An atypical N-ethylmaleimide sensitive factor enables the viability of nematode-resistant Rhg1 soybeans.
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ABSTRACT: N-ethylmaleimide sensitive factor (NSF) and ?-soluble NSF attachment protein (?-SNAP) are essential eukaryotic housekeeping proteins that cooperatively function to sustain vesicular trafficking. The "resistance to Heterodera glycines 1" (Rhg1) locus of soybean (Glycine max) confers resistance to soybean cyst nematode, a highly damaging soybean pest. Rhg1 loci encode repeat copies of atypical ?-SNAP proteins that are defective in promoting NSF function and are cytotoxic in certain contexts. Here, we discovered an unusual NSF allele (Rhg1-associated NSF on chromosome 07; NSFRAN07 ) in Rhg1+ germplasm. NSFRAN07 protein modeling to mammalian NSF/?-SNAP complex structures indicated that at least three of the five NSFRAN07 polymorphisms reside adjacent to the ?-SNAP binding interface. NSFRAN07 exhibited stronger in vitro binding with Rhg1 resistance-type ?-SNAPs. NSFRAN07 coexpression in planta was more protective against Rhg1 ?-SNAP cytotoxicity, relative to WT NSFCh07 Investigation of a previously reported segregation distortion between chromosome 18 Rhg1 and a chromosome 07 interval now known to contain the Glyma.07G195900 NSF gene revealed 100% coinheritance of the NSFRAN07 allele with disease resistance Rhg1 alleles, across 855 soybean accessions and in all examined Rhg1+ progeny from biparental crosses. Additionally, we show that some Rhg1-mediated resistance is associated with depletion of WT ?-SNAP abundance via selective loss of WT ?-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 Rhg1-related resistance in plants will require a compatible NSF partner for the resistance-conferring ?-SNAP.
SUBMITTER: Bayless AM
PROVIDER: S-EPMC5948960 | biostudies-literature | 2018 May
REPOSITORIES: biostudies-literature
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