A brachytic dwarfism trait ( dw ) in peach trees is caused by a nonsense mutation within the gibberellic acid receptor PpeGID1c

Summary Little is known about the genetic factors controlling tree size and shape. Here, we studied the genetic basis for a recessive brachytic dwarfism trait ( dw ) in peach ( Prunus persica ) that has little or no effect on fruit development. A sequencing‐based mapping strategy positioned dw on the distal end of chromosome 6. Further sequence analysis and fine mapping identified a candidate gene for dw as a non‐functional allele of the gibberellic acid receptor GID1c . Expression of the two GID1‐like genes found in peach, PpeGID1c and PpeGID1b , was analyzed. GID1c was predominantly expressed in actively growing vegetative tissues, whereas GID1b was more highly expressed in reproductive tissues. Silencing of GID1c in plum via transgenic expression of a hairpin construct led to a dwarf phenotype similar to that of dw/dw peaches. In general, the degree of GID1c silencing corresponded to the degree of dwarfing. The results suggest that PpeGID1c serves a primary role in vegetative growth and elongation, whereas GID1b probably functions to regulate gibberellic acid perception in reproductive organs. Modification of GID1c expression could provide a rational approach to control tree size without impairing fruit development.