Open AccessARABIDOPSIS THALIANA HOMEOBOX GENE 1 controls plant architecture by locally restricting environmental responses
Author(s) -
Mahwish Ejaz,
Stefano Bencivenga,
Rafael Garcia Tavares,
Maxwell S. Bush,
Robert Sablowski
Publication year - 2021
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2018615118
Subject(s) - biology , arabidopsis , homeobox , arabidopsis thaliana , phytochrome , gene , microbiology and biotechnology , rosette (schizont appearance) , gibberellin , regulation of gene expression , genetics , transcription factor , botany , mutant , red light , immunology
The diversity and environmental plasticity of plant growth results from variations of repetitive modules, such as the basic shoot units made of a leaf, axillary bud, and internode. Internode elongation is regulated both developmentally and in response to environmental conditions, such as light quality, but the integration of internal and environmental signals is poorly understood. Here, we show that the compressed rosette growth habit of Arabidopsis is maintained by the convergent activities of the organ boundary gene ARABIDOPSIS THALIANA HOMEOBOX GENE 1 ( ATH1 ) and of the gibberellin-signaling DELLA genes. Combined loss of ATH1 and DELLA function activated stem development during the vegetative phase and changed the growth habit from rosette to caulescent. Chromatin immunoprecipitation high-throughput sequencing and genetic analysis indicated that ATH1 and the DELLA gene REPRESSOR OF GA1-3 ( RGA ) converge on the regulation of light responses, including the PHYTOCHROME INTERACTING FACTORS ( PIF ) pathway, and showed that the ATH1 input is mediated in part by direct activation of BLADE ON PETIOLE ( BOP1 and BOP2 ) genes, whose products destabilize PIF proteins. We conclude that an organ-patterning gene converges with hormone signaling to spatially restrict environmental responses and establish a widespread type of plant architecture.