Greenwood, JulianFinnegan, E. JeanWatanabe, NobuyoshiTrevaskis, BenSwain, Steve M2021-08-182021-08-180950-1991http://hdl.handle.net/1885/244004The advantages of free threshing in wheat led to the selection of the domesticated Q allele, which is now present in almost all modern wheat varieties. Q and the pre-domestication allele, q, encode an AP2 transcription factor, with the domesticated allele conferring a free-threshing character and a subcompact (i.e. partially compact) inflorescence (spike). We demonstrate that mutations in the miR172 binding site of the Q gene are sufficient to increase transcript levels via a reduction in miRNA-dependent degradation, consistent with the conclusion that a single nucleotide polymorphism in the miRNA binding site of Q relative to q was essential in defining the modern Q allele. We describe novel gain- and loss-of-function alleles of Q and use these to define new roles for this gene in spike development. Q is required for the suppression of ‘sham ramification’, and increased Q expression can lead to the formation of ectopic florets and spikelets (specialized inflorescence branches that bear florets and grains), resulting in a deviation from the canonical spike and spikelet structures of domesticated wheat.This work was supported by an Australian National University (ANU) University Research Scholarship and a Commonwealth Scientific and Industrial Research Organisation (CSIRO) OCE PhD Top-up Scholarshipapplication/pdfen-AU© 2017. Published by The Company of Biologists LtdWheatSpikeInflorescenceAP2DomesticationmicroRNA201710.1242/dev.1464072020-11-23