Mutations in HISTONE ACETYLTRANSFERASE1 affect sugar response and gene expression in Arabidopsis

Abstract

Nutrient response networks are likely to have been among the first response networks to evolve, as the ability to sense and respond to the levels of available nutrients is critical for all organisms. Although several forward genetic screens have been successful in identifying components of plant sugar-response networks, many components remain to be identified. Toward this end, a reverse genetic screen was conducted in Arabidopsis thaliana to identify additional components of sugar-response networks. This screen was based on the rationale that some of the genes involved in sugar-response networks are likely to be themselves sugar regulated at the steady-state mRNA level and to encode proteins with activities commonly associated with response networks. This rationale was validated by the identification of hac1 mutants that are defective in sugar response. HAC1 encodes a histone acetyltransferase. Histone acetyltransferases increase transcription of specific genes by acetylating histones associated with those genes. Mutations in HAC1 also cause reduced fertility, a moderate degree of resistance to paclobutrazol and altered transcript levels of specific genes. Previous research has shown that hac1 mutants exhibit delayed flowering. The sugar-response and fertility defects of hac1 mutants may be partially explained by decreased expression of AtPV42a and AtPV42b, which are putative components of plant SnRK1 complexes. SnRK1 complexes have been shown to function as central regulators of plant nutrient and energy status. Involvement of a histone acetyltransferase in sugar response provides a possible mechanism whereby nutritional status could exert long-term effects on plant development and metabolism.

WRKY18 and WRKY53 Coordinate with HISTONE ACETYLTRANSFERASE1 to Regulate Rapid Responses to Sugar

“…Although hac1-4 was previously identified as a Glc and Suc insensitive mutant (Heisel et al, 2013), to the best of our knowledge, the mechanism by which HAC1 participates in sugar signaling has not been explored in any plant species. In our study, HAC1mediated acetylation of H3K27 was discovered to be one of the mechanisms associated with rapid sugar signaling (Fig.…”

Master regulators in plant glucose signaling networks

“…The application of super-resolution fluorescence microscopy (Doksani et al, 2013) will provide dynamic view of regulatory proteins in HXK1-mediated glucose signaling at single-molecule details in different subcellular compartments. It will be interesting to learn whether the E3 ligase, protein kinase and histone acetyltransferase identified through Arabidopsis sugar-response mutants may act downstream or independent of HXK1-mediated glucose signaling (Huang et al, 2010; Heisel et al, 2013: Huang et al, 2013). …”

Transcriptome analysis in Coffea eugenioides, an Arabica coffee ancestor, reveals differentially expressed genes in leaves and fruits

“…This transcription factor was related to locus AT4G18650.1 in Arabidopsis that encoded a DOG1-like 4 (DOGL4) transcription factor. DOGL4 is a member of a small gene family that includes DOG1, which functions in the control of seed dormancy (Heisel et al 2013). However, the function of DOGL4 is currently unknown (Bentsink et al 2006).…”