Histone Acetyltransferase GCN5 Affects Auxin Transport during Root Growth by Modulating Histone Acetylation and Gene Expression of PINs

• Published in: Plants (Basel) 2022-12, Vol.11 (24), p.3572
• Main Authors: Poulios, Stylianos, Tsilimigka, Foteini, Mallioura, Areti, Pappas, Dimitris, Seira, Eleftheria, Vlachonasios, Konstantinos
• Format: Article
• Language: English
• Subjects: Acetylation; ADA2b; Analysis; Arabidopsis; Arabidopsis thaliana; Auxin; Auxins; Biosynthesis; Carrier proteins; Dwarfism; Efflux; Elongation; GCN5; Gene expression; Genes; Genetic aspects; Genetic research; Genotype & phenotype; Germination; Growth; histone acetylation; Histone acetyltransferase; Histone H3; Histones; Influence; Localization; Lysine; Mutants; Mutation; Phenotypes; PIN1; Pin1 protein; PIN3; Plant growth; Protein transport; Proteins; Root development; root meristem; Roots; Roots (Botany); Transcription factors
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants11243572

General Control Non-Derepressible 5 (GCN5) is a histone acetyltransferase that targets multiple genes and is essential for the acetylation of Lysine residues in the N-terminal tail of histone H3 in Arabidopsis. GCN5 interacts with the transcriptional coactivator Alteration/Deficiency in Activation 2b (ADA2b), which enhances its activity functioning in multiprotein complexes, such as the Spt-Ada-Gcn5-Acetyltransferase complex (SAGA). Mutations in and result in pleiotropic phenotypes, including alterations in the growth of roots. Auxin is known to regulate root development by modulating gene expression patterns. Auxin moves polarly during plant growth via the Pin-formed (PIN) auxin efflux transport proteins. The effect of GCN5 and ADA2b on auxin distribution at different stages of early root growth (4 to 7 days post-germination) was studied using the reporter lines and . In wild-type plants, auxin efflux transporter PIN1 expression increases from the fourth to the seventh day of root growth. The PIN1 expression was reduced in the roots of and compared to the wild type. The expression of PIN1 in mutants is confined only to the meristematic zone, specifically in the stele cells, whereas it is almost abolished in the elongation zone. Gene expression analysis showed that genes associated with auxin transport, , and , are downregulated in and mutants relative to the wild type. As a result, auxin accumulation was also reduced in and compared to wild-type roots. Furthermore, acetylation of Lysine 14 of histone H3 (H3K14) was also affected in the promoter and coding region of , and genes during root growth of Arabidopsis in mutants. In conclusion, GCN5 acts as a positive regulator of auxin distribution in early root growth by modulating histone H3 acetylation and the expression of auxin efflux transport genes.