ABSTRACT: The potato cyst nematodes (PCN), Globodera pallida and Globodera rostochiensis, are important parasites of potato. PCN have complex, biotrophic interactions with their hosts that involve gene expression changes in both the nematode and the host plant. The aim of this study is to determine key genes that are differentially expressed in Globodera pallida life cycle stages and during the initiation of the feeding site in susceptible or partially resistant potato genotypes. For this purpose, two microarray experiments were designed: i) a comparison of eggs, infective second stage juveniles (J2) and sedentary parasitic stage J2s (SJ2); ii) a comparison of SJ2 at eight days after inoculation (DAI) in the susceptible cultivar (Desiree) and two partially resistant lines. The data set in this submission came from experiment (I). The results show differential expression of G. pallida genes during the stages studied, including previously characterized effectors. Also, a large number of genes changed their expression between the SJ2 in the susceptible cultivar compared to those infecting partially resistant lines; the number of genes with modified expression were smaller when two partially resistant lines were compared. Additionally, a histopathological study was performed at several time points (7, 14 and 30 DAI) showing the similarities between both partially resistant lines with a delay and degeneration in the formation of the syncytia in comparison to the susceptible cultivar. Females at 30 DAI in partially resistant lines showed a delay in their development in comparison to the susceptible cultivar.
Project description:The potato cyst nematodes (PCN), Globodera pallida and Globodera rostochiensis, are important parasites of potato. PCN have complex, biotrophic interactions with their hosts that involve gene expression changes in both the nematode and the host plant. The aim of this study is to determine key genes that are differentially expressed in Globodera pallida life cycle stages and during the initiation of the feeding site in susceptible or partially resistant potato genotypes. For this purpose, two microarray experiments were designed: i) a comparison of eggs, infective second stage juveniles (J2) and sedentary parasitic stage J2s (SJ2); ii) a comparison of SJ2 at eight days after inoculation (DAI) in the susceptible cultivar (Desiree) and two partially resistant lines. The data set in this submission came from experiment (ii). (Experiment (I) has also been deposited in ArrayExpress under accession E-MTAB-999). The results show differential expression of G. pallida genes during the stages studied, including previously characterized effectors. Also, a large number of genes changed their expression between the SJ2 in the susceptible cultivar compared to those infecting partially resistant lines; the number of genes with modified expression were smaller when two partially resistant lines were compared. Additionally, a histopathological study was performed at several time points (7, 14 and 30 DAI) showing the similarities between both partially resistant lines with a delay and degeneration in the formation of the syncytia in comparison to the susceptible cultivar. Females at 30 DAI in partially resistant lines showed a delay in their development in comparison to the susceptible cultivar.
Project description:The potato powdery scab agent Spongospora subterranea causes damage on the skin of tubers and induces root gall formation, precipitating considerable yield and quality losses. Currently, there are no effective chemical treatments for the control of powdery scabs. Understanding the inducible defence responses in roots of potato plants in the resistant and susceptible host environment, particularly during colonisation of the root by S. subterranea is required for the breeding of novel resistant cultivars. Here, we integrated transcriptomics, proteomics and metabolomics datasets to uncover the mechanisms underlying of the potato resistance to powdery scab. This multi-omics approach identified upregulation of glutathione metabolism at the levels of RNA, protein and metabolite in the resistant cultivar but not in the susceptible cultivar. Upregulation of the lignin metabolic process was also specific to in the resistant cultivar at the transcriptome level. In addition, Tthe inositol phosphate pathway was differentially expressed between two cultivars in response to S. subterranea infection, where it was upregulated in the susceptible cultivar but downregulated in the resistant cultivar. We provide, for the first time, large-scale multi-omics data of Spongospora-potato interaction, thereby suggesting the signaling role of glutathione metabolism in the potato resistance against powdery scab
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:As part of the Globodera pallida (potato cyst nematode) genome project weare profiling the transcriptome of the parasite across its life cycle usingRNA-Seq. . This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
Project description:Switchgrass (Panicum virgatum) can be infected by the rust pathogen (Puccinia novopanici) resulting in lowering biomass yields and quality. Here, two cultivars with divergent rust resistance were used to evaluate the dynamic changes in proteomes following rust inoculation. Label-free quantitative proteomics was conducted on leaf extracts harvested from a susceptible cultivar Summer at 7, 11, and 18 DAI, and leaves collected at 18 DAI from controls and infected plants of the more resistant cultivar Kanlow.
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:Sets of seven 2-week old potato plants carrying the nematode resistance gene H1, grown from tuber ‘chits’ in sandy loam at a constant temperature of 20 ºC and a light cycle of 16 hour light/8 hour dark, were each inoculated in the roots evenly with 2000 juveniles of the virulent potato cyst nematode Globodera pallida, or with the avirulent G. rostochiensis pathotype Ro1, or with water. Plants were manually watered throughout the duration of the experiment. 5, 17 and 33 days after inoculation, the roots were carefully washed and root tissue samples were individually flash-frozen in liquid nitrogen and stored at –80 ºC. Total RNA isolations were performed using the Qiagen RNeasy kit. All samples were treated with DNase. The experiment was replicated twice. Keywords: Direct comparison
Project description:Plant-parasitic nematodes (PPN) need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest (including desiccation, cryopreservation, hatching inhibition and dauer stages) are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) are frequently in a dessicated state unhatched nematodes within the egg dispersal unit inside the cyst. Long term survival seems to be associated primarily with species that have a very restricted host range which requires surviving unhatched in the absence of the host for extended periods of time. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G.pallida to hydration and following exposure to tomato root diffusate using microarray gene expression analysis from a broad set of genes. Surprisingly, many unique genes were activated in the population of diapaused eggs. Transport activity was activated in both quiescent and diapaused eggs; however, the transport function genes were very different between them. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long term survival.
Project description:Potato virus YNTN (PVYNTN), causing potato tuber ring necrosis disease, dramatically lowers the quantity and the quality of the potato yield all over the world. While cultivar Igor is one of the most susceptible cultivars, developing severe disease symptoms on plants as well as on tubers, cv. Sante is resistant and thus not affected by the virus. Finding genes differentially expressed in the early response to infection, when the host response is more defense- than infection- related, could improve our understanding of the potato - PVYNTN interaction. Moreover, the differences in the response of the sensitive and resistant cultivar can pinpoint the genes involved in differential sensitivity of the cultivars. Differential gene expression in the early response of potato cvs. Igor and Sante to PVYNTN infection was studied using potato TIGR cDNA-microarrays. Expression was compared between mock inoculated and virus infected plants 0.5 and 12 hours after inoculation.