title: A SNARE-Like Protein and Biotin Are Implicated in Soybean Cyst Nematode Virulence.
abstract: Phytoparasitic nematodes that are able to infect and reproduce on plants that are considered resistant are referred to as virulent. The mechanism(s) that virulent nematodes employ to evade or suppress host plant defenses are not well understood. Here we report the use of a genetic strategy (allelic imbalance analysis) to associate single nucleotide polymorphisms (SNPs) with nematode virulence genes in Heterodera glycines, the soybean cyst nematode (SCN). To accomplish this analysis, a custom SCN SNP array was developed and used to genotype SCN F3-derived populations grown on resistant and susceptible soybean plants. Three SNPs reproducibly showed allele imbalances between nematodes grown on resistant and susceptible plants. Two candidate SCN virulence genes that were tightly linked to the SNPs were identified. One SCN gene encoded biotin synthase (HgBioB), and the other encoded a bacterial-like protein containing a putative SNARE domain (HgSLP-1). The two genes mapped to two different linkage groups. HgBioB contained sequence polymorphisms between avirulent and virulent nematodes. However, the gene encoding HgSLP-1 had reduced copy number in virulent nematode populations and appears to produce multiple forms of the protein via intron retention and alternative splicing. We show that HgSLP-1 is an esophageal-gland protein that is secreted by the nematode during plant parasitism. Furthermore, in bacterial co-expression experiments, HgSLP-1 co-purified with the SCN resistance protein Rhg1 α-SNAP, suggesting that these two proteins physically interact. Collectively our data suggest that multiple SCN genes are involved in SCN virulence, and that HgSLP-1 may function as an avirulence protein and when absent it helps SCN evade host defenses.
authors.affiliation: Department of Plant, Soil and Agricultural Systems, 1205 Lincoln Dr. Southern Illinois University, Carbondale, IL, 62901, United States of America.
authors.forename: Sadia
authors.initials: S
authors.lastname: Bekal
authors.affiliation: Department of Crop Sciences, University of Illinois, 1102 South Goodwin Ave. Urbana, IL, 61801, United States of America.
authors.forename: Leslie L
authors.initials: LL
authors.lastname: Domier
authors.affiliation: Department of Crop Sciences, University of Illinois, 1102 South Goodwin Ave. Urbana, IL, 61801, United States of America.
authors.forename: Biruk
authors.initials: B
authors.lastname: Gonfa
authors.affiliation: Department of Plant, Soil and Agricultural Systems, 1205 Lincoln Dr. Southern Illinois University, Carbondale, IL, 62901, United States of America.
authors.forename: Naoufal
authors.initials: N
authors.lastname: Lakhssassi
authors.affiliation: Department of Plant, Soil and Agricultural Systems, 1205 Lincoln Dr. Southern Illinois University, Carbondale, IL, 62901, United States of America.
authors.forename: Khalid
authors.initials: K
authors.lastname: Meksem
authors.affiliation: Department of Crop Sciences, University of Illinois, 1102 South Goodwin Ave. Urbana, IL, 61801, United States of America.
authors.forename: Kris N
authors.initials: KN
authors.lastname: Lambert
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001710:Biotin / Q000235:genetics / Q000378:metabolism*; D008040:Genetic Linkage; D023281:Genomics; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050600:SNARE Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013025:Glycine max / Q000469:parasitology*; D014431:Tylenchoidea / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*
chemical_list: D015801:Helminth Proteins; D012333:RNA, Messenger; D050600:SNARE Proteins; D001710:Biotin