The Clubroot Pathogen (\u3ci\u3ePlasmodiophora brassicae\u3c/i\u3e) Influences Auxin Signaling to Regulate Auxin Homeostasis in Arabidopsis

The clubroot disease, caused by the obligate biotrophic protist Plasmodiophora brassicae, affects cruciferous crops worldwide. It is characterized by root swellings as symptoms, which are dependent on the alteration of auxin and cytokinin metabolism. Here, we describe that two different classes of auxin receptors, the TIR family and the auxin binding protein 1 (ABP1) in Arabidopsis thaliana are transcriptionally upregulated upon gall formation. Mutations in the TIR family resulted in more susceptible reactions to the root pathogen. As target genes for the different pathways we have investigated the transcriptional regulation of selected transcriptional repressors (Aux/IAA) and transcription factors (ARF). As the TIR pathway controls auxin homeostasis via the upregulation of some auxin conjugate synthetases (GH3), the expression of selected GH3 genes was also investigated, showing in most cases upregulation. A double gh3 mutant showed also slightly higher susceptibility to P. brassicae infection, while all tested single mutants did not show any alteration in the clubroot phenotype. As targets for the ABP1-induced cell elongation the effect of potassium channel blockers on clubroot formation was investigated. Treatment with tetraethylammonium (TEA) resulted in less severe clubroot symptoms. This research provides evidence for the involvement of two auxin signaling pathways in Arabidopsis needed for the establishment of the root galls by P. brassicae

The Clubroot Pathogen (\u3ci\u3ePlasmodiophora brassicae\u3c/i\u3e) Influences Auxin Signaling to Regulate Auxin Homeostasis in Arabidopsis

The clubroot disease, caused by the obligate biotrophic protist Plasmodiophora brassicae, affects cruciferous crops worldwide. It is characterized by root swellings as symptoms, which are dependent on the alteration of auxin and cytokinin metabolism. Here, we describe that two different classes of auxin receptors, the TIR family and the auxin binding protein 1 (ABP1) in Arabidopsis thaliana are transcriptionally upregulated upon gall formation. Mutations in the TIR family resulted in more susceptible reactions to the root pathogen. As target genes for the different pathways we have investigated the transcriptional regulation of selected transcriptional repressors (Aux/IAA) and transcription factors (ARF). As the TIR pathway controls auxin homeostasis via the upregulation of some auxin conjugate synthetases (GH3), the expression of selected GH3 genes was also investigated, showing in most cases upregulation. A double gh3 mutant showed also slightly higher susceptibility to P. brassicae infection, while all tested single mutants did not show any alteration in the clubroot phenotype. As targets for the ABP1-induced cell elongation the effect of potassium channel blockers on clubroot formation was investigated. Treatment with tetraethylammonium (TEA) resulted in less severe clubroot symptoms. This research provides evidence for the involvement of two auxin signaling pathways in Arabidopsis needed for the establishment of the root galls by P. brassicae

Extracellular invertase is involved in the regulation of clubroot disease in Arabidopsis thaliana

Clubroot disease of Brassicaceae is caused by an obligatebiotrophic protist,Plasmodiophora brassicae. During root galldevelopment, a strong sink for assimilates is developed. Amongother genes involved in sucrose and starch synthesis and degra-dation, the increased expression of invertases has been observedin a microarray experiment, and invertase and invertase inhibitorexpression was confirmed using promoter::GUS lines ofArabi-dopsis thaliana. A functional approach demonstrates that inver-tases are important for gall development. Different transgeniclines expressing an invertase inhibitor under the control of tworoot-specific promoters,Pyk10andCrypticT80, which results inthe reduction of invertase activity, showed clearly reduced clu-broot symptoms in root tissue with highest promoter expression,whereas hypocotyl galls developed normally. These resultspresent the first evidence that invertases are important factorsduring gall development, most probably in supplying sugars tothe pathogen. In addition, root-specific repression of invertaseactivity could be used as a tool to reduce clubroot symptoms

Tolerance and cross-tolerance to neurocognitive effects of THC and alcohol in heavy cannabis users

and cross-tolerance to neurocognitive effects of THC and alcohol in heavy cannabis user