Recruitment of an ancient branching program to suppress carpel development in maize flowers
11 de enero de 2022
Les invitamos a leer el artículo: "Recruitment of an ancient branching program to suppress carpel development in maize flowers" de la Dra. Jazmín Abraham Juárez, profesora investigadora de la UGA-Langebio.
Autores: Harry Klein, Joseph Gallagher, Edgar Demesa-Arevalo, Marıa Jazmın Abraham-Juarez, Michelle Heeney, Regina Feil, John E. Lunn, Yuguo Xiao, George Chuck, Clinton Whipple, David Jackson, and Madelaine Bartlett.
Felicitamos al estudiantado y profesorado que contribuyeron en esta investigación por su arduo trabajo.
Abstract: Carpels in maize undergo programmed cell death in half of the flowers initiated in ears and in all flowers in tassels. The HD-ZIP I transcription factor gene GRASSY TILLERS1 (GT1) is one of only a few genes known to regulate this process. To identify additional regulators of carpel suppression, we performed a gt1 enhancer screen and found a genetic interaction between gt1 and ramosa3 (ra3). RA3 is a classic inflorescence meristem determinacy gene that encodes a trehalose-6-phosphate (T6P) phosphatase (TPP). Dissection of floral development revealed that ra3 single mutants have partially derepressed carpels, whereas gt1;ra3 double mutants have completely derepressed carpels. Surprisingly, gt1 suppresses ra3 inflorescence branching, revealing a role for gt1 in meristem determinacy. Supporting these genetic interactions, GT1 and RA3 proteins colocalize to carpel nuclei in developing flowers. Global expression profiling revealed common genes misregulated in single and double mutant flowers, as well as in derepressed gt1 axillary meristems. Indeed, we found that ra3 enhances gt1 vegetative branching, similar to the roles for the trehalose pathway and GT1 homologs in the eudicots. This functional conservation over ∼160 million years of evolution reveals ancient roles for GT1-like genes and the trehalose pathway in regulating axillary meristem suppression, later recruited to mediate carpel suppression. Our findings expose hidden pleiotropy of classic maize genes and show how an ancient developmental program was redeployed to sculpt floral form.
Keywords: programmed cell death, RAMOSA3 (RA3), trehalose 6-phosphate, GRASSY TILLERS1 (GT1), evolution of flower development.