scholarly journals Role of Elicitors in Inducing Resistance in Plants against Pathogen Infection: A Review

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Meenakshi Thakur ◽  
Baldev Singh Sohal

Disease control is largely based on the use of fungicides, bactericides, and insecticides—chemical compounds toxic to plant invaders, causative agents, or vectors of plant diseases. However, the hazardous effect of these chemicals or their degradation products on the environment and human health strongly necessitates the search for new, harmless means of disease control. There must be some natural phenomenon of induced resistance to protect plants from disease. Elicitors are compounds, which activate chemical defense in plants. Various biosynthetic pathways are activated in treated plants depending on the compound used. Commonly tested chemical elicitors are salicylic acid, methyl salicylate, benzothiadiazole, benzoic acid, chitosan, and so forth which affect production of phenolic compounds and activation of various defense-related enzymes in plants. Their introduction into agricultural practice could minimize the scope of chemical control, thus contributing to the development of sustainable agriculture. This paper chiefly highlights the uses of elicitors aiming to draw sufficient attention of researchers to the frontier research needed in this context.

Revista CERES ◽  
2015 ◽  
Vol 62 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Edson Ampélio Pozza ◽  
Adélia Aziz Alexandre Pozza ◽  
Deila Magna dos Santos Botelho

All essential nutrients can affect the incidence and severity of plant diseases. Although silicon (Si) is not considered as an essential nutrient for plants, it stands out for its potential to decrease disease intensity in many crops. The mechanism of Si action in plant resistance is still unclear. Si deposition in plant cell walls raised the hypothesis of a possible physical barrier to pathogen penetration. However, the increased activity of phenolic compounds, polyphenol oxidases and peroxidases in plants treated with Si demonstrates the involvement of this element in the induction of plant defense responses. The studies examined in this review address the role of Si in disease control and the possible mechanisms involved in the mode of Si action in disease resistance in plants.


1971 ◽  
Vol 26 (03) ◽  
pp. 523-525
Author(s):  
K Gibiński ◽  
B Lipiński ◽  
M Trusz-Gluza

SummaryWhile the native fibrinogen is not digested by the leucocyte proteases both the early and late FDP are digestible without any denaturating reagent. Thus, this reaction may occur in vivo indicating an unknown role of granulocytes in paracoagulation.


1982 ◽  
Vol 48 (02) ◽  
pp. 201-203 ◽  
Author(s):  
N A Marsh ◽  
P J Gaffney

SummaryThe effect of strenuous exercise on the fibrinolytic and coagulation mechanisms was examined in six healthy male subjects. Five min bicycle exercise at a work-rate of 800 to 1200 kpm. min−1 produced an abrupt increase in plasma plasminogen activator levels which disappeared after 90 min. However, there was no change in early or late fibrin degradation products nor was there a change in fibrinopeptide A levels or βthromboglobulin levels after exercise although activated partial thromboplastin times were significantly shortened. It is concluded that strenuous exercise does not produce any real increase in fibrinogen-fibrin conversion nor any real increase in the breakdown of these proteins. The role of exercise-induced release of plasminogen activator remains unclear, but probably helps to maintain plasma levels in a discontinuous manner concurrently with the continuous low-level secretion from the vascular wall. The shortening of partial thromboplastin time may be due to the raised levels of plasminogen activator changing the activation state of other coagulation factors.


2020 ◽  
Author(s):  
S Weiß ◽  
A Korthaus ◽  
K-H Frosch ◽  
C Schlickewei ◽  
M Priemel

Author(s):  
Zeba Mueed ◽  
Pankaj Kumar Rai ◽  
Mohammad A. Kamal ◽  
Nitesh Kumar Poddar

Alzheimer’s disease (AD), characterized by abnormally phosphorylated tau, paired helical filaments (PHFs), neurofibrillary tangles (NFTs), deregulated mammalian target of rapamycin (mTOR), Aβ deposits, is a multifactorial disease with sleep disorders being one of the causative agents. Therefore, we have reviewed the literature and have tried to decode the existence of positive feedback, reciprocal and a bidirectional relationship allying between sleep disturbances and AD. Much light has been thrown on the role of tau pathology and amyloid pathology in sleep pathology and its association with AD pathology. We have also discussed the role of melatonin in regulating sleep disorders and AD. The neuroprotective action of melatonin via inhibiting tau hyperphosphorylation and Aβ deposition has also been pondered upon. Moreover, astrocytes involvement in aggravating AD has also been highlighted in this review. Several therapeutic approaches aimed at improving both sleep disorders and AD have been duly discussed such as administration of antidepressants and antihistamines, immunotherapy, metal chelators, melatonin supplementation, light therapy and physical activity. Despite consistent efforts, the complete etiology concerning sleep disorder and AD is still unclear. Therefore, further research is needed to unravel the mechanism involved and also to develop strategies that may help in obstructing AD in its preclinical stage.


2021 ◽  
Vol 11 (12) ◽  
pp. 5413
Author(s):  
Keiko Iwasa ◽  
Harumichi Seta ◽  
Yoshihide Matsuo ◽  
Koichi Nakahara

This paper reports on the chemical compounds in arabica coffee beans with a high Specialty Coffee Association (SCA) cupping score, especially those in specialty coffee beans. We investigated the relationship between the chemical compounds and cupping scores by considering 16 types of Coffea arabica (arabica coffee) beans from Guatemala (SCA cupping score of 76.5–89.0 points). Non-targeted gas chromatography-mass spectrometry-based chemometric profiling indicated that specialty beans with a high cupping score contained considerable amounts of methyl-esterified compounds (MECs), including 3-methylbutanoic acid methyl ester (3-MBM), and other fatty acid methyl esters. The effect of MECs on flavor quality was verified by spiking the coffee brew with 3-MBM, which was the top-ranked component, as obtained through a regression model associated with cupping scores. Notably, 3-MBM was responsible for the fresh-fruity aroma and cleanness of the coffee brew. Although cleanness is a significant factor for specialty beans, the identification of compounds that contribute to cleanness has not been reported in previous research. The chemometric profiling approach coupled with spiking test validation will improve the identification and characterization of 3-MBM commonly found in arabica specialty beans. Therefore, 3-MBM, either alone or together with MECs, can be used as a marker in coffee production.


2021 ◽  
Vol 83 (8) ◽  
Author(s):  
F. Al Basir ◽  
Y. N. Kyrychko ◽  
K. B. Blyuss ◽  
S. Ray

AbstractMany plant diseases are caused by plant viruses that are often transmitted to plants by vectors. For instance, the cassava mosaic disease, which is spread by whiteflies, has a significant negative effect on plant growth and development. Since only mature whiteflies can contribute to the spread of the cassava mosaic virus, and the maturation time is non-negligible compared to whitefly lifetime, it is important to consider the effects this maturation time can have on the dynamics. In this paper, we propose a mathematical model for dynamics of cassava mosaic disease that includes immature and mature vectors and explicitly includes a time delay representing vector maturation time. A special feature of our plant epidemic model is that vector recruitment is negatively related to the delayed ratio between vector density and plant density. We identify conditions of biological feasibility and stability of different steady states in terms of system parameters and the time delay. Numerical stability analyses and simulations are performed to explore the role of various parameters, and to illustrate the behaviour of the model in different dynamical regimes. We show that the maturation delay may stabilise epidemiological dynamics that would otherwise be cyclic.


2021 ◽  
pp. 009524432110061
Author(s):  
Bo Yang ◽  
Balakrishnan Nagarajan ◽  
Pierre Mertiny

Polymers may absorb fluids from their surroundings via the natural phenomenon of swelling. Dimensional changes due to swelling can affect the function of polymer components, such as in the case of seals, microfluidic components and electromechanical sensors. An understanding of the swelling behavior of polymers and means for controlling it can improve the design of polymer components, for example, for the previously mentioned applications. Carbon-based fillers have risen in popularity to be used for the property enhancement of resulting polymer composites. The present investigation focuses on the effects of three carbon-based nano-fillers (graphene nano-platelets, carbon black, and graphene nano-scrolls) on the dimensional changes of polydimethylsiloxane composites due to swelling when immersed in certain organic solvents. For this study, a facile and expedient methodology comprised of optical measurements in conjunction with digital image analysis was developed as the primary experimental technique to quantify swelling dimensional changes of the prepared composites. Other experimental techniques assessed polymer cross-linking densities and elastic mechanical properties of the various materials. The study revealed that the addition of certain carbon-based nano-fillers increased the overall swelling of the composites. The extent of swelling further depended on the organic solvent in which the composites were immersed in. Experimental findings are contrasted with published models for swelling prediction, and the role of filler morphology on swelling behavior is discussed.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Guojun Wu ◽  
Naisi Zhao ◽  
Chenhong Zhang ◽  
Yan Y. Lam ◽  
Liping Zhao

AbstractTo demonstrate the causative role of gut microbiome in human health and diseases, we first need to identify, via next-generation sequencing, potentially important functional members associated with specific health outcomes and disease phenotypes. However, due to the strain-level genetic complexity of the gut microbiota, microbiome datasets are highly dimensional and highly sparse in nature, making it challenging to identify putative causative agents of a particular disease phenotype. Members of an ecosystem seldomly live independently from each other. Instead, they develop local interactions and form inter-member organizations to influence the ecosystem’s higher-level patterns and functions. In the ecological study of macro-organisms, members are defined as belonging to the same “guild” if they exploit the same class of resources in a similar way or work together as a coherent functional group. Translating the concept of “guild” to the study of gut microbiota, we redefine guild as a group of bacteria that show consistent co-abundant behavior and likely to work together to contribute to the same ecological function. In this opinion article, we discuss how to use guilds as the aggregation unit to reduce dimensionality and sparsity in microbiome-wide association studies for identifying candidate gut bacteria that may causatively contribute to human health and diseases.


2021 ◽  
Vol 7 (3) ◽  
pp. 202
Author(s):  
Johannes Delgado-Ospina ◽  
Junior Bernardo Molina-Hernández ◽  
Clemencia Chaves-López ◽  
Gianfranco Romanazzi ◽  
Antonello Paparella

Background: The role of fungi in cocoa crops is mainly associated with plant diseases and contamination of harvest with unwanted metabolites such as mycotoxins that can reach the final consumer. However, in recent years there has been interest in discovering other existing interactions in the environment that may be beneficial, such as antagonism, commensalism, and the production of specific enzymes, among others. Scope and approach: This review summarizes the different fungi species involved in cocoa production and the cocoa supply chain. In particular, it examines the presence of fungal species during cultivation, harvest, fermentation, drying, and storage, emphasizing the factors that possibly influence their prevalence in the different stages of production and the health risks associated with the production of mycotoxins in the light of recent literature. Key findings and conclusion: Fungi associated with the cocoa production chain have many different roles. They have evolved in a varied range of ecosystems in close association with plants and various habitats, affecting nearly all the cocoa chain steps. Reports of the isolation of 60 genera of fungi were found, of which only 19 were involved in several stages. Although endophytic fungi can help control some diseases caused by pathogenic fungi, climate change, with increased rain and temperatures, together with intensified exchanges, can favour most of these fungal infections, and the presence of highly aggressive new fungal genotypes increasing the concern of mycotoxin production. For this reason, mitigation strategies need to be determined to prevent the spread of disease-causing fungi and preserve beneficial ones.


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