Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors

Abstract

To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes.

The Distinct Roles of Class I and II RPD3-Like Histone Deacetylases in Salinity Stress Response

“…Previous studies have reported the defense-related properties of compounds with HDI activity, which inhibits the growth of competing organisms. Venturelli et al (2015) demonstrated that plants release aminophenoxazinone compounds, such as 2-amino-3H-phenoxazin-3-one Figure 6. Increased tolerance of quint plants to salinity stress conditions.…”

Plant defense and herbivore counter-defense: benzoxazinoids and insect herbivores

“…BXD hydroxamic acids possess metal ion chelating properties (Tipton and Buell 1970) that can play a role in Fe(III) uptake (Pethő 1992a, b, 1993, 2002) and Al(III) resistance by roots (Poschenrieder et al 2005). Furthermore, benzoxazolinones can interfere with auxin binding in plants (Hasegawa et al 1992; Hoshisakoda et al 1994; Venis and Watson 1978), and the products of their metabolism by soil microorganisms are suggested to play a role in allelopathy (Kato-Noguchi et al 2010; Schulz et al 2013; Venturelli et al 2015). …”

Allelochemicals of the phenoxazinone class act at physiologically relevant concentrations

“…2 This particular class of allelochemicals derives from the cyclic hydroxamic acids DIBOA (4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one) and DIMBOA (2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one), which are contained in root exudates from many grasses, among them several major crops such as wheat, rice and maize. 3,4 We were able to show that APO and AMPO have the potential to bind to histone deacetylases (HDACs), 2 an evolutionarily highly conserved class of enzymes that govern the accessibility of the DNA by removal of acetyl groups from various amino acid residues of histone proteins. Histone acetylation is a dynamic epigenetic mark that correlates with relaxed chromatin conformation, accessible DNA and transcriptional activity (Fig.…”

“…2 Making use of the higher solubility of APO in DMSO, we have established experimental conditions that better reflect physiologically relevant conditions. This setup will not only allow improved realism in future experiments, but will also drastically reduce costs, as APO is not commercially available and needs to be custom synthesized.…”