Influence of Bacterial Mutualists and Phytopatogenes on Changes in Concentrations of cAMP and H<sub>2</sub>O<sub>2</sub> in Pea Seedles of Rondo Varieties and its Clutterless and Superclub Mutants

Changes in the concentrations of hydrogen peroxide and cyclic adenosine monophosphate (cAMP) in the roots of seedlings of pea cv. Rondo and its supernodulating mutant Nod3 and anodulating K14 were studied during infection with Rhizobium leguminosarum bv. vicea (strain RCAM 1022) or Pseudomonas syringae pv. pisi (strain 1845). It was shown that 360 min after infection of pea seedlings of the Rondo variety, the level of endogenous hydrogen peroxide slightly differed from the control. In the roots of Nod3 seedlings, this level significantly decreased, and in the roots of K14 it significantly increased when infected with the 1845 strain, but remained unchanged when exposed to bacteria of the RCAM 1022 strain. and young root hairs of Rondo seedlings, while strain 1845 had no effect on this parameter. Both types of bacteria had no effect on the concentration of cAMP in the roots of seedlings of the Nod3 mutant, whereas in K14, under the influence of RCAM 1022, the cAMP level almost doubled, and under the influence of 1845, it decreased. It is assumed that hydrogen peroxide and cAMP may be involved in the formation of supernodulating and nodulating phenotypes of mutants, as well as in the formation of resistance to a specific pathogen, Pseudomonas syringae pv. pisi. It is possible that this phenomenon can be used to diagnose the resistance of newly created mutants and pea varieties to the blight pathogen.