Abstract
Investigation of protein targeting to plastids in plants by confocal laser scanning microscopy (CLSM) can be complicated by numerous sources of artifact, ranging from misinterpretations from in vivo protein over-expression, false fluorescence in cells under stress, and organellar mis-identification. Our studies have focused on the plant-specific gene MSH1, which encodes a dual targeting protein that is regulated in its expression and resides within the nucleoid of a specialized plastid type ( Virdi et al., 2016 ). Therefore, our methods have been optimized to study protein dual targeting to mitochondria and plastids, spatial and temporal regulation of protein expression, and sub-organellar localization, producing a protocol and set of experimental standards that others may find useful for such studies.