Cyclic nucleotide-gated channel involved in the establishment of both rhizobial and mycorrhizal associations (PubMed:27230377). Required for full activation of nuclear-localized Ca(2+) oscillations by Nod and Myc factors (PubMed:27230377). Simultaneous activation of the K(+)-permeable channel DMI1 and the Ca(2+) channel CNGC15 can give rise to sustained Ca(2+) oscillations (PubMed:27230377). May function during fertilization in both female and male gametophytic Ca(2+) signaling (PubMed:27230377). Interacts (via N-terminus) with DMI1 (via c-terminus). The Nod factor has no effect on this interaction, implying that the complex is maintained after activation. Expressed in roots, stems, leaves, flowers and pods. Belongs to the cyclic nucleotide-gated cation channel (TC 1.A.1.5) family.