The trithorax group factor ULTRAPETALA1 regulates developmental as well as biotic and antibiotic stress response genes in Arabidopsis

Authors: TYLER, LUDMILA - University Of California; MILLER, MARK - University Of California; Fletcher, Jennifer

Submitted to: G3, Genes/Genomes/Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2019
Publication Date: 10/11/2019
Citation: Tyler, L., Miller, M., Fletcher, J.C. 2019. The trithorax group factor ULTRAPETALA1 regulates developmental as well as biotic and antibiotic stress response genes in Arabidopsis. G3, Genes/Genomes/Genetics. 9(12):4029-4043. https://doi.org/10.1534/g3.119.400559.
DOI: https://doi.org/10.1534/g3.119.400559

Interpretive Summary: Genes called trithorax group (trxG) factors are critical for plant growth because they help coordinate the expression of large groups of downstream genes during development and in response to changes in their environment. Compared to their animal counterparts, plant trxG factors and their downstream target genes are poorly understood. We have used a method called microarray transcriptomics analysis to identify all the downstream targets of an Arabidopsis trxG factor called ULTRAPETALA1 (ULT1), which is an important regulator of plant architecture and yield. We found that many ULT target genes are involved in development and in regulating gene expression. In addition we discovered that ULT1 regulates many genes involved in plant defense responses to pathogens and insects, as well as those involved in various external stress responses. This finding positions ULT1 as a key gene that controls how plants alter their growth in response to fluctuations in their environment.

Technical Abstract: In eukaryotes, Polycomb group (PcG) and trithorax group (trxG) factors oppositely regulate gene transcription during development through histone modifications, with PcG factors repressing and trxG factors activating the expression of their target genes. Although plant trxG factors regulate many developmental and physiological processes, their downstream targets are poorly characterized. Here we use transcriptomics to identify genome-wide targets of the Arabidopsis thaliana trxG factor ULTRAPETALA1 (ULT1) during vegetative and reproductive development, and compare them with those of the PcG factor CURLY LEAF (CLF). We find that genes involved in development and transcription regulation are over-represented among ULT1 target genes. In addition, stress response genes and defense response genes such as those in glucosinolate metabolic pathways are enriched, revealing a previously unknown role for ULT1 in controlling biotic and abiotic responses. Finally, we show that many ULT1 target genes can be oppositely regulated by CLF, suggesting that ULT1 and CLF may have antagonistic effects on plant growth and development in response to various endogenous and environmental cues.