Endophytic bacteria are an important part of different functions in plants that lead to plants’ production characteristics as well as their stress response mechanisms. Endophytic bacterial diversity was analyzed in this study to describe 16S rRNA variability and changes in the leaves of drought-tolerant and drought-susceptible wheat when growth under in vitro conditions. A metagenomic analysis was applied and a pilot exploratory study was performed to prove this type of analysis as applicable to tracking endophytic bacterial diversity changes when a drought stress is applied to an in vitro culture of wheat. The study showed that the changes in the bacterial endophytes’ variabilities associated preferentially with the drought stress varietal characteristics of the analyzed wheat instead of the applied stress conditions.

Oyster mushroom (Pleurotus ostreatus) is still one of the most cultivated edible and medicinal mushrooms. Despite its frequent cultivation around the world, there is currently just a little information available on the variability of strains in terms of the content of β-glucans in them. This work presents an extensive study of 60 strains in terms of the content of α-glucans and β-glucans in their caps and stipes. The authenticity of the production strains based on an analysis of the variability of their genome by CDDP (Conserved DNA-derived polymorphism) markers was confirmed, whereas identical CDDP profiles were identified between samples 45, 89, 95, and 96. Genetic variability of the analyzed production strains showed a high polymorphism and effective discriminative power of the used marking technique. Medium positive correlations were found among the CDDP profiles and β-glucan content in the group of strains that generated the same CDDP profiles, and low negative correlation was found among these profiles in the group of low β-glucan content strains. For the determination of glucans content, Mushroom and Yeast analytical enzymatic kit (Megazyme, Bray, Co. Wicklow, Ireland) were used. The results clearly showed that the stipe contains on average 33% more β-glucans than the cap. The minimum detected β-glucan content in the stipe was in strain no. 72, specifically 22%, and the maximum in strain no. 43, specifically 56%, which after the conversion represents a difference of 155%. From the point of view of β-glucan content, the stated strain no. 43 appears to be very suitable for the commercial production of β-glucans under certain conditions.

A plant microbiome is an important factor in plant growth, stress resistance, health status, and consumer quality and safety. The rhizosphere microbiome evolves in a negotiation between microbial communities that inhabit soil and plant root tissue. In this study, the rhizosphere and root internal tissue microbiome of six varieties of lettuce were analyzed in normal conditions and under salinity stress. The metabarcoding analysis used 16S rRNA gene and ITS2 region sequencing. The microbiomes of root samples were significantly less diverse with different members of the community compared to those of the rhizosphere. A significant effect of lettuce variety was found on the diversity index for bacteria and fungi. Varieties formed very different communities of bacteria in roots. Pseudomonas, Herbaspirillum, Mycobacterium, potentially pathogenic Enterobacter, and other genera were more prevalent in certain varieties. Salinity stress had a significant negative impact on bacterial diversity and community composition, whereas the diversity of fungi has not changed significantly, and the fungal community has changed less than the bacterial one. Changes were more evident in varieties that were more resistant to salinity stress than in sensitive varieties.

The aim of this study was to compare the natural variability of the expression of class I chitinase gene in grapes of Vitis vinifera L. varieties as well as investigate their antimicrobial activity. Further, the effect of antimicrobial activity in chitinase expression was analyzed. Matured berries of thirteen grape varieties were used in the study—Alibernet, Dornfelder, Cabernet Sauvignon, Blaufränkisch, Sauvignon Blanc, Welschriesling, Weisser Riesling, Irsai Oliver, Pinot Blanc, Pálava, Müller-Thurgau, Grűner Veltliner, and Feteasca Regala, grown in the Small Carpathians wine region of Slovakia, Vrbové. Chitinase I gene expression was found to be similar in most of the analyzed varieties with the except of two varieties, where the expression of chitinase I was significantly higher—Pinot Blanc and Savignon Blanc. By comparing the varieties between the lowest and highest expression fold change, they were statistically different in the level of its chitinase I gene expression. Grape pomace extracts of analyzed Vitis vinifera L. were effective against Gram-positive, Gram-negative bacteria and yeasts, but a weak correlation tendency was found between chitinase I gene expression and antimicrobial activity, only against Staphylococcus aureus subsp. aureus, Candida albicans, and Candida glabrata.

The significant healing effect of Tilia platyphyllos Scop. and Tilia cordata Mill. flowers are well known. However, the flowers of Tilia tomentosa Moench. are not suitable for harvest due to their toxic effects. To investigate the diverse background of this effect, we applied a functional miRNA-based marker, mannose expression analysis and determined the content of bioactive compounds. Out of nine tested markers, three (miR160, miR167 and miR408) provided reproducible miRNA-based loci and two of them (miR160 and miR398) enabled the acquisition of fingerprinting specific to flower and leaf samples of T. platyphyllos and T. tomentosa. The most pronounced profiling was specific for miR408 marker, the function of which is connected to plant defense and adaptation mechanisms. We confirmed the suitability of microRNA-based markers for polymorphism determination of flowers of selected species of lime-tree. The highest values of antioxidant activity, flavonoids, total polyphenols and phenolic acids content have been reached in silver linden flowers. When comparing the transcription activity of mannose in flowers, more than 30 times higher levels of mannose transcripts for the silver linden flowers was observed.