriched in fundamental stress responses, including protein modification, signal transduction, and responses to diverse stress stimuli, while large CTDGs were enriched in more sophisticated processes such as plant hormone biosynthesis and signaling, plant-microbe interactions, and reproductive processes. Expression pattern analyses of CTDGs under different stress conditions in A. thaliana and P. patens revealed that the highest number of CTDGs showed differential expression under drought stress, suggesting important roles of CTDGs in the evolution of desiccation tolerance in early land plants. The results of this study provide new additions to our knowledge about the abundance of CTDGs across green plants and reveal their important contributions to enable plants to overcome stressful environments on land.

Gene Duplication↗
PubMed1979

Soil stabilization by a prokaryotic desert crust: implications for Precambrian land biota.

A cyanophyte dominated mat, desert crust, forms the ground cover in areas measuring hundreds of square meters in Utah and smaller patches in Colorado. The algal mat shows stromatolitic features such as sediment trapping and accretion, a convoluted surface, and polygonal cracking. Sand and clay particles are immobilized by a dense network of filaments of the two dominating cyanophyte species, Microcoleus vaginatus and M. chthonoplastes, which secrete sheaths to which particles adhere. These microorganisms can tolerate long periods of desiccation and are capable of instant reactivation and migration following wetting. Migration occurs in two events: 1. immediately following wetting of dry mat, trichomes are mechanically expelled from the sheath as it swells during rehydration, and 2. subsequently, trichomes begin a self-propelled gliding motility which is accompanied by further production of sheath. The maximum distance traveled on solid agar by trichomes of Microcoleus vaginatus during a 12 hour period of light was 4.8 cm. This corresponds to approximately 500 times the length of the fastest trichome, and provides a measure of the potential for spreading of the mat in nature via the motility of the trichomes. Dehydration resistence of the sheath modifies the extracellular environment of the trichomes and enables their transition to dormancy. Following prolonged wetting and evaporative drying of the mat in the laboratory, a smooth wafer-like crust is formed by the sheaths of Microcleus trichomes that have migrated to the surface. Calcium carbonate precipitates among the algal filaments under experimental conditions, indicating a potential for mat lithification and fossilization in the form of a caliche crust. It is suggested that limestones containing tubular microfossils may, in part, be of such an origin. The formation of mature Precambrian soils may be attributable to soil accretion, stabilization, and biogenic modification by blue-green algal land mats similar to desert crust.

Cyanobacteria↗
PubMed1976

Plant desiccation: polysome loss not due to ribonuclease.

During desiccation of the drought-tolerant moss Tortula ruralis polysome levels decline substantially before any increase in ribonuclease activity is observed. Furthermore, ribosomes in the desiccated moss are not complexed with messenger RNA fragments. It is concluded that ribosome runoff and failure to re-form an initiation complex mediate polysome loss during desiccation.

Peptide Chain Initiation, Translational↗
PubMed2026

Genome-wide analysis of FATA associated with drought tolerance in tetraploid potato (Solanum tuberosum).

The cuticle represents the outer most protective barrier against biotic and abiotic stresses. It is composed of cutin and waxes and protects plants from desiccation, UV, cold, mechanical stresses, and pathogens. GWAS/BSAseq combined with SeqSNP analyses in an association panel of 34 potato cultivars had revealed that the acyl-ACP thioesterase FATA (Soltu.DM.06G033680.1) is significantly associated with drought tolerance in potato. Apart from three FATB genes, only one FATA gene is present in potato that has the highest homology to FATA2 in Arabidopsis. FATA is responsible for the export of C18:1 fatty acid from chloroplast into cytosol, which is necessary for the biosynthesis of cutin. A knockout mutant of AtFATA2 was analyzed with regard to the cuticle permeability and to drought tolerance as well as recovery. Loss of FATA function leads to higher sensibility to water deficit in Arabidopsis, but to no change in recovery. The increased permeability of the cuticle in the fata2 knockout mutant as shown indirectly by higher chlorophyll leaching might play a role in this. Haplotypes for FATA were identified for the two potato cultivars Albatros and Désirée. All Désirée haplotypes and Albatros haplotypes 1, 3 and 4 were also revealed by former potato pan genome studies, while Albatros haplotype 2 is unique and has not been described before. Protein models were developed to investigate the influence of different SNPs in the haplotypes on the predicted protein structure and especially the substrate cavity. In potato, protein modeling suggests that only the hypothetical isoform B of FATA might be able to process oleoyl-ACP, but not hypothetical isoform A. However, this hypothesis needs to be verified by enzyme activity assays.

FATA↗
PubMed1979

Isolation of radiation-resistant bacteria without exposure to irradiation.

Resistance to desiccation was utilized in the selection of highly radiation-resistant asporogenous bacteria from non-irradiated sources. A bacterial suspension in phosphate buffer was dried in a thin film at 25 degrees C and 33% relative humidity. Storage under these conditions for 15 days or more reduced the number of radiation-sensitive bacteria. Further selection for radiation-resistant bacteria was obtained by irradiation of bacteria on velveteen in the replication process, thereby avoiding the toxic effect of irradiated media. The similarity of radiation resistance and identifying characteristics in irradiated and non-irradiated isolates should allay some concerns that highly radiation-resistant bacteria have been permanently altered by radiation selection.

Acinetobacter↗
PubMed1976

Prostatic desiccation used in poor-risk patients with benign and malignant prostatic obstruction.

A small percentage of patients with infra-vesical obstruction cannot tolerate open or transurethral prostatectomy. In these cases cryoprostatectomy is a possibility, we have, however, used another method based on heat destruction of the tissue. The results in 24 poor-risk patients were satisfactory, without any serious postoperative complications, and with excellent long-term results in 80% of the cases. The only complication is a high rate of incontinence. Until this problem has been solved the procedure should be reserved for poor-risk patients.

Aged↗