No abstract

No abstract

Aims:  To develop a DNA microarray for easy and fast detection of trichothecene‐ and moniliformin‐producing Fusarium species. Method and Results:  A DNA microarray was developed for detection and identification of 14 trichothecene‐ and moniliformin‐producing species of the fungal genus Fusarium. The array could also differentiate between four species groups. Capture probes were designed based on recent phylogenetic analyses of translation elongation factor‐1 alpha (TEF‐1α) sequences. Particular emphasis was put on designing capture probes corresponding to groups or species with particular mycotoxigenic synthetic abilities. A consensus PCR amplification of a part of the TEF‐1α is followed by hybridization to the Fusarium chip and the results are visualized by a colorimetric Silverquant detection method. We validated the Fusarium chip against five naturally infected cereal samples for which we also have morphological and chemical data. The limit of detection was estimated to be less than 16 copies of genomic DNA in spiked commercial wheat flour. Conclusions:  The current Fusarium chip proved to be a highly sensitive and fast microarray for detection and identification of Fusarium species. We postulate that the method also has potential for (semi‐)quantification. Significance and Impact of the Study:  The Fusarium chip may prove to be a very valuable tool for screening of cereal samples in the food and feed production chain, and may facilitate detection of new or introduced Fusarium spp.

No abstract

Rho GTPases regulate a number of important cellular functions in eukaryotes, such as organization of the cytoskeleton, stress-induced signal transduction, cell death, cell growth, and differentiation. We have conducted an extensive screening, characterization, and analysis of genes belonging to the Ras superfamily of GTPases in land plants (embryophyta) and found that the Rho family is composed mainly of proteins with homology to RAC-like proteins in terrestrial plants. Here we present the genomic and cDNA sequences of the RAC gene family from the plant Arabidopsis thaliana. On the basis of amino acid alignments and genomic structure comparison of the corresponding genes, the 11 encoded AtRAC proteins can be divided into two distinct groups of which one group apparently has evolved only in vascular plants. Our phylogenetic analysis suggests that the plant RAC genes underwent a rapid evolution and diversification prior to the emergence of the embryophyta, creating a group that is distinct from rac/cdc42 genes in other eukaryotes. In embryophyta, RAC genes have later undergone an expansion through numerous large gene duplications. Five of these RAC duplications in Arabidopsis thaliana are reported here. We also present an hypothesis suggesting that the characteristic RAC proteins in higher plants have evolved to compensate the loss of RAS proteins.