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ARS Home » Pacific West Area » Albany, California » Plant Gene Expression Center » Research » Publications at this Location » Publication #347361
Title: GRF-interacting factor1 (GIF1) regulates shoot architecture and meristem determinacy in maize

Author
item ZHANG, D - Huazhong Agricultural University
item SUN, W - Huazhong Agricultural University
item SINGH, R - University Of California
item ZHENG, Y - Huazhong Agricultural University
item CAO, Z - Huazhong Agricultural University
item LI, M - Huazhong Agricultural University
item LUNDE, C - University Of California
item Hake, Sarah
item ZHANG, Z - Huazhong Agricultural University

Submitted to: The Plant Cell
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2018
Publication Date: 2/14/2018
Citation: Zhang, D., Sun, W., Singh, R., Zheng, Y., Cao, Z., Li, M., Lunde, C., Hake, S.C., Zhang, Z. 2018. GRF-interacting factor1 (GIF1) regulates shoot architecture and meristem determinacy in maize. The Plant Cell. 30(7):360-374. https://doi.org/10.1105/tpc.17.00791.
DOI: https://doi.org/10.1105/tpc.17.00791

Interpretive Summary: Plant architecture results from the activity of meristems, populations of dividing cells that are totipotent and indeterminate. The shoot apical meristem is an indeterminate meristem, initiating primordia indefinitely. Meristematic cells are also found in growing organs such as the stem or leaves, contributing to the height of the plant or width of a leaf. Meristematic cells lose their indeterminacy as their fate becomes determined. In the present study, we provide the first description of a gif1 loss of function mutant in maize. GIF1 promotes meristematic function in leaves and stems, but restricts indeterminacy in inflorescence meristems. We show that GIF1 binds the inflorescence architecture gene unbranched3, and regulates expressions of several known inflorescence architecture-related genes. We hypothesize that the unique maize targets explain the different phenotypes.

Technical Abstract: Plant architecture results from a balance of indeterminate and determinate cell fates. Cells with indeterminate fates are located in meristems, groups of pluripotent cells that produce lateral organs. Meristematic cells are also found in intercalary tissue of the stem that provides cells for internodes and at leaf margins to contribute to leaf width. We identified a mutant that has a defect in balancing determinacy and indeterminacy. The mutant has narrow leaves and short internodes suggesting a reduction in indeterminate cells in leaf and stem. In contrast, mutants fail to control indeterminacy in shoot meristems. Inflorescence meristems are fasciated and determinate axillary meristems become indeterminate. Positional cloning identified GROWTH REGULATING FACTOR- INTERACTING FACTOR1 (GIF1) as the responsible gene. GIF1 mRNA accumulates in distinct domains of shoot meristems, consistent with tissues affected by the mutation. We determined which GROWTH REGULATING FACTORs (GRFs) interact with GIF1 and carried out an RNA-seq analysis. Many genes known to play a role in inflorescence architecture were differentially expressed in gif1 mutants. Chromatin immunoprecipitation identified some of the differentially expressed genes as direct targets of GIF1. The direct and indirect targets help explain the paradoxical phenotypes of maize GIF1. These results provide new insight into the biological functions of GIF1.