A toolkit for studying cellular reorganization during early Arabidopsis thaliana embryogenesis (Plant J.) ($)

Embryogenesis is the simple process of plant development, but until recently our knowledge has been limited to how individual cells are specified and organized. Reported markers have been mostly constitutive promoter-driven, a fact that creates background and makes them unsuitable for the study of cellular organization of the embryo. In Liao & Weijers, the authors generated a set of ACE (Arabidopsis Cellular markers for Embryogenesis). These are fluorescent proteins that localize to various subcellular locations driven by meristematic (RPS5A, ACE-R) and embryo-specific (WOX2, ACE-W) promoters. ACE-R constructs are expressed uniformly in the embryo, whereas ACE-W lines are expressed in specific cells (in the pro-embryo, two uppermost suspensor cells; in the chalaza from 2-cell to early globular stage). Interestingly, ACE-W expression starts to decrease after early globular stage in the basal part of the embryo and two top most cells in the suspensor. In summary, ACE-R is suitable for study the suspensor, embryo proper and seed development; while ACE-W is more appropriate for early embryo imaging. This new set of markers will help to answer the fundamental questions regarding embryogenesis in the future. (Summary by Arif Ashraf ) Plant Journal 10.1111/tpj.13841