The utility of polymorphism analysis was determined for differentiation of the following subspecies of the Gram-positive plant pathogenic bacterium, Clavibacter michiganensis: C. m. subsp. michiganensis, C. m. subsp. sepedonicus, C. m. subsp. insidiosus C. m. subsp. nebraskensis, and C. m. subsp. tessellarius. Specific primers designed for amplification of the housekeeping genes recA, rpoB, and rpoD generated 827-, 1037-, and 862-bp DNA fragments, respectively. PCR products obtained from 40 C. michiganensis strains were analysed using RFLP with four restriction endonucleases, and those PCR products with specific RFLP patterns were sequenced. The genotypes discriminated after PCR-RFLP were specific for each subspecies and also allowed for differentiation of C. m. subsp. michiganensis strains. Sequence analysis of the recA, rpoB, and rpoD gene fragments also distinguished C. michiganensis subspecies and was useful for phylogenetic analysis of all subspecies. For rapid, inexpensive, and effective differentiation of the five subspecies in this research, we recommend the amplification of recA and/or rpoD gene fragments and digestion of the PCR products with the restriction endonuclease FnuDII.

Glutathione is a metabolite that plays an important role in plant response to biotic stress through its ability to remove reactive oxygen species, thereby limiting the degree of potential oxidative damage. It can couple changes in the intracellular redox state to the development, especially the defense responses, of plants. Several studies have focused on measuring glutathione levels in virus infected plants, but have not provided complete information. Therefore, we analyzed, for the first time, the content of glutathione as well as its ultrastructural distribution related to susceptible and hypersensitive potato–Potato virus Y NTN (PVYNTN) interaction, with an aim of providing new insight into interactive responses to PVYNTN stress. Our findings reported that the inoculation of PVYNTN caused a dynamic increase in the content of glutathione, not only in resistance but also in susceptible reaction, especially at the first steps of plant–virus interaction. Moreover, the increase in hypersensitive response was much more dynamic, and accompanied by a significant reduction in the content of PVYNTN. By contrast, in susceptible potato Irys, the content of glutathione decreased between 7 and 21 days after virus inoculation, which led to a significant increase in PVYNTN concentration. Additionally, our findings clearly indicated the steady induction of two selected potato glutathione S-transferase StGSTF1 and StGSTF2 genes after PVYNTN inoculation, regardless of the interaction type. However, the relative expression level of StGSTF1 did not significantly differ between resistant and susceptible plants, whereas the relative expression levels of StGSTF2 differed between susceptible and resistant reactions. Therefore, we proposed that StGSTF2 can act as a marker of the type of response to PVYNTN. Our observations indicated that glutathione is an important component of signaling as well as the regulatory network in the PVYNTN–potato pathosystem. In resistance responses to PVYNTN, this metabolite activates plant defenses by reducing potential damage to the host plant cell, causing a reduction in virus concentration, while it can also be involved in the development of PVYNTN elicited symptoms, as well as limiting oxidative stress, leading to systemic infection in susceptible potato plants.

The concentrations of the bioactive compounds in potato tubers are determined by both genetic potential and environmental factors. The purpose of the experiment was to determine the influence of organic and integrated production on the expression of the genetic potential with respect to the antioxidant properties of potato tubers and to evaluate its stability under different environmental conditions. This phenotyping was performed on seven new breeding lines (tetraploid clones) and three modern cultivars: Jelly, Satina and Tajfun. The results indicated that production system and location significantly influenced the antioxidant capacity measured by FRAP method. Organic farming and the location Chwałowice were characterized by higher values. Furthermore, anitioxidative capacity measured by FRAP method was correlated with chlorogenic acid content (r = 0.590**) and glutathione fractions, especially with the reduced form (GSH, r = 0.692**). Multidimensional comparative analysis (MCA) proved a better development of antioxidant properties of potato tubers in the organic cultivation system when compared with the integrated. Especially favorable were growing conditions at Boguchwała (organic) and worst at Młochów (integrated). From all investigated varieties, the best antioxidant properties were found in ‘Satina’ and ‘Jelly’. Clones TG-97-403 and 13-VIII-45 developed the weakest health promoting traits.

The aim of this study was to determine the effect of gold and silver nanoparticles on the activity of antioxidant enzymes (ascorbate peroxidase (APX), superoxide dismutase (SOD), guaiacol peroxidase (POX), and catalase (CAT)), the free radical scavenging capacity, and the total polyphenol capacity of lavender (Lavandula angustifolia Mill.) cultivar “Munstead” propagated in vitro. In the experiment, fragments of lavender plants were cultivated in vitro on medium with the addition of 1, 2, 5, 10, 20, and 50 mg∙dm−3 of AgNPs or AuNPs (particle sizes 24.2 ± 2.4 and 27.5 ± 4.8 nm, respectively). It was found that the nanoparticles increase the activity of the antioxidant enzymes APX and SOD; however, the reaction depends on the NP concentration. The highest APX activity is found in plants propagated on media with 2 and 5 mg∙dm−3 of AgNPs. AuNPs significantly increase the APX activity when added to media with a concentration of 10 mg∙dm−3. The highest SOD activity is recorded at 2 and 5 mg∙dm−3 AgNP and AuNP concentrations. The addition of higher concentrations of nanoparticles to culture media results in a decrease in the APX and SOD activity. The addition of AuNPs to culture media at concentrations from 2 to 50 mg∙dm−3 increases the POX activity in comparison to its activity when AgNPs are added to the culture media. No significant influence of NPs on the increase in CAT activity was demonstrated. AgNPs and AuNPs increased the free radical scavenging capacity (ABTS•+). The addition of NPs at concentrations of 2 and 5 mg∙dm−3 increased the production of polyphenols; however, in lower concentrations it decreased their content in lavender tissues.

The aim of this study was to determine how the addition of gold and silver nanoparticles to culture media affects the composition of essential oils extracted from Lavandula angustifolia propagated on MS media with the addition of 10 and 50 mg·dm−3 of gold (24.2 ± 2.4 nm) and silver (27.5 ± 4.8 nm) nanocolloids. The oil extracted from the lavender tissues propagated on the medium with 10 mg·dm−3 AgNPs (silver nanoparticles) differed the most with respect to the control; oil-10 compounds were not found at all, and 13 others were detected which were not present in the control oil. The addition of AuNPs (gold nanoparticles) and AgNPs to the media resulted in a decrease of lower molecular weight compounds (e.g., α- and β-pinene, camphene, δ-3-carene, p-cymene, 1,8-cineole, trans-pinocarveol, camphoriborneol), which were replaced by those of a higher molecular weight (τ- and α-cadinol 9-cedranone, cadalene, α-bisabolol, cis-14-nor-muurol-5-en-4-one, (E,E)-farnesol).