An atypical N-ethylmaleimide sensitive factor enables the viability of nematode-resistant soybeans.

N-ethylmaleimide sensitive factor (NSF) and α-soluble NSF attachment protein (α-SNAP) are essential eukaryotic housekeeping proteins that cooperatively function to sustain vesicular trafficking. The "resistance to 1" () locus of soybean () confers resistance to soybean cyst nematode, a highly damaging soybean pest. loci encode repeat copies of atypical α-SNAP proteins that are defective in promoting NSF function and are cytotoxic in certain contexts. Here, we discovered an unusual allele (-associated NSF on chromosome 07; ) in germplasm. NSF protein modeling to mammalian NSF/α-SNAP complex structures indicated that at least three of the five NSF polymorphisms reside adjacent to the α-SNAP binding interface. NSF exhibited stronger in vitro binding with resistance-type α-SNAPs. NSF coexpression was more protective against α-SNAP cytotoxicity, relative to WT NSF Investigation of a previously reported segregation distortion between chromosome 18 and a chromosome 07 interval now known to contain the NSF gene revealed 100% coinheritance of the allele with disease resistance alleles, across 855 soybean accessions and in all examined progeny from biparental crosses. Additionally, we show that some -mediated resistance is associated with depletion of WT α-SNAP abundance via selective loss of WT α-SNAP loci. Hence atypical coevolution of the soybean SNARE-recycling machinery has balanced the acquisition of an otherwise disruptive housekeeping protein, enabling a valuable disease resistance trait. Our findings further indicate that successful engineering of -related resistance in plants will require a compatible NSF partner for the resistance-conferring α-SNAP.