Fungal Virulence and Development Is Regulated by Alternative Pre-mRNA 3′End Processing in Magnaporthe oryzae

RNA-binding proteins play a central role in post-transcriptional mechanisms that control gene expression. Identification of novel RNA-binding proteins in fungi is essential to unravel post-transcriptional networks and cellular processes that confer identity to the fungal kingdom. Here, we carried out the functional characterisation of the filamentous fungus-specific RNA-binding protein RBP35 required for full virulence and development in the rice blast fungus. RBP35 contains an N-terminal RNA recognition motif (RRM) and six Arg-Gly-Gly tripeptide repeats. Immunoblots identified two RBP35 protein isoforms that show a steady-state nuclear localisation and bind RNA in vitro. RBP35 coimmunoprecipitates in vivo with Cleavage Factor I (CFI) 25 kDa, a highly conserved protein involved in polyA site recognition and cleavage of pre-mRNAs. Several targets of RBP35 have been identified using transcriptomics including 14-3-3 pre-mRNA, an important integrator of environmental signals. In Magnaporthe oryzae, RBP35 is not essential for viability but regulates the length of 3′UTRs of transcripts with developmental and virulence-associated functions. The Δrbp35 mutant is affected in the TOR (target of rapamycin) signaling pathway showing significant changes in nitrogen metabolism and protein secretion. The lack of clear RBP35 orthologues in yeast, plants and animals indicates that RBP35 is a novel auxiliary protein of the polyadenylation machinery of filamentous fungi. Our data demonstrate that RBP35 is the fungal equivalent of metazoan CFI 68 kDa and suggest the existence of 3′end processing mechanisms exclusive to the fungal kingdom

Wetzeliella and its allies - the "hole story": a taxonomic revision of the Paleogene dinoflagellate subfamily Wetzelielloideae

Fossil dinoflagellate cysts of the Paleogene peridiniacean subfamily Wetzelielloideae have a stable tabulation pattern similar to that of other fossil peridiniaceans, but distinguished by a foursided (quadra) rather than a six-sided (hexa) 2a plate. Aside from tabulation, wetzelielloideans show great morphological variability, especially in ornamentation and horn development, but also in wall structure. This diversity has distracted attention from the morphological variation of the archeopyle, which, although always formed through loss of the 2a plate only, shows variations that we consider critical in unravelling the group's phylogeny. Important factors are the shape and relative dimensions of the archeopyle and whether the operculum is attached (adnate) or detached. These parameters allow us to define five archeopyle types: equiepeliform, hyperepeliform, hypersoleiform, latiepeliform and soleiform. Based primarily on archeopyle type and secondarily on wall and morphology and ornamentation, we recognise six genera with an equiepeliform archeopyle, four with a hyperepeliform archeopyle, five with a latiepeliform archeopyle, five with a soleiform archeopyle, and one with a hypersoleiform archeopyle. The earliest-known wetzelielloideans, which occur around the Paleocene‒Eocene boundary, have an equiepeliform archeopyle. Other archeopyle types evolved rapidly: taxa with hyperepeliform, latiepeliform and hypersoleiform types are known from the Ypresian. Latiepeliform and hyperepeliform types are restricted to the Ypresian and Lutetian. Forms with the soleiform archeopyle appeared in the late Lutetian, but were rare until the Bartonian, when they became the dominant type, and they were the only type in Priabonian and younger strata. Wetzelielloideans became extinct in the middle Oligocene. We make numerous taxonomic proposals, including the following new genera: Castellodinium, Dolichodinium, Epelidinium, Kledodinium, Michouxdinium, Petalodinium, Piladinium, Rhadinodinium, Sagenodinium, Sophismatia, Stenodinium, Stichodinium and Vallodinium. We emend the diagnoses of Charlesdowniea, Dracodinium and Wilsonidium, and erect the species Kledodinium filosum, Petalodinium sheppeyense and Sagenodinium franciscanum.Fil: Williams, Graham L.. Natural Resources Canada. Geological Survey of Canada (Atlantic); CanadáFil: Damassa, Sarah P..Fil: Fensome, Robert A.. Natural Resources Canada. Geological Survey of Canada (Atlantic); CanadáFil: Guerstein, Gladys Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Geológico del Sur; Argentina. Universidad Nacional del Sur; Argentin