26 research outputs found
Cross activity of orthologous WRKY transcription factors in wheat and Arabidopsis
WRKY proteins are transcription factors involved in many plant processes including plant responses to pathogens. Here, the cross activity of TaWRKY78 from the monocot wheat and AtWRKY20 from the dicot Arabidopsis on the cognate promoters of the orthologous PR4-type genes wPR4e and AtHEL of wheat and Arabidopsis, respectively, was investigated. In vitro analysis showed the ability of TaWRKY78 to bind a –17/+80 region of the wPR4e promoter, containing one cis-acting W-box. Moreover, transient expression analysis performed on both TaWRKY78 and AtWRKY20 showed their ability to recognize the cognate cis-acting elements present in the wPR4e and AtHEL promoters, respectively. Finally, this paper provides evidence that both transcription factors are able to cross-regulate the orthologous PR4 genes with an efficiency slightly lower than that exerted on the cognate promoters. The observation that orthologous genes are subjected to similar transcriptional control by orthologous transcription factors demonstrates that the terminal stages of signal transduction pathways leading to defence are conserved and suggests a fundamental role of PR4 genes in plant defence. Moreover, these results corroborate the hypothesis that gene orthology imply similar gene function and that diversification between monocot and dicot has most likely occurred after the specialization of WRKY function
A class-wide phylogenetic assessment of Dothideomycetes
We present a comprehensive phylogeny derived from 5 genes, nucSSU, nucLSU
rDNA, TEF1, RPB1 and RPB2, for 356 isolates and 41
families (six newly described in this volume) in Dothideomycetes. All
currently accepted orders in the class are represented for the first time in
addition to numerous previously unplaced lineages. Subclass
Pleosporomycetidae is expanded to include the aquatic order
Jahnulales. An ancestral reconstruction of basic nutritional modes
supports numerous transitions from saprobic life histories to plant associated
and lichenised modes and a transition from terrestrial to aquatic habitats are
confirmed. Finally, a genomic comparison of 6 dothideomycete genomes with
other fungi finds a high level of unique protein associated with the class,
supporting its delineation as a separate taxon