The histone acetyltransferase GCN5 and the transcriptional coactivator ADA2b affect leaf development and trichome morphogenesis in Arabidopsis

Abstract

The histone acetyltransferase GCN5 and associated transcriptional coactivator ADA2b are required to couple endoreduplication and trichome branching. Mutation of ADA2b also disrupts the relationship between ploidy and leaf cell size. Dynamic chromatin structure has been established as a general mechanism by which gene function is temporally and spatially regulated, but specific chromatin modifier function is less well understood. To address this question, we have investigated the role of the histone acetyltransferase GCN5 and the associated coactivator ADA2b in developmental events in Arabidopsis thaliana. Arabidopsis plants with T-DNA insertions in GCN5 (also known as HAG1) or ADA2b (also known as PROPORZ1) display pleiotropic phenotypes including dwarfism and floral defects affecting fertility. We undertook a detailed characterization of gcn5 and ada2b phenotypic effects in rosette leaves and trichomes to establish a role for epigenetic control in these developmental processes. ADA2b and GCN5 play specific roles in leaf tissue, affecting cell growth and division in rosette leaves often in complex and even opposite directions. Leaves of gcn5 plants display overall reduced ploidy levels, while ada2b-1 leaves show increased ploidy. Endoreduplication leading to increased ploidy is also known to contribute to normal trichome morphogenesis. We demonstrate that gcn5 and ada2b mutants display alterations in the number and patterning of trichome branches, with ada2b-1 and gcn5-1 trichomes being significantly less branched, while gcn5-6 trichomes show increased branching. Elongation of the trichome stalk and branches also vary in different mutant backgrounds, with stalk length having an inverse relationship with branch number. Taken together, our data indicate that, in Arabidopsis, leaves and trichomes ADA2b and GCN5 are required to couple nuclear content with cell growth and morphogenesis.

Updates on molecular mechanisms in the development of branched trichome in Arabidopsis and nonbranched in cotton

“…In addition, noncoding RNAs also play important roles in plant development as epigenetic regulators (Boyko and Kovalchuk, ; Davila‐Velderrain et al ., ; Grant‐Downton and Dickinson, ; Steimer et al ., ; Yamamuro et al ., ). A recent study showed that a multifunctional histone acetyltransferase, AtGCN5, positively influences trichome branching with possible regulation of TRY (Kotak et al ., ). On the other hand, through regulating histone acetylation of the promoters of GL1, GL2, GL3 and CPC, GCN5 is also involved trichome initiation regulation (Wang et al ., ).…”

Identification of Homeobox Genes Associated with Lignification and Their Expression Patterns in Bamboo Shoots

“…To identify the members of HB genes in moso bamboo, the previously identified HB genes of Arabidopsis thaliana and Oryza sativa were retrieved from the database TAIR 10.0 (The Arabidopsis Information Resource, https://www.arabidopsis.org/) and RGAP 7.0 (Rice Genome Annotation Project, http://rice.plantbiology.msu.edu/), respectively [37,38], and were used as queries in BLAST searches against the database of the moso bamboo genome (BambooGDB, http://bamboo.bamboogdb.org/) [28]. The sequences were selected for further analysis if the E-value was less than 1 × 10 −10 .…”

The Histone Acetyltransferase GCN5 and the Associated Coactivators ADA2: From Evolution of the SAGA Complex to the Biological Roles in Plants

“…GCN5 and ADA2b affect the developmental transition from the juvenile to adult phase by controlling the expression of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) factors [65]. GCN5 and ADA2b also affect several aspects of leaf cell growth and division, including in endoreduplication and trichome morphology [66,67].…”