Secreted venom allergen-like proteins of plant-parasitic nematodes modulate host defence responses in plants

Recently, we showed that the secreted venom allergen-like protein of the potato cyst nematode Globodera rostochiensis Gr-VAP1 physically interacts with the apoplastic cysteinepapain-like proteases Rcr3pim of Solanum pimpinellifolium. In the presence of the extracellular immune receptor Cf-2 in tomato plants this interaction between Gr-VAP1 and Rcr3pim activates a defence-related programmed cell death and resistance to nematodes. Thus, Gr-VAP1 is able to trigger defence responses in a host plant of G. rostochiensis, but the virulence function of this venom allergen-like protein in nematode parasitism is not known. A specific knockdown of Gr-VAP1 expression in G. rostochiensis by RNA interference revealed that its product promotes virulence of infective juveniles. The heterologous expression of diverse homologous venom allergen-like proteins from cyst nematodes in transgenic Arabidopsis thaliana plants altered their ability to mount an immune response to cyst nematodes, multiple fungal plant pathogens, and the immunogenic peptide flg22. Global gene expression analysis of these transgenic plants has shed light on the molecular mechanisms underlying the modulation of plant innate immunity by venom allergen-like proteins of plant-parasitic nematodes.