In vertebrates, the microtubule binding protein TPX2 is required for meiotic and mitotic spindle assembly. TPX2 is also known to bind to and activate Aurora A kinase and target it to the spindle. However, the relationship between the TPX2-Aurora A interaction and the role of TPX2 in spindle assembly is unclear. Here, we identify TPXL-1, a C. elegans protein that is the first characterized invertebrate ortholog of TPX2. We demonstrate that an essential role of TPXL-1 during mitosis is to activate and target Aurora A to microtubules. Our data suggest that this targeting stabilizes microtubules connecting kinetochores to the spindle poles. Thus, activation and targeting of Aurora A appears to be an ancient and conserved function of TPX2 that plays a central role in mitotic spindle assembly.

Salvia L. in its traditional circumscription is the largest genus within the mint family. To date, the magnitude of the task has rendered it difficult to provide a genus-wide revision based on morphological data. Current molecular investigations based on a dense taxon sampling representing the whole phenotypic diversity and distribution range of Salvia confirmed that the genus is polyphyletic. Salvia species fall in 4 distinct clades, although all of them, except Clade IV, also include non-Salvia genera. A taxonomic revision is thus urgently needed with two different approaches that have to be considered: (1) to include the 5 morphologically distinct non-Salvia genera in Salvia or (2) to split Salvia s.l. into Salvia s.s. and several additional genera. Since Salvia is already highly heterogeneous in species distribution, morphology, and chromosome number, we prefer to split the genus into molecularly well-supported clades. This new concept may facilitate monographic studies and more focused analyses of character evolution within or between the clades. Species representing Salvia sect. Eremosphace Bunge (subclade III-A) were chosen exemplarily to provide arguments for elevating this particular group to the level of genus (Pleudia Raf.).

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