scholarly journals Sensitivity genes in wheat and corresponding effector genes in necrotrophs exhibiting inverse gene-for-gene relationship

2021 ◽  
Author(s):  
Pushpendra Kumar Gupta ◽  
Neeraj Kumar Vasistha ◽  
Pawan Kumar Singh
Keyword(s):  
Bipolaris Sorokiniana ◽  
Relevant Information ◽  
Tan Spot ◽  
Future Research ◽  
Disease Symptoms ◽  
Septoria Nodorum Blotch ◽  
Effector Genes ◽  
Necrotrophic Effectors ◽  
S Genes ◽  
Gene For Gene

Abstract In wheat, genes for resistance (R) as well as susceptibility (S) are now known for several diseases. The S genes also include sensitivity genes like Tsn1 in wheat. R genes follow a gene-for-gene (GFG) relationship and generally involve biotrophs and S genes particularly sensitivity genes, follow an inverse gene-for-gene relationship (IGFG), generally involving necrotroph or hemi-biotroph pathogens. The toxin (virulence factor) genes of the pathogen and the corresponding sensitivity genes have been described in some detail for the following three pathogens: (i) Paratagonospora nodorum (causing Septoria nodorum blotch or SNB); (ii) Pyrenophora tritici-repentis (tan spot) and (iii) Bipolaris sorokiniana (spot blotch). These and some other pathogens produce several necrotrophic effectors (NEs), which interact directly or indirectly with the products of S genes in the host and produce disease symptoms like necrosis and/or chlorosis. In this article we present a critical review of all the relevant information about the interactions between NEs of the above three pathogens and the corresponding S genes in wheat. The gaps in knowledge and possibilities for future research are also discussed.

scholarly journals Parastagonospora nodorum and Related Species in Western Canada: Genetic Variability and Effector Genes

2020 ◽  
Vol 110 (12) ◽  
pp. 1946-1958
Author(s):  
Mohamed Hafez ◽  
Ryan Gourlie ◽  
Therese Despins ◽  
Thomas K. Turkington ◽  
Timothy L. Friesen ◽  
...  
Keyword(s):  
Evolutionary Relationship ◽  
Haplotype Network ◽  
Bipolaris Sorokiniana ◽  
Western Canada ◽  
Pyrenophora Tritici Repentis ◽  
Septoria Nodorum Blotch ◽  
Effector Genes ◽  
Parastagonospora Nodorum ◽  
Almost All ◽  
Necrotrophic Effectors

Parastagonospora nodorum is an important fungal pathogen that causes Septoria nodorum blotch (SNB) in wheat. This pathogen produces several necrotrophic effectors that act as virulence factors; three have been cloned, SnToxA, SnTox1, and SnTox3. In this study, P. nodorum and its sister species P. avenaria f. tritici (Pat1) were isolated from wheat node and grain samples collected from distanced sites in western Canada during 2018. The presence of effector genes and associated haplotypes were determined by PCR and sequence analysis. An internal transcribed spacer-restriction fragment length polymorphism test was developed to distinguish between leaf spotting pathogens (P. nodorum, Pat1, Pyrenophora tritici-repentis, and Bipolaris sorokiniana). P. nodorum was mainly recovered from wheat nodes and to a lesser extent from the grains, while Pat1 was exclusively isolated from grain samples. The effector genes were present in almost all P. nodorum isolates, with the ToxA haplotype 5 (H5) being most prevalent, while a novel ToxA haplotype (denoted here H21) is reported for the first time. In Pat1, only combinations of SnTox1 and SnTox3 genes were present. A ToxA haplotype network was also constructed to assess the evolutionary relationship among globally found haplotypes to date. Finally, cultivars representing wheat development in Canada for the last century were tested for sensitivity to Sn-effectors and to the presence of Tsn1, the ToxA sensitivity gene. Of tested cultivars, 32.9 and 56.9% were sensitive to SnTox1 and SnTox3, respectively, and Tsn1 was present in 59% of the cultivars. In conclusion, P. nodorum and Pat1 were prevalent wheat pathogens in Canada with a potential tissue-specific colonization capacity, while producing necrotrophic effectors to which wheat is sensitive.

scholarly journals SnToxA, SnTox1 and SnTox3 originated in Parastagonospora nodorum in the Fertile Crescent

2020 ◽  
Author(s):  
Fariba Ghaderi ◽  
Bahram Sharifnabi ◽  
Mohammad Javan-Nikkhah ◽  
Patrick C. Brunner ◽  
Bruce A. McDonald
Keyword(s):  
Spatial Scales ◽  
Bipolaris Sorokiniana ◽  
Center Of Origin ◽  
Pyrenophora Tritici Repentis ◽  
Effector Genes ◽  
A Genome ◽  
Fertile Crescent ◽  
Genes Encoding ◽  
Parastagonospora Nodorum ◽  
Necrotrophic Effectors

ABSTRACTThe center of origin of the globally distributed wheat pathogen Parastagnospora nodorum has remained uncertain because only a small number of isolates from the Fertile Crescent, a region in the Middle East where wheat was domesticated from wild grasses, were included in earlier population genetic and phylogeographic studies. We isolated and genetically analyzed 193 P. nodorum strains from three naturally infected wheat fields distributed across Iran, a country located within the Fertile Crescent, using eleven neutral microsatellite loci. Compared to previous studies that included populations from North America, Europe, Africa, Australia and China, the populations from Iran had the highest genetic diversity globally and also exhibited greater population structure over smaller spatial scales, patterns typically associated with a species’ center of origin. Genes encoding the necrotrophic effectors SnToxA, SnTox1 and SnTox3 were found at a high frequency in the Iranian population. By sequencing 96 randomly chosen Iranian strains, we detected new alleles for all three effector genes. Analyses of allele diversity showed that all three effector genes had higher diversity in Iran than in any population included in previous studies, with Iran acting as a hub for the effector diversity that was found in other global populations. Taken together, these findings support the hypothesis that P. nodorum originated either within or nearby the Fertile Crescent with a genome that already encoded all three necrotrophic effectors during its emergence as a pathogen on wheat. Our findings also suggest that P. nodorum was the original source of the ToxA genes discovered in the wheat pathogens Phaeosphaeria avenaria f. sp. tritici 1, Pyrenophora tritici-repentis and Bipolaris sorokiniana.

scholarly journals Sensitivity to three Parastagonospora nodorum necrotrophic effectors in current Australian wheat cultivars and the presence of further fungal effectors

2014 ◽  
Vol 65 (2) ◽  
pp. 150 ◽  
Author(s):  
Kar-Chun Tan ◽  
Ormonde D. C. Waters ◽  
Kasia Rybak ◽  
Eva Antoni ◽  
Eiko Furuki ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Gene Interactions ◽  
Wheat Cultivars ◽  
Septoria Nodorum Blotch ◽  
Effector Genes ◽  
Australian Wheat ◽  
Parastagonospora Nodorum ◽  
Necrotrophic Effector ◽  
Necrotrophic Effectors ◽  
Western Australian

Parastagonospora nodorum is a major fungal pathogen of wheat in Australia, causing septoria nodorum blotch (SNB). Virulence of P. nodorum is quantitative and depends largely on multiple effector–host sensitivity gene interactions. The pathogen utilises a series of proteinaceous, necrotrophic effectors to facilitate disease development on wheat cultivars that possess appropriate dominant sensitivity loci. Thus far, three necrotrophic effector genes have been cloned. Proteins derived from these genes were used to identify wheat cultivars that confer effector sensitivity. The goal of this study was to determine whether effector sensitivity could be used to enhance breeding for SNB resistance. We have demonstrated that SnTox1 effector sensitivity is common in current commercial Western Australian wheat cultivars. Thirty-three of 46 cultivars showed evidence of sensitivity to SnTox1. Of these, 19 showed moderate or strong chlorotic/necrotic responses to SnTox1. Thirteen were completely insensitive to SnTox1. Disease susceptibility was most closely associated with SnTox3 sensitivity. We have also identified biochemical evidence of a novel chlorosis-inducing protein or proteins in P. nodorum culture filtrates unmasked in strains that lack expression of ToxA, SnTox1 and SnTox3 activities.

scholarly journals A wheat chromosome 5AL region confers seedling resistance to both tan spot and Septoria nodorum blotch in two mapping populations

2019 ◽  
Vol 7 (6) ◽  
pp. 809-818 ◽  
Author(s):  
Wenjing Hu ◽  
Xinyao He ◽  
Susanne Dreisigacker ◽  
Carolina P. Sansaloni ◽  
Philomin Juliana ◽  
...  
Keyword(s):  
Wheat Chromosome ◽  
Tan Spot ◽  
Septoria Nodorum ◽  
Seedling Resistance ◽  
Septoria Nodorum Blotch ◽  
Mapping Populations

Making one-sided exercise decisions: The influence of exercise-related cognitive errors

2016 ◽  
Vol 23 (9) ◽  
pp. 1240-1249 ◽  
Author(s):  
Sean R Locke ◽  
Lawrence R Brawley
Keyword(s):  
Decision Making ◽  
Information Processing ◽  
Relevant Information ◽  
Future Research ◽  
Cognitive Errors ◽  
Online Questionnaire ◽  
Cognitive Error ◽  
Biased Processing

Exercise-related cognitive errors reflect biased processing of exercise-relevant information. The purpose of this study was to examine whether differences existed between individuals reporting low and high exercise-related cognitive errors on information processed about a relevant exercise decision-making situation. In all, 138 adults completed an online questionnaire. The high exercise-related cognitive error group primarily focused on negative content about the situation compared to the low exercise-related cognitive error group who focused on both positive and negative content. The high exercise-related cognitive error group displayed biased processing of exercise information, as suggested by the cognitive errors model. Future research should examine whether biasing information processing caused by exercise-related cognitive errors can be modified and attenuated.

Cryptocurrency bubble risk and the FOMC announcements during COVID-19 black swan event

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anis Jarboui ◽  
Emna Mnif
Keyword(s):  
Federal Reserve ◽  
Abnormal Returns ◽  
Relevant Information ◽  
Future Research ◽  
Open Market ◽  
Predictive Capacity ◽  
Federal Open Market Committee ◽  
Content Type ◽  
Cumulative Abnormal Returns ◽  
Practical Implications

Purpose After the COVID-19 outbreak, the Federal Reserve has undertaken several monetary policies to alleviate the pandemic consequences on the markets. This paper aims to evaluate the effects of the Federal Reserve monetary policy on the cryptocurrency dynamics during the COVID19 pandemic. Design/methodology/approach We examine the response and feedback effects via an event study methodology. For this purpose, abnormal returns (AR) and cumulative abnormal returns (CARs) around the first FOMC (Federal Open Market Committee) announcement related to the COVID-19 pandemic for the top five cryptocurrencies are explored. We, further investigate the effect of the eight FOMC statement announcements during the COVID19 pandemic on these cryptocurrencies (Bitcoin, Ethereum, Tether, Litecoin, and Ripple). In the above-mentioned crypto-currency markets, we investigate the presence of bubbles by using the PSY test. We then examine the concordance of the dates of these bubbles with the dates of the FOMC announcements. Findings The empirical results show that the first FOMC event has a negative significant effect after 4 days of the announcement date for all studied cryptocurrencies except Tether. The results also indicate that cumulative abnormal returns are significant during the event windows of (−3,8), (−3,9), and (−3,10). Besides, we find that Bitcoin, Ethereum and, Litecoin lived short bubbles lasting for a few days. However, Ripple and Tether markets present no bubbles and no explosive periods. Research limitations/implications This paper presents trained proof that FOMC announcements have a positive effect on volatility's predictive capacity. This work therefore promotes the study of the data quality of volatility in future research as well. Practical implications The justified effect of the FOMC announcements on cryptocurrency as a speculative asset has practical implications for investors in building their trading strategies in anticipation of the next FOMC announcement. Therefore, this study implies that the FOMC announcements contain very relevant information for investors in the cryptocurrency market. This research may not only encourage a better understanding of the evolution of the expectations of policymakers, but also facilitate a better understanding of how these expectations are developed. Originality/value The COVID-19 pandemic has disturbed the stability of financial markets, inciting the Fed to take some monetary regulations. To the best of our knowledge, this study is the first one that analyses the response of five major cryptocurrencies to FOMC announcements during COVID 19 pandemic and associates these dates with bubble occurrences.

scholarly journals A Digital Forensic Readiness Architecture for Online Examinations

2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Ivans Kigwana ◽  
H. S Venter
Keyword(s):  
Online Courses ◽  
Relevant Information ◽  
Content Management ◽  
International Standards ◽  
Future Research ◽  
International Electrotechnical Commission ◽  
Course Content ◽  
Digital Forensic ◽  
Online Examination ◽  
Proactive Measures

Some institutions provide online courses to students to ease the courses’ workload. Online courses can also be convenient because the online course content management software conducts marking of tests and examinations. However, a few students could be willing to exploit such a system’s weaknesses in a bid to cheat in online examinations because invigilators are absent. Proactive measures are needed and measures have to be implemented in order to thwart unacceptable behaviour in situations where there is little control of students’ conduct. Digital Forensic Readiness (DFR) employs a proactive approach for an organisation to be forensically prepared for situations where there is little control over people. This can be achieved by gathering, storing and handling incident response data, with the aim of reducing the time and cost that would otherwise be spent in a post-event response process. The problem this paper addresses is that, at the time of writing this paper, there existed no known DFR architecture that can be used to collect relevant information for DFR purposes, specifically in the course of an online examination, as described in the standard published by the International Standards Organisation (ISO) and the International Electrotechnical Commission (IEC) (ISO/IEC 27043:2015) for incident investigation principles and processes. Due to the lack of DFR architecture, the authors propose an Online Examination Digital Forensic Readiness Architecture (OEDFRA) that can be used to achieve DFR when online examinations are conducted. This architecture employs already existing DFR techniques, discussed in the study, to help educational institutions achieve DFR in online examinations. This architecture, (OEDFRA), when implemented, will be tested in future research in order to confirm its contribution to the field of DFR.

scholarly journals Carpooling in Connected and Autonomous Vehicles: Current Solutions and Future Directions

2022 ◽  
Author(s):  
Farkhanda Zafar ◽  
Hasan Ali Khattak ◽  
Moayad Aloqaily ◽  
Rasheed Hussain
Keyword(s):  
Business Model ◽  
Autonomous Vehicles ◽  
Research Work ◽  
Relevant Information ◽  
Security And Privacy ◽  
Future Research ◽  
Research Directions ◽  
Comprehensive Survey ◽  
One Stop ◽  
Future Research Directions

Owing to the advancements in communication and computation technologies, the dream of commercialized connected and autonomous cars is becoming a reality. However, among other challenges such as environmental pollution, cost, maintenance, security, and privacy, the ownership of vehicles (especially for Autonomous Vehicles (AV)) is the major obstacle in the realization of this technology at the commercial level. Furthermore, the business model of pay-as-you-go type services further attracts the consumer because there is no need for upfront investment. In this vein, the idea of car-sharing ( aka carpooling) is getting ground due to, at least in part, its simplicity, cost-effectiveness, and affordable choice of transportation. Carpooling systems are still in their infancy and face challenges such as scheduling, matching passengers interests, business model, security, privacy, and communication. To date, a plethora of research work has already been done covering different aspects of carpooling services (ranging from applications to communication and technologies); however, there is still a lack of a holistic, comprehensive survey that can be a one-stop-shop for the researchers in this area to, i) find all the relevant information, and ii) identify the future research directions. To fill these research challenges, this paper provides a comprehensive survey on carpooling in autonomous and connected vehicles and covers architecture, components, and solutions, including scheduling, matching, mobility, pricing models of carpooling. We also discuss the current challenges in carpooling and identify future research directions. This survey is aimed to spur further discussion among the research community for the effective realization of carpooling.

scholarly journals How does gaze to faces support face-to-face interaction? A review and perspective

2019 ◽  
Author(s):  
Roy S Hessels
Keyword(s):  
Visual Information ◽  
Relevant Information ◽  
Observational Research ◽  
Future Research ◽  
Dynamic Systems Theory ◽  
Face To Face ◽  
Vision Science ◽  
Literature Overview ◽  
Social Gaze ◽  
Human Social Behaviour

Gaze – where one looks, how long, and when – plays an essential part in human social behaviour. While many aspects of social gaze have been reviewed, there is no comprehensive review or theoretical framework that describes how gaze to faces supports face-to-face interaction. In this review, I address the following questions: (1) When does gaze need to be allocated to a particular region of a face in order to provide the relevant information for successful interaction; (2) How do humans look at other people, and faces in particular, regardless of whether gaze needs to be directed at a particular region to acquire the relevant visual information; (3) How does gaze support the regulation of interaction? The work reviewed spans psychophysical research, observational research and eye-tracking research in both lab-based and interactive contexts. Based on the literature overview, I sketch a framework for future research based on dynamic systems theory. The framework holds that gaze should be investigated in relation to sub-states of the interaction, encompassing sub-states of the interactors, the content of the interaction as well as the interactive context. The relevant sub-states for understanding gaze in interaction vary over different timescales from microgenesis to ontogenesis and phylogenesis. The framework has important implications for vision science, psychopathology, developmental science and social robotics.

Soil sodicity in Victoria

Soil Research ◽  
1993 ◽  
Vol 31 (6) ◽  
pp. 869 ◽  
Author(s):  
GW Ford ◽  
JJ Martin ◽  
P Rengasamy ◽  
SC Boucher ◽  
A Ellington
Keyword(s):  
Land Degradation ◽  
Management Practices ◽  
Agricultural Land ◽  
Current Knowledge ◽  
Relevant Information ◽  
Irrigated Agriculture ◽  
Future Research ◽  
Sodic Soils ◽  
Diverse Range ◽  
Key Issues

This paper gives a broad overview of the distribution and agricultural importance of sodic soils in Victoria. Sodic soils are estimated to occupy at least 13.4 Mha, representing at least 73% of Victoria's agricultural land. Most of this land is used for dryland farming; about 85% of the cropped land and 66% of the land sown to dryland pastures occurs on sodic soils. The largest sodicity class is 'alkaline sodic', dominated by a diverse range of soils (red duplex, yellow duplex, calcareous earths and self-mulching cracking clays). Alkaline sodic soils comprise half of the total agricultural land area, or about 24% of the area of land currently used for dryland cropping and 21% of the land under sown pasture. Land degradation problems are recognized as affecting most agricultural land in Victoria, and to be substantially limiting its productivity. The nature, extent and severity of the various forms of land degradation are a consequence of both intrinsic soil properties and of management practices. There is an urgent need to improve current farming practices to prevent further deterioration of the soil resource. Existing knowledge of the behaviour of sodic soils under both dryland and irrigated agriculture is reviewed. It is concluded that substantial gains in productivity are possible, but will require effective collaboration between soil scientists, agronomists, and land managers. Collation and integration of current knowledge on the properties and management of sodic soils in Victoria, and the acquisition of additional relevant information by targeted long-term research is required. Key issues for future research are identified.

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