Project description:This project is aiming to identify specific root surface proteins from susceptible and resistant potato strains and identify those factors responsible for Spongospora subterranea zoospore binding.
Project description:We report the application of RNA- sequencing technology for high-throughput profiling of histone modifications in mammalian cellsor identification of expressed genes upon infection by Spongospora subterranea. Using RNA-sequencing (RNA-seq), 2058 differentially expressed genes (DEGs) were identified from two potato cultivars (tolerant and susceptible) in response to Sss infection. Analysis of the expression patterns of ten selected defense-response genes was carried out at two different stages of tuber growth using RT-qPCR to validate the RNA-seq data. Several defense related genes showed contrasting expression patterns between the tolerant and susceptible cultivars, including marker genes involved in the salicylic acid hormonal response pathway (StMRNA, StUDP and StWRKY6). Induction of six defense related genes (StWRKY6, StTOSB, StSN2, StLOX, StUDP and StSN1) persisted until harvest of the tubers, while three other genes (StNBS, StMRNA and StPRF) were highly up-regulated during the initial stages of disease development. The results of this study suggested that the tolerant potato cultivar employs quantitative resistance and salicylic acid pathway hormonal responses against tuber infection by Sss. The identified genes have the potential to be used in the development of molecular markers for selection of powdery scab resistant potato lines in marker assisted breeding programs.
Project description:Potato plants (cv. Russet Burbank) were grown as in vitro plantlets, and transplanted into 12-cm pots in Sunshine Mix #2 (peat/perlite mix) supplemented with slow release fertilizer (Osmocoat) in the greenhouse. The experiment was conducted in the summer of 2004 at Moscow, ID. Plantings were staggered to facilitate collection of volatiles and leaf samples during a short harvest window for all times of all treatments. Infectious Green Peach Aphids were raised on PLRV-infected potato plants; test plants were infected by placing 10 infectious aphids on a leaf in a clip cage for 48 h. The control plants for PLRV were similarly treated with aphids that had been raised on uninfected potato plants. A local isolate of PVYO was inoculated mechanically using purified virus (5 ìg ml-1) in buffer (50 mM Na2HPO4, 20 mM Na2SO3 pH 7.0) lightly rubbed onto a leaf previously dusted with carborundum. Control plants for PVY were treated in the same manner using buffer without PVY. The RNA samples were made from systemically affected leaves, excluding the actual leaves inoculated by aphids or that received the mechanical infection. Leaf volatiles were concurrently collected from equivalent plants; aliquots of frozen leaf samples were sent for metabolite analysis prior to RNA extraction. Leaf harvests were made 1, 3, 7, 14, and 28 d post-inoculation. Keywords: Direct comparison
Project description:Potato is one of the most important food crops for human consumption. The obligate biotrophic pathogen Spongospora subterranea infects potato roots and tubers, resulting in considerable loss of potato tuber yield and quality. A comprehensive understanding of how potato plants respond to S. subterranea infection is essential for the development of pathogen-resistant crops. Here we employed label-free proteomics and phosphoproteomics to quantify protein-level responses of the susceptible and resistant potato cultivars in response to S. subterranea. A total of 2669 proteins and 1498 phosphoproteins were quantified in the leaf samples of the different treatment groups. Following statistical analysis of the proteomic data, oxidoreductase activity, electron transfer, and photosynthesis were identified as significant processes that differentially changed upon infection specifically in the resistant cultivar and not in the susceptible cultivar. The phosphoproteomics results indicated increased activity of signal transduction and defence response functions in the resistant cultivar. In contrast, the majority of increased phosphoproteins in the susceptible cultivar were related to transporter activity and localisation. This study provides new insight into the molecular mechanisms involved in potato resistance to S. subterranea infection and has highlighted the critical roles of protein phosphorylation in the regulation of potato immune response.
Project description:For potato crops, host resistance is currently the most effective and sustainable tool to manage potato root and tuber diseases caused by the plasmodiophorid, Spongospora subterranea. Arguably, zoospore root attachment is the most critical phase of the pathogen infection, however, the mechanisms underlying zoospore root attachment remains unknown. This study investigated the potential role of root cell wall surface polysaccharides and proteins in zoospore root attachment in resistant and susceptible potato cultivars. We first compared the effects of enzymatic removal of root cell wall proteins, N-linked glycans or polysaccharides on S. subterranea attachment to root tissue of resistant and susceptible potato cultivars. Subsequently, mass spectrometry analysis of peptides released by trypsin shaving (TS) of root segments identified 1235 proteins, of which 262 were differentially abundant between the resistant and susceptible cultivars. In particular, proteins associated with glutathione metabolism and lignin biosynthesis were more abundant in the resistant cultivar. Comparison with whole-root proteomic analysis of the same resistant and susceptible cultivars led to identification of 226 proteins unique to the TS dataset, of which 188 were significantly different between cultivars. Among these, the pathogen defence-related cell wall protein stem 28 kDa glycoprotein and two major latex proteins were significantly less abundant in the resistant cultivar compared to the susceptible cultivar. A further major latex protein was detected at reduced levels in the resistant cultivar in both TS and whole-root proteomic datasets. In contrast, in the TS-specific dataset, three glutathione S-transferase proteins were more abundant in the resistant cultivar, while the protein glucan endo-1,3-beta-glucosidase was significantly increased in both the TS and whole-root datasets. These results imply a particular role of major latex proteins and glucan endo-1,3-beta-glucosidase in the regulation of host susceptibility to S. subterranea.
Project description:Two potato cultivars, Russet Burbank and Bionta, were inoculated with three different endophytes containing different AHL types. The impact of the endophytes to the different cultivars was measured by gene expression analysis with a customized microarray