Plant chromatin warms up in Madrid: meeting summary of the 3rd European Workshop on Plant Chromatin 2013, Madrid, Spain

Abstract

The 3rd European Workshop on Plant Chromatin (EWPC) was held on August 2013 in Madrid, Spain. A number of different topics on plant chromatin were presented during the meeting, including new factors mediating Polycomb Group protein function in plants, chromatin-mediated reprogramming in plant developmental transitions, the role of histone variants, and newly identified chromatin remodeling factors. The function of interactions between chromatin and transcription factors in the modulation of gene expression, the role of chromatin dynamics in the control of nuclear processes and the influence of environmental factors on chromatin organization were also reported. In this report, we highlight some of the new insights emerging in this growing area of research, presented at the 3rd EWPC.

Keywords: chromatin; chromatin reprogramming; development; epigenetics; plants.

Figure 1. PcG protein regulation of seed maturation genes. Interplay between PRC1 and PRC2 represses seed maturation genes following unexpected rules that challenge the traditional views on PcG protein function. Courtesy of M. Calonje (Seville, Spain).

Figure 2. H1 eviction marks the somatic-to-reproductive fate transition in Arabidopsis ovule primordia. H1.1-GFP (green) is present in all nucellar cells of the ovule primordium but is evicted upon differentiation of megaspore mother cells (MMC). This image shows an ago9–4 ovule primordium producing ectopic cells engaged in an ameiotic gametophytic fate, showing H1 eviction like wild type MMCs. Scale bar: 10 µm. Courtesy of C. Baroux (Zurich, Switzerland).

Figure 3. KNL2 colocalizes with cenH3. (A) Localization of KNL2 in meristematic interphase nucleus of A thaliana (in red) and DAPI counterstaining (blue). (B) Colocalization of cenH3 (left, green) and KNL2 (middle, red) in meristematic interphase nucleus of A. thaliana. Overlay and DAPI counterstaining (right). Courtesy of I. Lermontova (Gatersleben, Germany).

Figure 4. Coordinated replication in root meristem cell files is dependent on a SET-domain gene. Wild type (Col-0) and SET-domain gene mutant root meristems stained 1 h with the thymidine analog EdU to visualize DNA-replicating nuclei (in green and pink, respectively). The wild type image exemplifies a coordinated pattern, in this case along an endodermal (En) cell file, with a replicating singlet (1) nearest the quiescent center (QC), followed by a duplet (2), quartet (4) and octet (8) of co-replicating daughter, granddaughter and great-granddaughter cells. This coordinated replication pattern is distorted in the SET-domain gene mutant. C, cortex; Ep, epidermis. Courtesy of R. B. Aalen (Oslo, Norway); images by Robert Kumpf.