Auxin signaling modules regulate maize inflorescence architecture

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 112; no. 43; pp. 13372 - 13377
• Main Authors: Galli, Mary, Liu, Qiujie, Moss, Britney L., Malcomber, Simon, Li, Wei, Gaines, Craig, Federici, Silvia, Roshkovan, Jessica, Meeley, Robert, Nemhauser, Jennifer L., Gallavotti, Andrea
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 27.10.2015; National Acad Sciences
• Subjects: Acetic acid; Bayes Theorem; Biological Sciences; Cloning, Molecular; Computational Biology; Corn; DNA Primers - genetics; Electrophoretic Mobility Shift Assay; Flowers - cytology; Flowers - growth & development; Gene Expression Regulation, Developmental - genetics; Gene Expression Regulation, Developmental - physiology; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - physiology; Genetics; Hormones; In Situ Hybridization; Indoleacetic Acids - metabolism; Meristem - growth & development; Meristem - metabolism; Models, Genetic; Phylogeny; Plant Proteins - genetics; Plant Proteins - metabolism; Plant reproduction; Protein expression; Real-Time Polymerase Chain Reaction; Reproduction; Signal transduction; Signal Transduction - physiology; Stem cells; Zea mays; Zea mays - growth & development; boundary domains; inflorescence development; axillary meristems; maize; auxin signaling
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1516473112

In plants, small groups of pluripotent stem cells called axillary meristems are required for the formation of the branches and flowers that eventually establish shoot architecture and drive reproductive success. To ensure the proper formation of new axillary meristems, the specification of boundary regions is required for coordinating their development. We have identified two maize genes,BARREN INFLORESCENCE1andBARREN INFLORESCENCE4(BIF1andBIF4), that regulate the early steps required for inflorescence formation.BIF1andBIF4encode AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins, which are key components of the auxin hormone signaling pathway that is essential for organogenesis. Here we show that BIF1 and BIF4 are integral to auxin signaling modules that dynamically regulate the expression of BARREN STALK1 (BA1), a basic helix-loop-helix (bHLH) transcriptional regulator necessary for axillary meristem formation that shows a striking boundary expression pattern. These findings suggest that auxin signaling directly controls boundary domains during axillary meristem formation and define a fundamental mechanism that regulates inflorescence architecture in one of the most widely grown crop species.