title: Differential coupling of gibberellin responses by Rht-B1c suppressor alleles and Rht-B1b in wheat highlights a unique role for the DELLA N-terminus in dormancy.
abstract: During the Green Revolution, substantial increases in wheat (Triticum aestivum) yields were realized, at least in part, through the introduction of the Reduced height (Rht)-B1b and Rht-D1b semi-dwarfing alleles. In contrast to Rht-B1b and Rht-D1b, the Rht-B1c allele is characterized by extreme dwarfism and exceptionally strong dormancy. Recently, 35 intragenic Rht-B1c suppressor alleles were created in the spring wheat cultivar Maringá, and termed overgrowth (ovg) alleles. Here, 14 ovg alleles with agronomically relevant plant heights were reproducibly classified into nine tall and five semi-dwarf alleles. These alleles differentially affected grain dormancy, internode elongation rate, and coleoptile and leaf lengths. The stability of these ovg effects was demonstrated for three ovg alleles in different genetic backgrounds and environments. Importantly, two semi-dwarf ovg alleles increased dormancy, which correlated with improved pre-harvest sprouting (PHS) resistance. Since no negative effects on grain yield or quality were observed, these semi-dwarf ovg alleles are valuable for breeding to achieve adequate height reduction and protection of grain quality in regions prone to PHS. Furthermore, this research highlights a unique role for the first 70 amino acids of the DELLA protein, encoded by the Rht-1 genes, in grain dormancy.
authors.affiliation: R&D Innovation Center, Bayer CropScience, Ghent, Belgium.|Ghent University, Department of Physiology, Laboratory of Functional Plant Biology, Ghent, Belgium.
authors.forename: Karel
authors.initials: K
authors.lastname: Van De Velde
authors.affiliation: CSIRO Plant Industry, Canberra, ACT 2601, Australia.
authors.forename: Peter Michael
authors.initials: PM
authors.lastname: Chandler
authors.affiliation: Ghent University, Department of Physiology, Laboratory of Functional Plant Biology, Ghent, Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: Van Der Straeten
authors.affiliation: R&D Innovation Center, Bayer CropScience, Ghent, Belgium.
authors.forename: Antje
authors.initials: A
authors.lastname: Rohde
mesh_terms: D000483:Alleles; D005875:Gibberellins / Q000378:metabolism*; D057445:Plant Dormancy; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D014908:Triticum / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D005875:Gibberellins; D010940:Plant Proteins; C120413:RHT-D1A protein, Triticum aestivum
keywords: DELLA; dormancy; gibberellin (GA); pre-harvest sprouting; suppressor alleles; wheat