Hierarchical probes at various taxonomic levels in the Haptophyta and a new division level probe for the Heterokonta

We present a set of specific ribosomal RNA probes for the Haptophyta and a new probe for the Heterokonta, which, in combination with previously described probes, will allow for the rapid stepwise characterization of phytoplankton samples for marine plankton members of these algal divisions by fluorescence in situ hybridization. Probes are described for the Haptophyta Classes Prymnesiophyceae and Pavlovaphyceae, for the Order Cocccolithales, for clades known only from clone library sequence data and for the genus Prymnesium. The division level probe for the Heterokonta presented here mismatches only 4.5% of all heterokonts, where the complete 18S rDNA is known. It does not target any organism outside the heterokonts, expect for two environmental clones, which could be chimeras. The heterokonts not targeted by this probe fall mostly in the non-pigmented clades at the base of the heterokont tree. When this probe is coupled with other published class level probes, the biodiversity of the heterokont classes can be addressed by fluorescence in situ hybridizations.