Bacterial endophytes are a class of endosymbiotic microorganisms widespread among plants that colonize intercellular and intracellular spaces of all plant compartments and do not cause plant disease or significant morphological changes. Plant and endophytic bacteria association includes vast diversity of bacterial taxa and plant hosts and in this review we present an overview of taxonomic composition of endophytes identified in common agricultural crops. Further, during the last decade, new aspects of the microbial diversity have emerged with application of new metagenomic analysis methods in studies of bacterial endophytes. Endophytic bacteria community structure is influenced by plant genotype, abiotic and biotic factors such as environment conditions, microbe -microbe interactions and plant -microbe interactions. Agricultural practices, such as soil tillage, irrigation, use of pesticides and fertilizers have a major effect on function and structure of soil and endophytic microbial populations. Therefore, the use of agricultural practices that maintain natural diversity of plant endophytic bacteria is becoming an important element of sustainable agriculture that could ensure plant productivity and quality of agricultural production. The diverse endophytic microbial communities play integral and unique role in the functioning of agroecosystems. Endophytic bacteria have been shown to have several beneficial effects on their host plant, including growth promoting activity, modulation of plant metabolism and phytohormone signalling that leads to adaptation to environmental abiotic or biotic stress. Use of endophytic bacteria presents a special interest for development of agricultural applications that ensure improved crop performance under cold, draught or contaminated soil stress conditions or enhanced disease resistance.

In vitro conditions for Japanese quince polyploidisation were investigated. Microshoots and isolated cotyledons were treated with colchicine and oryzalin. Morphogenesis was more dependent on the concentration of colchicine or oryzalin than on the duration of exposure, genotype differences were observed. Low oryzalin concentrations had no impact on morphogenesis. Plants with changed chromosome numbers were obtained at 0.25-38 mM colchicine and 10-50 lM oryzalin concentrations. It was determined that stomata length is a suitable parameter for identifying putative Japanese quince tetraploids. Stomata of tetraploid shoots of the same clone were approximately 1/3 longer than in the diploids. It was shown that through polyploidisation gigas effect was not obtained in fruit size but tetraploids have reduced seed set and an increased proportion of fruit flesh.

In this study, a protocol is described for rapid preparation of an enriched, reasonably pure fraction of nuclear proteins from the leaves of tobacco (Nicotiana tabacum), potato (Solanum tuberosum) and apple (Malus domestica). The protocol gives reproducible results and can be carried out quickly in 2 hours. Tissue extracts clarified with filtration were treated with non-ionic detergent (Triton X-100) to lyse membranes of contaminating organelles. Nuclei were collected from a 60% Percoll layer of density gradient following low-speed centrifugation. Western blot analysis using antibodies to marker proteins of organelles indicated that the nuclear protein fractions were highly enriched and free or nearly free of proteins from the endoplasmic reticulum and chloroplasts.

Anthocyanins are essential contributors to fruit coloration, an important quality feature and a breed determining trait of a sweet cherry fruit. It is well established that the biosynthesis of anthocyanins is regulated by an interplay of specific transcription factors belonging to MYB and bHLH families accompanied by a WD40 protein. In this study, we isolated and analyzed PaWD40, PabHLH3, PabHLH33, and several closely related MYB10 gene variants from different cultivars of sweet cherry, analyzed their expression in fruits with different anthocyanin levels at several developmental stages, and determined their capabilities to modulate anthocyanin synthesis in leaves of two Nicotiana species. Our results indicate that transcription level of variant PaMYB10.1-1 correlates with fruit coloration, but anthocyanin synthesis in Nicotiana was induced by another variant, PaMYB10.1-3, which is moderately expressed in fruits. The analysis of two fruit-expressed bHLH genes revealed that PabHLH3 enhances MYB-induced anthocyanin synthesis, whereas PabHLH33 has strong inhibitory properties.

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Anthocyanins are biologically active water-soluble plant pigments that are responsible for blue, purple, and red colors in various plant parts—especially in fruits and blooms. Anthocyanins have attracted attention as natural food colorants to be used in yogurts, juices, marmalades, and bakery products. Numerous studies have also indicated the beneficial health effects of anthocyanins and their metabolites on human or animal organisms, including free-radical scavenging and antioxidant activity. Thus, our aim was to review the current knowledge about anthocyanin occurrence in plants, their stability during processing, and also the bioavailability and protective effects related to the antioxidant activity of anthocyanins in human and animal brains, hearts, livers, and kidneys.

Interactions between host plants and endophytic microorganisms play an important role in plant responses to pathogens and environmental stresses and have potential applications for plant stress management under in vitro conditions. We assessed the effect of endophytic bacteria on the growth and proliferation of domestic apple cv. Gala shoots in vitro. Further, a model apple cell suspension system was used to examine molecular events and protein expression patterns at an early stage of plant–endophyte interaction. Among the seven strains used in the study, Bacillus spp. strains Da_1, Da_4, and Da_5 and the Pseudomonas fluorescens strain Ga_1 promoted shoot growth and auxiliary shoot proliferation. In contrast, Bacillus sp. strain Oa_4, P. fluorescens strain Ga_3 and P. orientalis strain G_12 inhibited shoot development. In the cell suspension, the effects of the association between endophytic bacteria and plant cells were specific to each strain. Modulation of the cellular redox balance was monitored in the apple cells using a 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) probe, and strain-specific effects were observed that correlated with the in vitro shoot development results. Proteomic analysis revealed differences in protein expressions in apple cells co-cultivated with different Bacillus spp. strains that had contrasting effects on cellular redox balance and shoot development. The Bacillus sp. strain Da_4, which enhanced shoot development and oxidation of H2DCFDA, induced differential expression of proteins that are mainly involved in the defense response and regulation of oxidative stress. Meanwhile, treatment with Bacillus sp. strain Oa_4 led to strong upregulation of PLAT1, HSC70-1 and several other proteins involved in protein metabolism and cell development. Taken together, the results suggest that different cell signaling and response events at the early stage of the plant–endophyte interaction may be important for strain-dependent regulation of cellular redox balance and development of shoot phenotype.

Bacterial endophytes are common inhabitants of plant tissues that have been shown to play an important role in regulation of plant growth and to have the potential as biological agent for plant disease protection. Only fragmented knowledge is present about endophytes that reside in the phyllosphere of cultivated tree plants such as domestic apple (Malus × domestica Borkh.). Therefore the goal of this study was to identify culturable endophytic bacteria characteristic of an apple phyllosphere and to establish biochemical traits involved in plant growth promoting activity as well as to study microbial growth suppressing activity of the endophytes. Thirty-eight putative endophytic bacteria were isolated from apple buds of cultivars 'Gala', 'Golden Delicious' and 'Orlovim' grown under field conditions and 13 of the isolates were assigned to Curtobacterium, Pantoea and Pseudomonas species. Biochemical tests revealed traits important for plant growth stimulation and microbial growth suppression characteristics of the isolates, including nitrogen fixation, production of indole-3-acetic acid (IAA), phosphate solubilization, production of siderophores and hydrogen cyanide. Several isolates displayed antagonistic activity against selected non-pathogenic and pathogenic bacterial strains: 17 isolates were able to inhibit growth of Micrococcus luteus, 4 -Pseudomonas aeruginosa, 2 -Escherichia coli and Bacillus subtilis. In addition, it was determined that two isolates of Pantoea sp. (D_8 and D_10) and Pseudomonas fluorescens group isolate D_7 were able to inhibit growth of the apple scab pathogen (Venturia inaequalis (Cke) Wint.), suggesting a role of the endophytes in disease resistance and a potential use for biocontrol applications.