The SWI/SNF ATP-Dependent Chromatin Remodeling Complex in Arabidopsis Responds to Environmental Changes in Temperature-Dependent Manner

Abstract

SWI/SNF ATP-dependent chromatin remodeling complexes (CRCs) play important roles in the regulation of transcription, cell cycle, DNA replication, repair, and hormone signaling in eukaryotes. The core of SWI/SNF CRCs composed of a SWI2/SNF2 type ATPase, a SNF5 and two of SWI3 subunits is sufficient for execution of nucleosome remodeling in vitro. The Arabidopsis genome encodes four SWI2/SNF2 ATPases, four SWI3, a single SNF5 and two SWP73 subunits. Genes of the core SWI/SNF components have critical but not fully overlapping roles during plant growth, embryogenesis, and sporophyte development. Here we show that the Arabidopsis <i>swi3</i><i>c</i> mutant exhibits a phenotypic reversion when grown at lower temperature resulting in partial restoration of its embryo, root development and fertility defects. Our data indicates that the <i>swi3c</i> mutation alters the expression of several genes engaged in low temperature responses. The location of SWI3C-containing SWI/SNF CRCs on the <i>ICE1</i>, <i>MYB15</i> and <i>CBF1</i> target genes depends on the temperature conditions, and the <i>swi3c</i> mutation thus also influences the transcription of several cold-responsive (COR) genes. These findings, together with genetic analysis of <i>swi3c/ice1</i> double mutant and enhanced freezing tolerance of <i>swi3c</i> plants illustrate that SWI/SNF CRCs contribute to fine-tuning of plant growth responses to different temperature regimes.