To elucidate the functional role of the small signaling peptide RALF34 in the parental root meristem and its role in lateral root initiation, we studied changes in Cucumis sativus proteome during CsRALF34 gene overexpression. Composite plants with transgenic root systems carrying the construct for CsRALF34 overexpression (p35S::CsRALF34-TermAct) and control roots carrying p35S-GUS-TermAct were obtained and their proteome profiles were compared.