The heterologous expression of a Glycine max homolog of NONEXPRESSOR OF PR1 (NPR1) and α-hydroxynitrile glucosidase suppresses parasitism by the root pathogen Meloidogyne incognita in Gossypium hirsutum

Experiments in Glycine max (soybean) identified the expression of the salicylic acid signaling and defense gene NONEXPRESSOR OF PR1 (NPR1) in root cells (i.e., syncytium) parasitized by the plant parasitic nematode Heterodera glycines undergoing the process of resistance. Gm-NPR1-2 overexpression in G. max effectively suppresses parasitism by H. glycines. The heterologous expression of Gm-NPR1-2 in Gossypium hirsutum impairs the ability of the parasitic nematode Meloidogyne incognita to form root galls, egg sacs, eggs and second-stage juvenile (J2) nematodes. In related experiments, a G. max β-glycosidase (Gm-βg-4) related to Lotus japonicus secreted defense gene α-hydroxynitrile glucosidase LjBGD7 suppresses M. incognita parasitism. The results identify a cumulative negative effect that the transgenes have on M. incognita parasitism and demonstrate that the G. max–H. glycines pathosystem is a useful tool to identify defense genes that function in other agriculturally relevant plant species to plant parasitic nematodes with different strategies of parasitism.