The soybean GmSNAP18 gene underlies two types of resistance to soybean cyst nematode

Shiming Liu,Jingwen Kang,Naoufal Lakhssassi,Vincent Colantonio,Sadia Bekal,Robert Heinz,Bjorn Rotter,Pramod K Kandoth,Khalid Meksem,Johannes Dapprich,Zhou Zhou,Silvia Cianzio,Greg Yeckel,Melissa G Mitchum

doi:10.1038/ncomms14822

Abstract

Two types of resistant soybean (Glycine max (L.) Merr.) sources are widely used against soybean cyst nematode (SCN, Heterodera glycines Ichinohe). These include Peking-type soybean, whose resistance requires both the rhg1-a and Rhg4 alleles, and PI 88788-type soybean, whose resistance requires only the rhg1-b allele. Multiple copy number of PI 88788-type GmSNAP18, GmAAT, and GmWI12 in one genomic segment simultaneously contribute to rhg1-b resistance. Using an integrated set of genetic and genomic approaches, we demonstrate that the rhg1-a Peking-type GmSNAP18 is sufficient for resistance to SCN in combination with Rhg4. The two SNAPs (soluble NSF attachment proteins) differ by only five amino acids. Our findings suggest that Peking-type GmSNAP18 is performing a different role in SCN resistance than PI 88788-type GmSNAP18. As such, this is an example of a pathogen resistance gene that has evolved to underlie two types of resistance, yet ensure the same function within a single plant species.

Highlights

Two types of resistant soybean (Glycine max (L.) Merr.) sources are widely used against soybean cyst nematode (SCN, Heterodera glycines Ichinohe)
We identified a total of 222 recombinant lines with chromosomal breakpoints around the rhg1-a locus, of which three recombinants (ExF4361, ExF3126 and WxF6034) were crucial in defining the interval carrying the rhg1-a or rhg1-s gene
Three genes were identified within the 14.3 kb interval; one codes for an armadillo/b-catenin-like repeat (Glyma18g02570) at the interval carrying marker 570; the second is an amino acid transporter (AAT, Glyma18g02580) at the interval carrying marker 580; the third is a soluble N-ethylmelaimide sensitive factor (NSF) attachment protein (GmSNAP18, Glyma18g02590) at the interval carrying marker 590

Summary

Introduction

Two types of resistant soybean (Glycine max (L.) Merr.) sources are widely used against soybean cyst nematode (SCN, Heterodera glycines Ichinohe). QTL on chromosomes 18 (rhg1) and 8 (Rhg4) are the two major resistance QTL that have been consistently mapped and reported in a variety of soybean germplasm In some accessions, such as plant introduction (PI) 88788, rhg[1] is sufficient to provide resistance against the nematode with the gene itself displaying incomplete dominance[2]. In other cases, such as the soybean cultivar (cv.) Forrest, resistance to SCN requires both rhg[1] and Rhg[4] The complementation analyses showed the Forrest GmSNAP18 is required for Peking-type resistance, as the resistant GmSNAP18 allele of PI 88788 or the susceptible rhg1-s could not restore resistance in the Forrest (Peking-type) Rhg[4] background

Methods

Results

Conclusion