teosinte branched1 and the control of bud dormancy and growth in maize (Nature Comms)

Branching has a significant impact on plant architecture. Maize, a domesticated species, has lower branching levels in comparison to its wild ancestor teosinte. Axillary branching is the result of lateral buds growth. Some factors such as phytohormones and transport of sugars are related to bud activation/dormancy and hence branching. In a recent paper, Dong et al. studied the dynamics of bud dormancy at the transcriptomic level in maize.  They compared data from B73 to teosinte branched1 (tb1) and grassy tillers1 (gt1) two mutants that over-produce tillers and aerial branches. As a result, they obtained a set of genes involved in the regulation of bud dormancy. Their further analysis focussed on TB1 and its targets. Among these were genes involved in ABA synthesis and transport, and ABA signal transduction. Other hormonal processes identified included gibberellins; TB1 inhibits GA production and signaling, resulting in bud dormancy. Additionally, some TB1 targets control the sugar distribution; the levels of sucrose, fructose, and related metabolites were elevated in tb1 buds. TB1 also controls other domestication genes, such as tga1 and tru1, that regulates inflorescence architecture. As the authors conclude, “This places tb1 on top of the domestication hierarchy, demonstrating its critical importance during the domestication of maize from teosinte.” (Summary by Humberto Herrera-Ubaldo) Nature Comms. 10.1038/s41467-019-11774-w