Three new species of arbuscular mycorrhizal fungi (Glomeromycota) and Acaulospora gedanensis revised.

Studies of the morphology and the 45S nuc rDNA phylogeny of three potentially undescribed arbuscular mycorrhizal fungi (phylum Glomeromycota) grown in cultures showed that one of these fungi is a new species of the genus Diversispora in the family Diversisporaceae; the other two fungi are new Scutellospora species in Scutellosporaceae. Diversispora vistulana sp. nov. came from maritime sand dunes of the Vistula Spit in northern Poland, and S. graeca sp. nov. and S. intraundulata sp. nov. originally inhabited the Mediterranean dunes of the Peloponnese Peninsula, Greece. In addition, the morphological description of spores of Acaulospora gedanensis, originally described in 1988, was emended based on newly found specimens, and the so far unknown phylogeny of this species was determined. The phylogenetic analyses of 45S sequences placed this species among Acaulospora species with atypical phenotypic and histochemical features of components of the two inner germinal walls.

Three new species of arbuscular mycorrhizal fungi of the genus Diversispora from maritime dunes of Poland.

Three new species of arbuscular mycorrhizal fungi of the genus Diversispora (phylum Glomeromycota) were described based on their morphology and molecular phylogeny. The phylogeny was inferred from the analyses of the partial 45S rDNA sequences (18S-ITS-28S) and the largest subunit of RNA polymerase II (rpb1) gene. These species were associated in the field with plants colonizing maritime sand dunes of the Baltic Sea in Poland and formed mycorrhiza in single-species cultures.

New Glomeromycotan Taxa, Dominikia glomerocarpica sp. nov. and Epigeocarpum crypticum gen. nov. et sp. nov. From Brazil, and Silvaspora gen. nov. From New Caledonia.

Examination of fungal specimens collected in the Atlantic rain forest ecosystems of Northeast Brazil revealed many potentially new epigeous and semihypogeous glomerocarp-producing species of the phylum Glomeromycota. Among them were two fungi that formed unorganized epigeous glomerocarps with glomoid spores of almost identical morphology. The sole structure that distinguished the two fungi was the laminate layer 2 of their three-layered spore wall, which in spores of the second fungus crushed in PVLG-based mountants contracted and, consequently, transferred into a crown-like structure. Surprisingly, phylogenetic analyses of sequences of the 18S-ITS-28S nuc rDNA and the rpb1 gene indicated that these glomerocarps represent two strongly divergent undescribed species in the family Glomeraceae. The analyses placed the first in the genus Dominikia, and the second in a sister clade to the monospecific generic clade Kamienskia with Kamienskia bistrata. The first species was described here as Dominikia glomerocarpica sp. nov. Because D. glomerocarpica is the first glomerocarp-forming species in Dominikia, the generic description of this genus was emended. The very large phylogenetic distance and the fundamental morphological differences between the second species and K. bistrata suggested us to introduce a new genus, here named as Epigeocarpum gen. nov., and name the new species Epigeocarpum crypticum sp. nov. In addition, our analyses also focused on an arbuscular mycorrhizal fungus originally described as Rhizophagus neocaledonicus, later transferred to the genus Rhizoglomus. The analyses indicated that this species does not belong to any of these two genera but represents a new clade at the rank of genus in the Glomeraceae, here described as Silvaspora gen. nov.

Enzymatic Activity and Its Relationship with Organic Matter Characterization and Ecotoxicity to Aliivibrio fischeri of Soil Samples Exposed to Tetrabutylphosphonium Bromide.

This study aimed to determine the impact of tetrabutylphosphonium bromide [TBP][Br] on the soil environment through an experiment on loamy sand samples. The tested salt was added to soil samples at doses of 0 (control), 1, 10, 100, and 1000 mg kg-1 dry matter (DM). During the experiment, the activity of selected enzymes involved in carbon, phosphorus, and nitrogen cycles, characteristics of organic matter with Fourier-transform infrared (FT-IR) spectroscopy, and toxicity of soil samples in relation to Aliivibrio fischeri were determined at weekly intervals. The results showed that low doses of [TBP][Br] (1 and 10 mg kg-1 DM) did not have much influence on the analyzed parameters. However, the addition of higher doses of the salt into the soil samples (100 and 1000 mg kg-1 DM) resulted in a decrease in the activity of enzymes participating in the carbon and phosphorus cycle and affected the activation of those enzymes involved in the nitrogen cycle. This may be due to changes in aerobic conditions and in the qualitative and quantitative composition of soil microorganisms. It was also observed that the hydrophobicity of soil organic matter was increased. Moreover, the findings suggested that the soil samples containing the highest dose of [TBP][Br] (1000 mg kg-1 DM) can be characterized as acute environmental hazard based on their toxicity to Aliivibrio fischeri bacteria. The increased hydrophobicity and ecotoxicity of the soil samples exposed to the tested salt were also positively correlated with the activity of dehydrogenases, proteases, and nitrate reductase. Observed changes may indicate a disturbance of the soil ecochemical state caused by the presence of [TBP][Br].

Effects of Gellan Oligosaccharide and NaCl Stress on Growth, Photosynthetic Pigments, Mineral Composition, Antioxidant Capacity and Antimicrobial Activity in Red Perilla.

The growing market demand for plant raw materials with improved biological value promotes the extensive search for new elicitors and biostimulants. Gellan gum derivatives may enhance plant growth and development, but have never been used under stress conditions. Perilla (Perilla frutescens, Lamiaceae) is a source of valuable bioproducts for the pharmaceutical, cosmetic, and food industries. However, there is not much information on the use of biostimulators in perilla cultivation. In this work we investigated the effects of oligo-gellan and salt (100 mM NaCl) on the yield and quality of red perilla (P. frutescens var. crispa f. purpurea) leaves. Plants grown under stress showed inhibited growth, smaller biomass, their leaves contained less nitrogen, phosphorus, potassium, total polyphenol and total anthocyanins, and accumulated considerably more sodium than control plants. Treatment with oligo-gellan under non-saline conditions stimulated plant growth and the fresh weight content of the above-ground parts, enhanced the accumulation of nitrogen, potassium, magnesium and total polyphenols, and increased antioxidant activity as assessed by DPPH and ABTS assays. Oligo-gellan applied under saline conditions clearly alleviated the stress effects by limiting the loss of biomass, macronutrients, and total polyphenols. Additionally, plants pretreated with oligo-gellan and then exposed to 100 mM NaCl accumulated less sodium, produced greater amounts of photosynthetic pigments, and had greater antioxidant activity than NaCl-stressed plants. Irrespective of the experimental treatment, 50% extract effectively inhibited growth of Escherichia coli and Staphylococcus aureus. Both microorganisms were the least affected by 25% extract obtained from plants untreated with either NaCl or oligo-gellan. In conclusion, oligo-gellan promoted plant growth and enhanced the quality of red perilla leaves and efficiently alleviated the negative effects of salt stress.

Changes in Photosynthetic Pigments, Total Phenolic Content, and Antioxidant Activity of Salvia coccinea Buc'hoz Ex Etl. Induced by Exogenous Salicylic Acid and Soil Salinity.

Salvia coccinea (Lamiaceae) is a promising source of potential antioxidants, and its extracts can be used in pharmaceutical industry, as well as in food products and cosmetics. Salicylic acid (SA) affects many physiological and metabolic processes in vascular plants under salinity stress. The aim of this study was to investigate the response of S. coccinea to either SA, or sodium chloride (NaCl), or a combination of both. The plants were sprayed with a solution of 0.5 or 1.0 mM SA and watered with 0, 100, 200, or 300 mM NaCl. Exogenous application of SA increased the number of branches, fresh herbal weight, and total chlorophyll content vs control plants. Salinity-exposed plants showed reduced growth, content of photosynthetic pigments total polyphenols, and antioxidant activity. However, foliar application of SA relieved the adverse effects of 100 mM NaCl, as demonstrated by increased number of branches, greater fresh herbal weight, higher content of total chlorophyll, total carotenoids, and total polyphenols, as well as antioxidant potential, detected using ferric-reducing ability of plasma (FRAP) and 2.2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), compared with untreated plants.

Oligo-Alginate with Low Molecular Mass Improves Growth and Physiological Activity of Eucomis autumnalis under Salinity Stress.

Biopolymers have become increasingly popular as biostimulators of plant growth. One of them, oligo-alginate, is a molecule that regulates plant biological processes and may be used in horticultural practice as a plant growth regulator. Biostimulators are mainly used to improve plant tolerance to abiotic stresses, including salinity. The aim of the study was to assess the effects of salinity and oligo-alginate of various molecular masses on the growth and physiological activity of Eucomis autumnalis. The species is an ornamental and medicinal plant that has been used for a long time in the traditional medicine of South Africa. The bulbs of E. autumnalis were coated using depolymerized sodium alginate of molecular mass 32,000; 42,000, and 64,000 g mol-1. All of these oligo-alginates fractions stimulated plant growth, and the effect was the strongest for the fraction of 32,000 g mol-1. This fraction was then selected for the second stage of the study, when plants were exposed to salt stress evoked by the presence of 100 mM NaCl. We found that the oligo-alginate coating mitigated the negative effects of salinity. Plants treated with the oligomer and watered with NaCl showed smaller reduction in the weight of the above-ground parts and bulbs, pigment content and antioxidant activity as compared with those not treated with the oligo-alginate. The study demonstrated for the first time that low molecular mass oligo-alginate may be used as plant biostimulator that limits negative effects of salinity in E. autumnalis.