PMID:23355632

Citation	Derbyshire, P and Byrne, ME (2013) MORE SPIKELETS1 is required for spikelet fate in the inflorescence of Brachypodium. Plant Physiol. 161:1291-302
Abstract	Grasses produce florets on a structure called a spikelet, and variation in the number and arrangement of both branches and spikelets contributes to the great diversity of grass inflorescence architecture. In Brachypodium (Brachypodium distachyon), the inflorescence is an unbranched spike with a terminal spikelet and a limited number of lateral spikelets. Spikelets are indeterminate and give rise to a variable number of florets. Here, we provide a detailed description of the stages of inflorescence development in Brachypodium. To gain insight into the genetic regulation of Brachypodium inflorescence development, we generated fast neutron mutant populations and screened for phenotypic mutants. Among the mutants identified, the more spikelets1 (mos1) mutant had an increased number of axillary meristems produced from inflorescence meristem compared with the wild type. These axillary meristems developed as branches with production of higher order spikelets. Using a candidate gene approach, mos1 was found to have a genomic rearrangement disrupting the expression of an ethylene response factor class of APETALA2 transcription factor related to the spikelet meristem identity genes branched silkless1 (bd1) in maize (Zea mays) and FRIZZY PANICLE (FZP) in rice (Oryza sativa). We propose MOS1 likely corresponds to the Brachypodium bd1 and FZP ortholog and that the function of this gene in determining spikelet meristem fate is conserved with distantly related grass species. However, MOS1 also appears to be involved in the timing of initiation of the terminal spikelet. As such, MOS1 may regulate the transition to terminal spikelet development in other closely related and agriculturally important species, particularly wheat (Triticum aestivum).
Links	PubMed PMC3585597 Online version:10.1104/pp.112.212340
Keywords
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
BRADI:I1GRF0		GO:0010229: inflorescence development			P		Seeded From UniProt	complete
BRADI:A0A0Q3JRW7		GO:0010229: inflorescence development	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Figure 4C and table II show that during reproductive growth, mos1 inflorescence produced approximately twice the number of lateral spikelets compared to wild type. Figure 5C shows that in mos1 the branch axillary meristems formed lateral spikelets as the branches transitioned to the awn initiation stage.	complete CACAO 8246

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