title: Ancient diversity of splicing motifs and protein surfaces in the wild emmer wheat (Triticum dicoccoides) LR10 coiled coil (CC) and leucine-rich repeat (LRR) domains.
abstract: In this study, we explore the diversity and its distribution along the wheat leaf rust resistance protein LR10 three-dimensional structure. Lr10 is a leaf rust resistance gene encoding a coiled coil-nucleotide-binding site-leucine-rich repeat (CC-NBS-LRR) class of protein. Lr10 was cloned and sequenced from 58 accessions representing diverse habitats of wild emmer wheat in Israel. Nucleotide diversity was very high relative to other wild emmer wheat genes (π= 0.029). The CC domain was found to be the most diverse domain and subject to positive selection. Superimposition of the diversity on the CC three-dimensional structure showed that some of the variable and positively selected residues were solvent exposed and may interact with other proteins. The LRR domain was relatively conserved, but showed a hotspot of amino acid variation between two haplotypes in the ninth repeat. This repeat was longer than the other LRRs, and three-dimensional modelling suggested that an extensive α helix structure was formed in this region. The two haplotypes also differed in splicing regulation motifs. In genotypes with one haplotype, an intron was alternatively spliced in this region, whereas, in genotypes with the other haplotype, this intron did not splice at all. The two haplotypes are proposed to be ancient and maintained by balancing selection.
authors.affiliation: Department of Evolutionary and Environmental Biology, Institute of Evolution, University of Haifa, Mt. Carmel, Haifa 31905, Israel.
authors.forename: Hanan
authors.initials: H
authors.lastname: Sela
authors.forename: Laurentiu N
authors.initials: LN
authors.lastname: Spiridon
authors.forename: Andrei-Jose
authors.initials: AJ
authors.lastname: Petrescu
authors.forename: Martin
authors.initials: M
authors.lastname: Akerman
authors.forename: Yael
authors.initials: Y
authors.lastname: Mandel-Gutfreund
authors.forename: Eviatar
authors.initials: E
authors.lastname: Nevo
authors.forename: Caroline
authors.initials: C
authors.lastname: Loutre
authors.forename: Beat
authors.initials: B
authors.lastname: Keller
authors.forename: Alan H
authors.initials: AH
authors.lastname: Schulman
authors.forename: Tzion
authors.initials: T
authors.lastname: Fahima
mesh_terms: D000595:Amino Acid Sequence; D001487:Basidiomycota / Q000472:pathogenicity; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000235:genetics; D057865:Plant Immunity / Q000235:genetics / Q000502:physiology*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D014908:Triticum / Q000235:genetics / Q000276:immunology* / Q000378:metabolism* / Q000382:microbiology
chemical_list: D010940:Plant Proteins