Natural selection of a GSK3 determines rice mesocotyl domestication by coordinating strigolactone and brassinosteroid signaling

Nat Commun. 2018 Jun 28;9(1):2523. doi: 10.1038/s41467-018-04952-9.

Abstract

Mesocotyl is the crucial organ for pushing buds out of deep water or soil after germination in monocots. Deep direct seeding or mechanized dry seeding cultivation practice requires rice cultivars having long mesocotyl. However, the mechanisms of mesocotyl elongation and domestication remain unknown. Here, our genome-wide association study (GWAS) reveals that natural variations of OsGSK2, a conserved GSK3-like kinase involved in brassinosteroid signaling, determine rice mesocotyl length variation. Variations in the coding region of OsGSK2 alter its kinase activity. It is selected for mesocotyl length variation during domestication. Molecular analyses show that brassinosteroid-promoted mesocotyl elongation functions by suppressing the phosphorylation of an U-type cyclin, CYC U2, by OsGSK2. Importantly, the F-box protein D3, a major positive component in strigolactone signaling, can degrade the OsGSK2-phosphorylated CYC U2 to inhibit mesocotyl elongation. Together, these results suggest that OsGSK2 is selected to regulate mesocotyl length by coordinating strigolactone and brassinosteroid signaling during domestication.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brassinosteroids / metabolism*
  • Domestication
  • F-Box Proteins / genetics
  • F-Box Proteins / metabolism
  • Gene Expression Regulation, Plant*
  • Genome, Plant*
  • Germination / genetics
  • Glycogen Synthase Kinase 3 / genetics*
  • Glycogen Synthase Kinase 3 / metabolism
  • Lactones / metabolism
  • Oryza / genetics*
  • Oryza / growth & development
  • Oryza / metabolism
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plant Stems / anatomy & histology
  • Plant Stems / genetics*
  • Plant Stems / growth & development
  • Plant Stems / metabolism
  • Seedlings / genetics
  • Seedlings / growth & development
  • Seedlings / metabolism
  • Seeds / genetics
  • Seeds / growth & development
  • Seeds / metabolism
  • Selection, Genetic
  • Signal Transduction
  • Uracil-DNA Glycosidase / genetics
  • Uracil-DNA Glycosidase / metabolism

Substances

  • Brassinosteroids
  • F-Box Proteins
  • Lactones
  • Plant Proteins
  • Glycogen Synthase Kinase 3
  • Uracil-DNA Glycosidase