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Norwich, United Kingdom

Bos J.I.B.,John Innes Center | Bos J.I.B.,Scottish Crop Research Institute | Prince D.,John Innes Center | Pitino M.,John Innes Center | And 3 more authors.
PLoS Genetics

Aphids are amongst the most devastating sap-feeding insects of plants. Like most plant parasites, aphids require intimate associations with their host plants to gain access to nutrients. Aphid feeding induces responses such as clogging of phloem sieve elements and callose formation, which are suppressed by unknown molecules, probably proteins, in aphid saliva. Therefore, it is likely that aphids, like plant pathogens, deliver proteins (effectors) inside their hosts to modulate host cell processes, suppress plant defenses, and promote infestation. We exploited publicly available aphid salivary gland expressed sequence tags (ESTs) to apply a functional genomics approach for identification of candidate effectors from Myzus persicae (green peach aphid), based on common features of plant pathogen effectors. A total of 48 effector candidates were identified, cloned, and subjected to transient overexpression in Nicotiana benthamiana to assay for elicitation of a phenotype, suppression of the Pathogen-Associated Molecular Pattern (PAMP)-mediated oxidative burst, and effects on aphid reproductive performance. We identified one candidate effector, Mp10, which specifically induced chlorosis and local cell death in N. benthamiana and conferred avirulence to recombinant Potato virus X (PVX) expressing Mp10, PVX-Mp10, in N. tabacum, indicating that this protein may trigger plant defenses. The ubiquitin-ligase associated protein SGT1 was required for the Mp10-mediated chlorosis response in N. benthamiana. Mp10 also suppressed the oxidative burst induced by flg22, but not by chitin. Aphid fecundity assays revealed that in planta overexpression of Mp10 and Mp42 reduced aphid fecundity, whereas another effector candidate, MpC002, enhanced aphid fecundity. Thus, these results suggest that, although Mp10 suppresses flg22-triggered immunity, it triggers a defense response, resulting in an overall decrease in aphid performance in the fecundity assays. Overall, we identified aphid salivary proteins that share features with plant pathogen effectors and therefore may function as aphid effectors by perturbing host cellular processes. © 2010 Bos et al. Source

Wulft B.B.H.,John Innes Center | Moscou M.J.,The Sainsbury Laboratory
Frontiers in Plant Science

The domestication of wheat in the Fertile Crescent 10,000 years ago led to a genetic bottleneck. Modern agriculture has further narrowed the genetic base by introducing extreme levels of uniformity on a vast spatial and temporal scale. This reduction in genetic complexity renders the crop vulnerable to new and emerging pests and pathogens. The wild relatives of wheat represent an important source of genetic variation for disease resistance. For nearly a century farmers, breeders, and cytogeneticists have sought to access this variation for crop improvement. Several barriers restricting interspecies hybridization and introgression have been overcome, providing the opportunity to tap an extensive reservoir of genetic diversity. Resistance has been introgressed into wheat from at least 52 species from 13 genera, demonstrating the remarkable plasticity of the wheat genome and the importance of such natural variation in wheat breeding. Two main problems hinder the effective deployment of introgressed resistance genes for crop improvement: (1) the simultaneous introduction of genetically linked deleterious traits and (2) the rapid breakdown of resistance when deployed individually. In this review, we discuss how recent advances in molecular genomics are providing new opportunities to overcome these problems. © 2014 Wulff and Moscou. Source

Gimenez-Ibanez S.,The Sainsbury Laboratory | Rathjen J.P.,Australian National University
Microbes and Infection

Incredible progress has been made over the last 20 years in understanding the components and mechanisms governing plant innate immunity. The most important discoveries concern pathogen recognition mechanisms, which divide perception of conserved elicitors at the cell periphery, and recognition of variable elicitors within the host cytoplasm. The underlying mechanisms of immunity post elicitation are complex and poorly defined. This review highlights emergent themes in plant-microbe interactions with a particular focus on the plant immune responses against infection by the bacterium Pseudomonas syringae. © 2010 Elsevier Masson SAS. All rights reserved. Source

Bogdanove A.J.,Iowa State University | Schornack S.,The Sainsbury Laboratory | Lahaye T.,Ludwig Maximilians University of Munich
Current Opinion in Plant Biology

Transcription activator like effectors (TALEs) are injected via the type III secretion pathway of many plant pathogenic Xanthomonas spp. into plant cells where they contribute to disease or trigger resistance by binding to DNA and turning on TALE-specific host genes. Advances in our understanding of TALEs and their targets have yielded new models for pathogen recognition and defense. Similarly, we have gained insight into plant molecules and processes that can be co-opted to promote infection. Recent elucidation of the basis for specificity in DNA binding by TALEs expedites further discovery and opens the door to biotechnological applications. This article reviews the most significant findings in TALE research, with a focus on recent advances, and discusses future prospects including pressing questions yet to be answered. © 2010 Elsevier Ltd. Source

Agency: Cordis | Branch: H2020 | Program: MSCA-IF-EF-ST | Phase: MSCA-IF-2014-EF | Award Amount: 183.45K | Year: 2016

Plants are rich sources of nutrients and water for diverse microbial communities. Some of these communities evolved parasitism as a strategy to access plant nutrients, with devastating results for crops. Plants are protected from infection by a waxy cuticular layer above the walls of epidermal cells. Would-be pathogens breaching this barrier, or entering via stomata, encounter an active plant immune system that specifically recognizes pathogens. Breaching leads to the deployment of two synergistic pathways that orchestrate immune responses. The first relies on the detection of pathogen-associated molecular patterns (PAMPs) and culminates in pattern-triggered immunity (PTI). When the first is circumvented a second array of responses takes place known as effector triggered immunity (ETI). In ETI, host factors known as R proteins recognize pathogen effectors, an event which is accompanied by the execution of a unique programmed cell death (PCD) type known as the hypersensitive response (HR). Although the initiator of the HR-PCD is known to depend on the formation of an effector-R complex, the downstream molecular events remain elusive. Previous results showed that particular proteases known as metacaspases (MCs) modulate HR-PCD, highlighting the importance of proteolysis and proteome rearrangements for HR-PCD modulation. I will attempt to shed light on the rearrangements of the HR-PCD proteome landscape, by studying processes that control it: selective RNA decapping and translation and proteolytic events, in a highly temporal manner using systematic approaches and reverse genetics. This project is expected to elucidate the importance of these processes and provide a detailed analysis of mRNA and protein level rearrangements during HR-PCD. In addition, this project will suggest strategies for enhancement of plant immunity against pathogens, which is urgently needed to sustain food security considering the ever growing earths population.

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