Modulation of Stress Protein Gene Expression in Potato Tissues In Vitro under the Influence of Chalcogen and Metal Nanocomposites during the Infection with Pectobacterium carotovorum

Pathogenesis-related (PR) proteins represent one of the mechanisms of plant defense under biotic stress. When a plant interacts with a pathogen, PR proteins amount increases, serving as the plant’s first line of defense. PR proteins possess a broad spectrum of enzymatic activity, and can reduce the negative effects caused by phytopathogens. In this study, we investigated the effect of nanocomposites (NCs)—substances consisting of nanoparticles (NPs) of Se or Mn chemically immersed into a polymer matrix of the natural polysaccharide arabinogalactan (AG)—on the PR genes expression in the in vitro grown potato plants infected with the phytopathogen Pectobacterium carotovorum (Pc). It was found that the POX, PR1, PR2, PR3, PR-5-18, PR6, PR9, and PR10 genes are induced twice and more in response to the Pc infection. Treatment of healthy plants with Se/AG NC induced the expression of PR3 and POX and suppressed the expression of the PR6 and PR9 genes. Treatment with Mn/AG NC increased the expression of the PR6 gene and decreased the expression of the PR9 gene. When Pc-infected potato plants were exposed to the NCs, a decrease in the expression of the following genes was noted: Se/AG NC—PR3 and PR6, Mn/AG NC—PR1, PR6, and PR9. Increased expression of the PR3 and PR9 genes was noted in the infected plants under the influence of Mn/AG NC. Thus, the NCs are capable to influence the expression of the potato PR genes.