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PubMed1997

[Icelandic moss lozenges in the prevention or treatment of oral mucosa irritation and dried out throat mucosa].

BACKGROUND: Icelandic Moss (Cetraria islandica) has been used to treat inflammation and dryness of the pharyngeal mucosa in the naturopathy for many years. It contains substances with protective and antiinflammatory effects for the oral mucosa. The necessary concentration of Icelandic Moss and its therapeutic effectiveness were analysed in this clinical study. METHODS: Sixty-one patients who recently underwent surgery of nasal septum were evaluated for this randomized study. These patients suffer especially from dryness and inflammation of the oral cavity due to breathing only through the mouth while the nose is permanently closed by a nasal package. Three groups of patients treated with three different concentrations of the active substance were compared, Coating, dryness, and inflammation of the mucosa, lymph nodes, tongue, the tolerance of the drug, and symptoms like hoarseness and sore throat were documented. The oral application was performed from the first to the fifth day after the operation. RESULTS: The treatment with Icelandic Moss caused a direct reduction of the observed pathological changes. There were no significant differences between the three test groups. A dose of 0.48 g per day (10 Isla-Moos lozenges per day) is a sufficient treatment. CONCLUSIONS: Icelandic Moss is an advisable therapeutic opportunity without interactions and side effects for the treatment of inflammation of the oral mucosa occurring after nasal surgery, after intubation, and for simple infections of the throat.

Adolescent↗
PubMed2006

Analysis of mosses and soils for quantifying heavy metal concentrations in Sicily: a multivariate and spatial analytical approach.

BACKGROUND: The use of vegetal organisms as indicators of contamination of the environment is partially replacing traditional monitoring techniques. Amongst the vegetal organisms available, mosses appear to be good bioindicators and are used for monitoring anthropogenic and natural fall-out on soils. This study has two objectives: the evaluation of the concentrations of heavy metals in soils and mosses of the Sicily Region, in Italy and the identification of the origin of fall-out of heavy metals. METHODS: Mosses and the surface soil were sampled at 28 sites, only the youngest segments of Hylocomium splendens and Hypnum cupressiforme, corresponding to the plant tissues produced during the last 3 years, were taken. The elements Cd, Cu, Ni, Pb and Zn were analysed by ICP-MS and Hg by AAS. Statistical analysis was by PCA and spatial representation by GIS. RESULTS AND DISCUSSION: In the mosses sampled in Sicily, the highest concentrations of Cd were found around the cities of Palermo and Messina. The highest concentrations of Hg were recorded in the northern part of the island between Trapani and Messina, similar to the distribution of Cu. Different areas with the highest concentrations of Ni were found near the south coast, in the vicinity of Palermo and around the Volcano Etna. The highest concentrations of Pb were found in the south-west coast near Agrigento, where important chemical plants and petroleum refineries are located. Except for a few locations, Zn fall-out was found to be evenly distributed throughout Sicily. CONCLUSION: The sites where the concentrations of heavy metals cause greatest concern have been revealed by the PCA analysis and portrayed using GIS. Also of some concern is the diffuse and anthropogenic origin of Hg and Cd. The combined approach of using soil and mosses, together with pedological interpretation and application of multivariate statistical techniques has provided valuable insight into the environmental aspects of heavy metal deposition in a region of southern Europe. RECOMMENDATIONS AND OUTLOOK: Further insight into the deposition of heavy metals will require more detailed sampling of soils and mosses in both new and previous study areas. This needs to be complemented by detailed pedological investigations in the study areas. Future research programmes will address these issues.

Air Pollution↗
PubMed2006

Pilot study on road traffic emissions (PAHs, heavy metals) measured by using mosses in a tunnel experiment in Vienna, Austria.

BACKGROUND, AIMS AND SCOPE: Over the last few years there has been extensive research for new indicators providing information about deposition resulting from road traffic and tunnel experiments received special attention in emission research. Mosses have been used for the estimation of atmospheric heavy metal and PAH depositions for more than three decades, although they were used only a few times for estimating ambient air pollution caused by traffic. In the current study, the suitability of using a moss species for monitoring road traffic emissions inside a tunnel was evaluated. This was a first-time ever attempt to use plants (mosses) as bioindicators in a tunnel experiment. Specifically, two relevant questions were examined: 1) Do mosses accumulate toxic substances derived from road traffic emissions under the extremely adverse conditions which can be found in a tunnel, and 2) Which substances can mainly be attributed to road traffic emissions and therefore be taken as efficient and reliable indicators for motor vehicles? METHODS: For the first time a biomonitor (the moss species Hylocomium splendens (Hedwig) B.S.G.) was used in a road tunnel experiment to analyse emissions from road traffic. Moss samples were exposed for four weeks in wooden frames (size 10 cm x 10 cm), covered by a thin plastic net with a mesh size of 1 cm x 1 cm. 17 elements, mainly heavy metals, and the 16 EPA-PAHs together with coronene were analysed by ICP-AES, AAS and GC-MSD. RESULTS: Enrichment factors, calculated by comparing post-experiment concentrations to those of a background site, were high for most PAHs, especially benzo(g,h,i)perylene (150.7), coronene (134.7), benzo(a)anthracene (125.0), indeno(1,2,3-c,d)pyrene (79.8), chrysene (78.1), pyrene (69.6) and benzo(b)-fluoranthene (67.4), and among the other elements for Sb (73.1), Mo (59.6), Cr (33.9), As (24.1), Cu (19.6), and Zn (17.1). All these substances can thus be taken as indicators for road traffic pollution. Concentrations were also significantly higher in the tunnel mosses for all investigated substances than along busy roads outside tunnels. Cluster analysis revealed groups of substances which could sensibly be attributed to various sources (abrasion processes, Diesel combustion) and enrichment in the various particle size classes. DISCUSSION: The extreme high concentrations in the analysed moss samples from inside the tunnel were due to higher concentrations in the ambient tunnel air, and the fact that already deposited chemical substances are not lost by rain, as well as efficient uptake capacities even under the extremely adverse conditions in a tunnel. In accordance with previous studies our results suggest that PAHs are better indicators for emissions from the burning process than heavy metals. CONCLUSIONS: As in open fields, mosses are suitable indicators for monitoring traffic emissions in tunnels. In addition to biomonitoring in open fields, in tunnel experiments mosses are even better indicators, because the confounding effects of other sources of pollution and the 'noise' in the accumulation process (e.g. washout through wet deposition) are minimised. The results of our study demonstrate the usefulness of mosses for surveying heavy metals and PAH emissions and deposition arising from road traffic sources, even under the extremely adverse conditions of the tunnel environment. RECOMMENDATION: It can be considered that biomonitors like mosses are a suitable alternative to technical particle filters inside tunnels. They are easy to handle, low in costs and valuable information regarding traffic emissions can be obtained. PERSPECTIVE: The results of this pilot-study proved the feasibility of the method, however, should be corroborated by further investigations based on a sample set that allows for generalization of the findings and might even include other moss species. A comparison of technical measurements with the biomonitoring method could lead to a more general acceptance of the results.

Air Pollutants↗
PubMed2002

The organization of Physcomitrella patensRAD51 genes is unique among eukaryotic organisms.

Genetic recombination pathways and genes are well studied, but relatively little is known in plants, especially in lower plants. To study the recombination apparatus of a lower land plant, a recombination gene well characterized particularly in yeast, mouse, and man, the RAD51 gene, was isolated from the moss Physcomitrella patens and characterized. Two highly homologous RAD51 genes were found to be present. Duplicated RAD51 genes have been found thus far exclusively in eukaryotes with duplicated genomes. Therefore the presence of two highly homologous genes suggests a recent genome duplication event in the ancestry of Physcomitrella. Comparison of the protein sequences to Rad51 proteins from other organisms showed that both RAD51 genes originated within the group of plant Rad51 proteins. However, the two proteins form a separate clade in a phylogenetic tree of plant Rad51 proteins. In contrast to RAD51 genes from other multicellular eukaryotes, the Physcomitrella genes are not interrupted by introns. Because introns are a common feature of Physcomitrella genes, the lack of introns in the RAD51 genes is unusual and may indicate the presence of an unusual recombination apparatus in this organism. The presence of duplicated intronless RAD51 genes is unique among eukaryotes. Studies of further members of this lineage are needed to determine whether this feature may be typical of lower plants.

Animals↗
PubMed2004

Targeted knockout in Physcomitrella reveals direct actions of phytochrome in the cytoplasm.

The plant photoreceptor phytochrome plays an important role in the nucleus as a regulator of transcription. Numerous studies imply, however, that phytochromes in both higher and lower plants mediate physiological reactions within the cytoplasm. In particular, the tip cells of moss protonemal filaments use phytochrome to sense light direction, requiring a signaling system that transmits the directional information directly to the microfilaments that direct tip growth. In this work we describe four canonical phytochrome genes in the model moss species Physcomitrella patens, each of which was successfully targeted via homologous recombination and the distinct physiological functions of each gene product thereby identified. One homolog in particular mediates positive phototropism, polarotropism, and chloroplast movement in polarized light. This photoreceptor thus interacts with a cytoplasmic signal/response system. This is our first step in elucidating the cytoplasmic signaling function of phytochrome at the molecular level.

Base Sequence↗
PubMed2006

Cryptic species within the cosmopolitan desiccation-tolerant moss Grimmia laevigata.

The common cushion moss Grimmia laevigata (Bridel) Bridel grows on bare rock in a broad range of environments on every continent except Antarctica. As such, it must harbor adaptations to a remarkably broad set of environmental stresses, the extremes of which can include very high temperatures, prolonged nearly complete desiccation, and high ultraviolet B (UVB) exposure. Yet, like many mosses, G. laevigata shows very little morphological variability across its cosmopolitan range. This presents an evolutionary puzzle, the solution to which lies in understanding the phylogeographic structure of this morphologically simple organism. Here we report the results of an analysis of amplified fragment length polymorphisms (AFLPs) in G. laevigata, focusing on individuals from the California Floristic Province. We found evidence that populations within California constitute two distinct geographically overlapping cryptic species. Each clade harbors multiple private alleles, indicating they have been genetically isolated for some time. We suggest that the existence of cryptic species within G. laevigata, in combination with its life history, growth habits, and extreme desiccation tolerance, makes this moss an ideal research tool and a candidate for a biological indicator of climate change and pollution.

Bryopsida↗
PubMed2006

Genes for the peptidoglycan synthesis pathway are essential for chloroplast division in moss.

The general consensus is that a cyanobacterium phagocytosed by a host cell evolved into the plastids of red and green algae, land plants, and glaucophytes. In contrast to the plastids of glaucophytes, which retain a cyanobacterial-type peptidoglycan layer, no wall-like structures have been detected in plastids from other sources. Although the genome of Arabidopsis thaliana contains five genes that are essential for peptidoglycan synthesis, MurE, MurG, two genes for D-Ala-D-Ala ligase (Ddl), and the gene for translocase I (MraY), their functions have not been determined. We report that the moss Physcomitrella patens has nine homologous genes related to peptidoglycan biosynthesis: MurA, B, C, D, E, and F, Ddl, genes for the penicillin-binding protein Pbp, and dd-carboxypeptidase (Dac). Corroborating a computer prediction, analysis of the GFP fusion proteins with the N terminus of PpMurE or of PpPbp suggests that these proteins are located in the chloroplasts. Gene disruption of the PpMurE gene in P. patens resulted in the appearance of macrochloroplasts both in protonema and in leaf cells. Moreover, gene knockout of the P. patens Pbp gene showed inhibition of chloroplast division in this moss; however, no Pbp gene was found in A. thaliana.

Arabidopsis↗
PubMed2003

Comparative genomics of Physcomitrella patens gametophytic transcriptome and Arabidopsis thaliana: implication for land plant evolution.

The mosses and flowering plants diverged >400 million years ago. The mosses have haploid-dominant life cycles, whereas the flowering plants are diploid-dominant. The common ancestors of land plants have been inferred to be haploid-dominant, suggesting that genes used in the diploid body of flowering plants were recruited from the genes used in the haploid body of the ancestors during the evolution of land plants. To assess this evolutionary hypothesis, we constructed an EST library of the moss Physcomitrella patens, and compared the moss transcriptome to the genome of Arabidopsis thaliana. We constructed full-length enriched cDNA libraries from auxin-treated, cytokinin-treated, and untreated gametophytes of P. patens, and sequenced both ends of >40,000 clones. These data, together with the mRNA sequences in the public databases, were assembled into 15,883 putative transcripts. Sequence comparisons of A. thaliana and P. patens showed that at least 66% of the A. thaliana genes had homologues in P. patens. Comparison of the P. patens putative transcripts with all known proteins, revealed 9,907 putative transcripts with high levels of similarity to vascular plant genes, and 850 putative transcripts with high levels of similarity to other organisms. The haploid transcriptome of P. patens appears to be quite similar to the A. thaliana genome, supporting the evolutionary hypothesis. Our study also revealed that a number of genes are moss specific and were lost in the flowering plant lineage.

Arabidopsis↗
PubMed1995

Effects of mechanical signaling on plant cell cytosolic calcium.

Mechanical signals are important influences on the development and morphology of higher plants. Using tobacco transformed with the Ca(2+)-sensitive luminescent protein aequorin, we recently reported the effects of mechanical signals of touch and wind on the luminescence and thus intracellular calcium of young seedlings. When mesophyll protoplasts are isolated from these transgenic tobacco plants and mechanically stimulated by swirling them in solution, cytoplasmic Ca2+ increases immediately and transiently up to 10 microM, and these transients are unaffected by an excess of EGTA in the medium. The size of the transient effect is related to the strength of swirling. Epidermal strips isolated from transgenic tobacco leaves and containing only viable guard cells and trichomes also respond to the strength of swirling in solution and can increase their cytoplasmic Ca2+ transiently up to 10 microM. Finally, the moss Physcomitrella patens containing recombinant aequorin exhibits transient increases in cytoplasmic Ca2+ up to 5 microM when swirled in solution. This effect is strongly inhibited by ruthenium red. Our data indicate that the effect of mechanical stimulation can be found in a number of different cell types and in a lower plant as well as tobacco and suggest that mechanoperception and the resulting increase in cytoplasmic Ca2+ may be widespread.

Aequorin↗
PubMed1996

G proteins regulate dihydropyridine binding to moss plasma membranes.

The role of calcium as an activator and regulator of many biological processes is linked to the ability of the cell to rapidly change its cytoplasmic calcium levels. Calcium acts as an intracellular messenger in hormone-induced bud formation during the development of the moss Physcomitrella patens. Calcium transport and ligand binding studies have implicated plasma membrane-localized 1, 4-dihydropyridine (DHP)-sensitive calcium channels in this increase in cellular calcium. To understand the regulation of the moss calcium channel, we investigated the involvement of GTP binding regulatory proteins (G proteins). Guanosine 5'-(gamma-thio)triphosphate (GTPgammaS), a nonhydrolyzable GTP analog that locks G proteins into their active state, stimulated DHP binding to high affinity receptors in the moss plasma membrane. DHP binding was measured as the ability of the DHP agonist Bay K8644 or the DHP antagonist nifedipine to compete with the DHP arylazide [3H]azidopine for binding to moss plasma membranes. G protein stimulation of binding was seen when competition was carried out with either nifedipine or Bay K8644. G proteins regulated the rates of association and dissociation of bound [3H]azidopine, and stimulation was dependent on GTPgammaS concentration. Guanosine 5'-(beta-thio)diphosphate, a GDP analog that locks G proteins into their inactivated state, did not affect the dose dependence of either the agonist or the antagonist. These results suggest that G proteins may act via a membrane-delimited pathway to regulate calcium channels in the moss plasma membrane.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1999

Isolation of a germin-like protein with manganese superoxide dismutase activity from cells of a moss, Barbula unguiculata.

A novel extracellular Mn-superoxide dismutase (SOD) was isolated from a moss, Barbula unguiculata. The SOD was a glycoprotein; the apparent molecular mass of its native form was 120 kDa, as estimated by gel filtration chromatography, and that of its monomer was 22,072 Da, as estimated by time of flight mass spectroscopy. The protein had manganese with a stoichiometry of 0.80 Mn/monomer. The cDNA clone for a gene encoding the extracellular Mn-SOD was isolated. Sequence analysis showed that it has a strong similarity to germin (oxalate oxidase) and germin-like proteins (GLPs) of several plant species and possesses all the characteristic features of members of the germin family. The clone encoding this extracellular Mn-SOD was therefore designated B. unguiculata GLP (BuGLP). BuGLP had no oxalate oxidase activity. In addition, the cDNA for a gene encoding the moss mitochondrial Mn-SOD was isolated. Its amino acid sequence had little similarity to that of BuGLP, even though a close similarity was observed among the mitochondrial Mn-SODs of various organisms. BuGLP was the first germin-like protein that was really demonstrated to be a metalloprotein with Mn-SOD activity but no oxalate oxidase activity.

Amino Acid Sequence↗
PubMed2002

Functional knockout of the adenosine 5'-phosphosulfate reductase gene in Physcomitrella patens revives an old route of sulfate assimilation.

The reduction of adenosine 5'-phosphosulfate (APS) to sulfite catalyzed by adenosine 5'-phosphosulfate reductase is considered to be the key step of sulfate assimilation in higher plants. However, analogous to enteric bacteria, an alternative pathway of sulfate reduction via phosphoadenosine 5'-phosphosulfate (PAPS) was proposed. To date, the presence of the corresponding enzyme, PAPS reductase, could be neither confirmed nor excluded in plants. To find possible alternative routes of sulfate assimilation we disrupted the adenosine 5'-phosphosulfate reductase single copy gene in Physcomitrella patens by homologous recombination. This resulted in complete loss of the correct transcript and enzymatic activity. Surprisingly, the knockout plants grew on sulfate as the sole sulfur source, and the concentration of thiols in the knockouts did not differ from the wild type plants. However, when exposed to a sublethal concentration of cadmium, the knockouts were more sensitive than wild type plants. When fed [(35)S]sulfate, the knockouts incorporated (35)S in thiols; the flux through sulfate reduction was approximately 50% lower than in the wild type plants. PAPS reductase activity could not be measured with thioredoxin as reductant, but a cDNA and a gene coding for this enzyme were detected in P. patens. The moss Physcomitrella patens is thus the first plant species wherein PAPS reductase was confirmed on the molecular level and also the first organism wherein both APS- and PAPS-dependent sulfate assimilation co-exist.

Adenosine Phosphosulfate↗
PubMed2004

A multifunctional lipoxygenase with fatty acid hydroperoxide cleaving activity from the moss Physcomitrella patens.

A complex mixture of fatty acid-derived aldehydes, ketones, and alcohols is released upon wounding of the moss Physcomitrella patens. To investigate the formation of these oxylipins at the molecular level we isolated a lipoxygenase from P. patens, which was identified in an EST library by sequence homology to lipoxygenases from plants. Sequence analysis of the cDNA showed that it exhibits a domain structure similar to that of type2 lipoxygenases from plants, harboring an N-terminal import signal for chloroplasts. The recombinant protein was identified as arachidonate 12-lipoxygenase and linoleate 13-lipoxygenase with a preference for arachidonic acid and eicosapentaenoic acid. In contrast to any other lipoxygenase cloned so far, this enzyme exhibited in addition an unusual high hydroperoxidase and also a fatty acid chain-cleaving lyase activity. Because of these unique features the pronounced formation of (2Z)-octen-1-ol, 1-octen-3-ol, the dienal (5Z,8Z,10E)-12-oxo-dodecatrienoic acid and 12-keto eicosatetraenoic acid was observed when arachidonic acid was administered as substrate. 12-Hydroperoxy eicosatetraenoic acid was found to be only a minor product. Moreover, the P. patens LOX has a relaxed substrate tolerance accepting C(18)-C(22) fatty acids giving rise to even more LOX-derived products. In contrast to other lipoxygenases a highly diverse product spectrum is formed by a single enzyme accounting for most of the observed oxylipins produced by the moss. This single enzyme might, in a fast and effective way, be involved in the formation of signal and/or defense molecules thus contributing to the broad resistance of mosses against pathogens.

Amino Acid Sequence↗
PubMed2006

Identification and functional characterization of the moss Physcomitrella patens delta5-desaturase gene involved in arachidonic and eicosapentaenoic acid biosynthesis.

The moss Physcomitrella patens contains high levels of arachidonic acid and lesser amounts of eicosapentaenoic acid. Here we report the identification and characterization of a delta5-desaturase from P. patens that is associated with the synthesis of these fatty acids. A full-length cDNA for this desaturase was identified by data base searches based on homology to sequences of known delta5-desaturase cDNAs from fungal and algal species. The resulting P. patens cDNA encodes a 480-amino acid polypeptide that contains a predicted N-terminal cytochrome b5-like domain as well as three histidine-rich domains. Expression of the enzyme in Saccharomyces cerevisiae resulted in the production of the delta5-containing fatty acid arachidonic acid in cells that were provided di-homo-gamma-linolenic acid. In addition, the expressed enzyme generated delta5-desaturation products with the C20 substrates omega-6 eicosadienoic and omega-3 eicosatrienoic acids, but no products were detected with the C18 fatty acid linoleic and alpha-linolenic acids or with the C22 fatty acid adrenic and docosapentaenoic acids. When the corresponding P. patens genomic sequence was disrupted by replacement through homologous recombination, a dramatic alteration in the fatty acid composition was observed, i.e. an increase in di-homo-gamma-linolenic and eicosatetraenoic acids accompanied by a concomitant disappearance of the delta5-fatty acid arachidonic and eicosapentaenoic acids. In addition, overexpression of the P. patens cDNA in protoplasts isolated from a disrupted line resulted in the restoration of arachidonic acid synthesis.

Arachidonic Acid↗
PubMed2004

A novel aspartic proteinase is targeted to the secretory pathway and to the vacuole in the moss Physcomitrella patens.

In seed plants aspartic proteases (APs) are known to reside in storage vacuoles. Targeting to this compartment is provoked by a secretory signal peptide and the plant-specific insert (PSI). In order to study secretory and vacuolar targeting in a seedless plant, the moss Physcomitrella patens, we isolated a cDNA encoding PpAP1, a novel aspartic proteinase. Sequence alignment with other members of the family of plant APs (EC 3.4.23) revealed a high overall identity and the Pfam motifs for aspartic proteinase and PSI were clearly recognised. In phylogenetic analysis PpAP1 was placed at a very basal position outside of the bigger clusters. Protoplasts transiently expressing the PpAP1 signal peptide fused to GFP showed fluorescence in a well-developed ER-Golgi network. A C-terminal fusion of GFP to the entire PpAP1 protein showed vacuolar fluorescence in transiently transfected protoplasts. Therefore, the vacuole is apparently the in-vivo target for PpAP1. In this study the three-dimensional peculiarity of the endomembrane continuum of ER and Golgi was visualised in a seedless plant for the first time. Above all the functionality of the secretory and the vacuolar targeting signals make them become useful tools for biotechnological approaches.

Amino Acid Sequence↗
PubMed2003

Effects of nutrients, cell density and culture techniques on protoplast regeneration and early protonema development in a moss, Physcomitrella patens.

To regenerate auxotrophic mutants of Physcomitrella patens, two media of increasing complexity were developed. The survival rate of protoplasts was around 30% higher on full medium when compared to standard minimal medium. Protoplast survival was higher in a medium containing 2.5 mmol/L ammonium tartrate compared to a medium with 5 mmol/L of this compound. Solid medium had a positive effect on protoplast survival compared to either liquid medium or solid medium overlaid with cellophane; the maximum survival rate being 31.6%. However, the number of surviving protoplasts without any cell division during the first ten days increased on solid medium. Density and survival rate of protoplasts were positively correlated, but the formation of long protonema filaments decreased markedly. The effect of different protoplast densities could be explained partly by physiologically active compounds excreted into the medium.

Bioreactors↗
PubMed2003

Abscisic acid-induced freezing tolerance in the moss Physcomitrella patens is accompanied by increased expression of stress-related genes.

Abscisic acid (ABA)-induced genes are implicated in the development of freezing tolerance during cold acclimation in higher plants, but their roles in lower land plants have not been determined. We examined ABA- and cold-induced changes in freezing tolerance and gene expression in the moss Physcomitrella patens. Slow equilibrium freezing to -4 degrees C of P. patens protonemata grown under normal growth conditions killed more than 90% of the cells, indicating that the protonema cells are freezing-sensitive. ABA treatment for 24 h dramatically increased the freezing tolerance of the protonemata, while cold treatment only slightly increased the freezing tolerance within the same period. We examined the expressions of fourteen Physcomitrella patens ABA-responsive genes (PPARs), isolated from ABA-treated protonemata. ABA treatment resulted in a remarkable increase in the expression of all the PPAR genes within 24 h. Several of the PPAR genes (PPAR 1 to 8, and 14) were also responsive to cold, but the response was much slower than that to ABA. Treatment with hyperosmotic concentrations of NaCl and mannitol increased freezing tolerance of protonemata and also increased the expression levels of eleven PPAR genes (PPAR2, 3, 5 to 8, and 10 to 14). These results suggest that ABA and environmental stresses positively affect the expression of common genes that participate in protection of protonema cells leading to the development of freezing tolerance.

Abscisic Acid↗