1,720,957 research outputs found
Investigation of natural RIN4 variants reveals a motif crucial for function and provides an opportunity to broaden NLR regulation specificity
No full textMultiple bacterial effectors target RPM1-INTERACTING PROTEIN4 (RIN4), the biochemical modifications of which are recognized by several plant nucleotide-binding and leucine-rich repeat immune receptor (NLR) proteins. Recently, a comparative study of Arabidopsis and apple (Malus domestica) RIN4s revealed that the RIN4 specificity motif (RSM) is critical for NLR regulation. Here, we investigated the extent to which the RSM contributes to the functions of natural RIN4 variants. Functional analysis of 33 natural RIN4 variants from 28 plant species showed that the RSM is generally required yet sometimes dispensable for the RIN4-mediated suppression of NLR auto-activity or effector-triggered NLR activation. Association analysis of the sequences and fire blight resistance gene originating from Malus x robusta 5 (FB_MR5) activation functions of the natural RIN4 variants revealed H167 to be an indispensable residue for RIN4 function in the regulation of NLRs. None of the tested natural RIN4 variants could suppress RESISTANCE TO PSEUDOMONAS SYRINGAE PV. MACULICOLA1 (RPM1) auto-activity and activate FB_MR5. To engineer RIN4 to carry broader NLR compatibility, we generated chimeric RIN4 proteins, several of which could regulate RPM1, RESISTANT TO PSEUDOMONAS SYRINGAE2 (RPS2), and FB_MR5. We propose that the intrinsically disordered nature of RIN4 provides a flexible platform to broaden pathogen recognition specificity by establishing compatibility with otherwise incompatible NLRs.11Nsciescopu
Host adaptation and microbial competition drive Ralstonia solanacearum phylotype I evolution in the Republic of Korea
No full textBacterial wilt caused by the Ralstonia solanacearum species complex (RSSC) threatens the cultivation of important crops worldwide. We sequenced 30 RSSC phylotype I (R. pseudosolanacearum) strains isolated from pepper (Capsicum annuum) and tomato (Solanum lycopersicum) across the Republic of Korea. These isolates span the diversity of phylotype I, have extensive effector repertoires and are subject to frequent recombination. Recombination hotspots among South Korean phylotype I isolates include multiple predicted contact-dependent inhibition loci, suggesting that microbial competition plays a significant role in Ralstonia evolution. Rapid diversification of secreted effectors presents challenges for the development of disease-resistant plant varieties. We identified potential targets for disease resistance breeding by testing for allele-specific host recognition of T3Es present among South Korean phyloype I isolates. The integration of pathogen population genomics and molecular plant pathology contributes to the development of location-specific disease control and development of plant cultivars with durable resistance to relevant threats.11Ysciescopu
Molecular analysis of plant innate immunity triggered by secreted effectors from bacterial and fungal pathogens of apple : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Plant Science, Institute of Agriculture and Environment, Massey University, New Zealand
No full textIn comparison to animals, plants do not have a dedicated immune system
with mobile immune cells to protect themselves. Instead they rely on the innate immunity of each cell. Plant immunity branches into two classical layers: PTI (PAMP-triggered immunity) and ETI (Effector-triggered immunity). PTI detects the conserved molecular patterns (PAMPs) associated with pathogens and often can be overcome by pathogens translocating effector molecules into plant cells to inhibit the PTI. ETI, in turn, relies on intracellular receptors that can specifically recognize effectors or their activity and activate a rapid and robust response.
The research presented in this thesis is focused on two pathogens of apple
plants: the bacterial pathogen Erwinia amylovora (the causal agent of fire blight) and fungal pathogen Venturia inaequalis (the causal agent of apple scab disease). As both bacterial and fungal pathogens deliver effector molecules in order to promote their virulence, ETI engineering is a promising universal strategy to control these pathogens.
In Chapter 3, the main aim was to elucidate the requirements and precise
mechanism of how an important effector of E. amylovora, AvrRpt2, is recognized by the MR5 disease resistance (R) protein, derived from a hybrid apple Malus x robusta 5. I identified that a fragment of the guardee apple protein RIN4 was required and sufficient and required for MR5 activation. I further identified crucial amino acid residues responsible for this activation. Interestingly, cognate residues in RIN4 guardee homolog from Arabidopsis thaliana are responsible for suppression of the autoactivity of R protein RPS2. These findings led to the proposal of a novel hypothesis for evolutionary guardee adaption to the pool of R proteins present in plants.
In Chapter 4, the main focus was to apply newly acquired whole-genome
sequencing data of V. inaequalis for identifying the previously mapped AvrRvi8
effector, as well as several novel effectors predicted in silico. The sequences of
these effectors were validated by amplification and resequencing of candidate
genes from V. inaequalis cDNA. Further functional analysis of the selected gene candidates was performed. In addition, a library of constructs for generating V. inaequalis knock-out strains was prepared for future work.
The findings from this thesis expected to be useful for breeders of apple to battle two economically important pathogens devastating the industry. Deployment of the MR5 system in apples should facilitate fire blight resistance in pipfruit and offers the opportunity for further engineering of MR5 to detect other pathogens. Furthermore, the effector library developed for V. inaequalis offers a novel tool for studying both virulence and avirulence mechanisms present in the applescab pathosystem. It is envisaged that further effector research will elucidate authentic targets critical for resistance development in apple
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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