Salicylate-Induced Changes of Protein Secretion into Apoplast in Pea Roots Is Not Always Associated with Increased Expression of Genes Encoding Them

This work presents the results of the analysis of the effect of the phytohormone salicylic acid on the secretion of proteins to the apoplast of the pea seedlings roots. It is shown that the secretion of a number of defense proteins (β-1,3-glucanase, acid and alkaline endochitinases, disease resistance response protein, and protease inhibitors) is increased, but there is no activation of the expression of the genes encoding these proteins. A distinctive feature of the pea root response to the salicylic acid was the activation of the expression of the genes encoding isoforms of chitinase-like proteins and the secretion of these proteins into the apoplast.