Exogenous calcium modulates the activity of adenylate cyclases in potato plants under biotic stress

Abstract: This article aims to study the influence of different concentrations of calcium ions on the activity of transmembrane (tmAC) and soluble forms of adenylyl cyclase (sAC) in the cells of roots and stems of the plants of two types of potatoes. It compares and contrasts their stability to the agent of the annular rot Clavibacter michiganensis ssp. Sepedonicus (Cms) when exposed to its exopolysaccharides. The experimental results have shown that the reaction of tmAC from the roots and stems to exogenous Ca2+ was almost opposite in the plants of both types. In the root cells of the plants of the resistant types, 1 and 10 mM of Ca2+ have activated tmAC in a very intensive way. In the stem, the average concentrations of Ca2+ inhibited the tmAC activity, while the highest, 1 and 10 mM, did not affect it. the activity of tmAC taken from the root cells of the receptive type of plants was not activated significantly by the increased concentrations of Ca2+, whereas, in the stems, all the concentrations of Ca2+, tmAC activity increased substantially starting with 1 μM. Thus, the unequal reaction of adenylate cyclases of the potato plants of both types to different concentrations of exogenous calcium, testifies, most likely, the presence of several isoform of this ferment that differ in the sensitivity to calcium ions. At the same time, it is possible that the plants of both types may also differ in the spectrum of such isoforms. Since the influence of Cms exopolysaccharides significantly changes the sensitivity to the calcium ions of both forms of adenylate cyclases in the cells of plants of both types, it can be assumed that this feature is one of the mechanisms of these plants’ resistance to the pathogen.