Project description:Xanthomonas campestris pathovar campestris causes black rot, a vascular disease on cruciferous plants, including Arabidopsis thaliana. The gene XC1553 from X. campestris pv. campestris strain 8004 encodes a protein containing leucine-rich repeats (LRRs) and appears to be restricted to strains of X. campestris pv. campestris. LRRs are found in a number of type III-secreted effectors in plant and animal pathogens. These prompted us to investigate the role of the XC1553 gene in the interaction between X. campestris pv. campestris and A. thaliana. Translocation assays using the hypersensitive-reaction-inducing domain of X. campestris pv. campestris AvrBs1 as a reporter revealed that XC1553 is a type III effector. Infiltration of Arabidopsis leaf mesophyll with bacterial suspensions showed no differences between the wild-type strain and an XC1553 gene mutant; both strains induced disease symptoms on Kashmir and Col-0 ecotypes. However, a clear difference was observed when bacteria were introduced into the vascular system by piercing the central vein of leaves. In this case, the wild-type strain 8004 caused disease on the Kashmir ecotype, but not on ecotype Col-0; the XC1553 gene mutant became virulent on the Col-0 ecotype and still induced disease on the Kashmir ecotype. Altogether, these data show that the XC1553 gene, which was renamed avrAC(Xcc8004), functions as an avirulence gene whose product seems to be recognized in vascular tissues.
Project description:Autopolyploidy is a process whereby the chromosome set is multiplied and it is a common phenomenon in angiosperms. Autopolyploidy is thought to be an important evolutionary force that has led to the formation of new plant species. Despite its relevance, the consequences of autopolyploidy in plant metabolism are poorly understood. This study compares the metabolic profiles of natural diploids and artificial autotetraploids of Arabidopsis thaliana Col-0. Different physiological parameters are compared between diploids and autotetraploids using nuclear magnetic resonance (NMR), elemental analysis (carbon:nitrogen balance) and quantitative real-time PCR (qRT-PCR). The main difference between diploid and autotetraploid A. thaliana Col-0 is observed in the concentration of metabolites related to the tricarboxylic acid cycle (TCA) and ?-amino butyric acid (GABA) shunt, as shown by multivariate statistical analysis of NMR spectra. qRT-PCR shows that genes related to the TCA and GABA shunt are also differentially expressed between diploids and autotetraploids following similar trends as their corresponding metabolites. Solid evidence is presented to demonstrate that autopolyploidy influences core plant metabolic processes.
Project description:Differentially regulated genes in rosette leaves and roots of hydroponically grown Arabidopsis thaliana Col-0 and nrt1.5-5 mutant plants were identified by microarray analyses. Overall design: Arabidopsis thaliana Col-0 wild type and nrt1.5-5 (GABI_347B03) mutant plants were grown hydroponically under short day conditions (10 h/14 h light/dark) in nitrogen limiting conditions. From nine weeks old plants rosette leaves no. 13 and younger and roots were separately harvested for transcriptome analysis.
Project description:Many Arabidopsis thaliana accession show sensitvity to the air pollutant ozone, including the accession Cvi-0 from the Cape Verde Islands. To understand and assist in genetic mapping of loci causing the ozone sensitvity of Cvi-0, transcript profiling was performed in Cvi-0, the tolerant Col-0, and a near isogenic line (Col-S) where ozone sensitivity was introgressesed from Cvi-0 to Col-0 through eight rounds of backcrossing. Overall design: The near isogenic line Col-S and its parents Col-0 and Cvi-0 were grown for three weeks and treated with 350 ppb ozone for two hours. The whole rosettas were harvested from controls and and ozone treated plants. Three separate biological repeats used for RNA-seq analysis.
Project description:In this experiment we evaluate the transcriptional response to beet cyst nematode infection in wild-type (Col-0) and a upl3 knocked-down Arabidopsis thaliana. The data indicates that the upl3 knock-down alone does not induce a strong transcriptional regulation in the plant. However, the interaction of the mutation and infection by H. schachtii results in a strong transcriptional differential regulation, likely involving the plant’s immune responses. Samples were taken from whole root systems of 14 day-old seedlings (0 days post-infection) and mock or H. schahtii-infected 21 day-old seedlings (7 days post-infection). Each sample contained at least 18 plants and 4 biological replicates of each sample were collected.