Overgrowth mutants determine the causal role of gibberellin GA2oxidaseA13 in Rht12 dwarfism of wheat

This study showed that Rht14, an independent mutant that was generated in a different tetraploid background, increased the expression of the same GA 2-oxidase gene member that resulted in a dwarf phenotype

Wolfram Buss; Brett A Ford; Eloise Foo; Wendelin Schnippenkoetter; Philippa Borrill; Brenton Brooks; Anthony R Ashton; Peter M Chandler; Wolfgang Spielmeyer

2020

Scholarcy highlights

  • The Rht12 dwarfing gene is not associated with reduced coleoptile length and it is dominant, characteristics which are shared with the previously characterized dwarfing genes Rht18 and Rht14
  • Our study provides the functional proof that a GA 2-oxidase gene member on chromosome 5A is responsible for Rht12 dwarfism
  • If the overexpression of a GA 2-oxidase gene reduces bioactive GA content in Rht12, it was hypothesized that ovg mutants could be generated in a Rht12 background, as they were for Rht18
  • The results presented here support the hypothesis that Rht12 dwarfism is due to a lower content of bioactive GA1
  • Our findings confirm the candidate gene for Rh12 previously reported by Sun et al who showed that dwarfism was associated with increased expression of GA2oxA13 and a lower GA content
  • Reduced early growth and shorter coleoptiles can lead to poor crop establishment and increased water loss from the soil surface. This is relevant for rainfed, semi-arid environments where up to 50% of soil water can be lost from the surface due to evaporation during the early growth phase
  • The current study provides additional evidence by reporting loss-of-function mutations within GA2oxA13 that resulted in tall phenotypes with an associated increase in GA1 content
  • We previously observed ovg mutants with loss-of-function mutations in GA2oxA9 that were taller than parental lines in Halberd and durum wheat backgrounds

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