The march of the PINs: developmental plasticity by dynamic polar targeting in plant cells

The role of the Elongator complex in plants

The multi-subunit complex Elongator interacts with elongating RNA polymerase II (RNAPII) and is thought to facilitate transcription through histone acetylation. Elongator is conserved in eukaryotes, yet functions in diverse kingdom-specific processes. In this mini-review, we discuss the known functions of Elongator in plants, including its roles in development and responses to biotic and abiotic stresses. We propose that Elongator functions in these processes by accelerating gene induction in response to changing cellular and environmental conditions.

The vascular cambium: molecular control of cellular structure

Indeterminate growth and the production of new organs in plants require a constant supply of new cells. The majority of these cells are produced in mitotic regions called meristems. For primary or tip growth of the roots and shoots, the meristems are located in the apices. These apical meristems have been shown to function as developmentally regulated and environmentally responsive stem cell niches. The principle requirements to maintain a functioning meristem in a dynamic system are a balance of cell division and differentiation and the regulation of the planes of cell division and expansion. Woody plants also have secondary indeterminate mitotic regions towards the exterior of roots, stems and branches that produce the cells for continued growth in girth. The chief secondary meristem is the vascular cambium (VC). As its name implies, cells produced in the VC contribute to the growth in girth via the production of secondary vascular elements. Although we know a considerable amount about the cellular and molecular basis of the apical meristems, our knowledge of the cellular basis and molecular functioning of the VC has been rudimentary. This is now changing as a growing body of research shows that the primary and secondary meristems share some common fundamental regulatory mechanisms. In this review, we outline recent research that is leading to a better understanding of the molecular forces that shape the cellular structure and function of the VC.