THE SWI/SNF COMPLEXESIn plants,as well as in metazoans,the execution of developmental programs and the response to environmental stimuli depend on changes in gene transcription programs that require extensive chromatin modifications of basically two types:posttranslational modification of histones and ATP-dependent reorganization of histones-DNA interactions.Many different nuclear machineries are necessary to carry out chromatin modifications at the appropriate time and place.Yeast SWI/SNF (switch/sucrose non-fermentable) was the first ATP-dependent chromatin-remodeling complex to be described in the 1980s.Since then,SWI/SNF complexes have been found in many eukaryotes,with functions ranging from control of development to genome stability (recently reviewed by Euskirchen et al.(2012)).