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Significance Floral morphology is immensely diverse. One developmental process acting to shape this diversity is growth suppression. For example, grass flowers exhibit extreme diversity in floral sexuality, arising through differential suppression of stamens or carpels. The genes regulating this growth suppression and how they have evolved remain largely unknown. We discovered that two classic developmental genes with ancient roles in controlling vegetative branching were recruited to suppress carpel development in maize. Our results highlight the power of forward genetics to reveal unpredictable genetic interactions and hidden pleiotropy of developmental genes. More broadly, our findings illustrate how ancient gene functions are recruited to new developmental contexts in the evolution of plant form.
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GRASSY TILLERS1 ( GT1 ) and SIX-ROWED SPIKE1 ( VRS1 ) homologs share conserved roles in growth repression
Crop engineering and de novo domestication using gene editing are new frontiers in agriculture. However, outside of well-studied crops and model systems, prioritizing engineering targets remains challenging. Evolution can guide us, revealing genes with deeply conserved roles that have repeatedly been selected in the evolution of plant form. Homologs of the transcription factor genesGRASSY TILLERS1(GT1) andSIX-ROWED SPIKE1(VRS1) have repeatedly been targets of selection in domestication and evolution, where they repress growth in many developmental contexts. This suggests a conserved role for these genes in regulating growth repression. To test this, we determined the roles ofGT1andVRS1homologs in maize (Zea mays) and the distantly related grass brachypodium (Brachypodium distachyon) using gene editing and mutant analysis. In maize,gt1; vrs1-like1(vrl1) mutants have derepressed growth of floral organs. In addition,gt1; vrl1mutants bore more ears and more branches, indicating broad roles in growth repression. In brachypodium,Bdgt1;Bdvrl1mutants have more branches, spikelets, and flowers than wild-type plants, indicating conserved roles forGT1andVRS1homologs in growth suppression overca.59 My of grass evolution. Importantly, many of these traits influence crop productivity. Notably, maizeGT1can suppress growth in arabidopsis (Arabidopsis thaliana) floral organs, despiteca. 160 My of evolution separating the grasses and arabidopsis. Thus,GT1andVRS1maintain their potency as growth regulators across vast timescales and in distinct developmental contexts. This work highlights the power of evolution to inform gene editing in crop improvement.
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- Award ID(s):
- 1652380
- PAR ID:
- 10512402
- Publisher / Repository:
- NA
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 120
- Issue:
- 51
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1073/pnas.2311961120
