Project description:Xylem sap of young cabbage plantlets was recovered from root pressure exudation and used as a growth medium for the vascular pathogen Xanthomonas campestris pv campestris, the causative agent of the black rot of Brassicaceae.
Project description:The fungal pathogen Fusarium moniliforme causes ear rot in maize. Ear rot in maize is a destructive disease globally caused by Fusarium moniliforme , due to decrease of grain yield and increase of risks in raising livestock by mycotoxins production. Plants have developed various defense pathways to cope with pathogens. We used microarrays to detail the global programme of gene expression during the infection process of Fusarium moniliforme in its host plant to get insights into the defense programs and the host processes potentially involved in plant defense against this pathogen.
Project description:The soft rot pathogen Janthinobacterium agaricidamnosum causes devastating damage to button mushrooms (Agaricus bisporus), one of the most cultivated and commercially relevant mushrooms. We previously discovered that this pathogen releases the membrane-disrupting lipopeptide jagaricin. This bacterial toxin, however, could not solely explain the rapid decay of mushroom fruiting bodies, indicating that J. agaricidamnosum implements a more sophisticated infection strategy. In this study, we show that secretion systems play a crucial role in soft rot disease. By mining the genome of J. agaricidamnosum, we identified gene clusters encoding a type I (T1SS), a type II (T2SS), a type III (T3SS), and two type VI secretion systems (T6SS). Through a combination of knockout studies and bioassays, we found that the T2SS and T3SS of J. agaricidamnosum are required for soft rot disease. Furthermore, comparative secretome analysis and activity-guided fractionation identified a number of secreted lytic enzymes responsible for mushroom damage. Our findings regarding the contribution of secretion systems to the disease process expand the current knowledge of bacterial soft rot pathogens and represent a significant stride towards identifying targets for their disarmament with secretion system inhibitors.
Project description:The oomycete pathogen Phytophthora sojae causes root rot of soybean. During infection, the pathogen is thought to deliver dozens, if not hundreds, of effector proteins into the host to manipulate intracellular systems. Although these pathogen proteins often exhibit similar N-terminal delivery domains, the remaining effector region is rarely homologous to known protein domains, making it difficult to predict its biochemical function during infection. As a complement to studies in the natural host, Saccharomyces cerevisiae has been successfully used as a model system to explore the biochemical function of individual pathogen effectors. The presumption is that many effectors target conserved eukaryotic pathways in the host and consequently the expression of effectors in yeast will confer corresponding phenotypes. Indeed, putative effector functions identified using yeast functional genomic approaches have subsequently been validated in the natural host. Over-expression of the Phytophthora sojae effector Avh172 (PsAvh172) inhibits the growth of Saccharomyces cerevisiae, suggesting that the effector targets a biological pathway conserved with plants. In this study, the transcriptomes of yeast expressing PsAvh172 or an empty vector were compared to examine the global transcriptional response, in hopes of discerning the effectors biochemical target.