scholarly journals The role of signal production and transduction in induced resistance of harvested fruits and vegetables

2021 ◽  
Vol 5 ◽  
Author(s):  
Bin Wang ◽  
Yang Bi

Abstract Postharvest diseases are the primary reason causing postharvest loss of fruits and vegetables. Although fungicides show an effective way to control postharvest diseases, the use of fungicides is gradually being restricted due to safety, environmental pollution, and resistance development in the pathogen. Induced resistance is a new strategy to control postharvest diseases by eliciting immune activity in fruits and vegetables with exogenous physical, chemical, and biological elicitors. After being stimulated by elicitors, fruits and vegetables respond immediately against pathogens. This process is actually a continuous signal transduction, including the generation, transduction, and interaction of signal molecules. Each step of response can lead to corresponding physiological functions, and ultimately induce disease resistance by upregulating the expression of disease resistance genes and activating a variety of metabolic pathways. Signal molecules not only mediate defense response alone, but also interact with other signal transduction pathways to regulate the disease resistance response. Among various signal molecules, the second messenger (reactive oxygen species, nitric oxide, calcium ions) and plant hormones (salicylic acid, jasmonic acid, ethylene, and abscisic acid) play an important role in induced resistance. This article summarizes and reviews the research progress of induced resistance in recent years, and expounds the role of the above-mentioned signal molecules in induced resistance of harvested fruits and vegetables, and prospects for future research.

2020 ◽  
Vol 16 (4) ◽  
pp. 455-461
Author(s):  
Gabriela M. Baia ◽  
Otniel Freitas-Silva ◽  
Murillo F. Junior

Fruits and vegetables are foods that come into contact with various types of microorganisms from planting to their consumption. A lack or poor sanitation of these products after harvest can cause high losses due to deterioration and/ or pathogenic microorganisms. There are practically no post-harvest fungicides or bactericides with a broad spectrum of action that have no toxic residual effects and are safe. However, to minimize such problems, the use of sanitizers is an efficient device against these microorganisms. Chlorine is the most prevalent sanitizing agent because of its broad spectrum, low cost and well-established practices. However, the inevitable formation of disinfection by-products, such as trihalomethanes (THMs) and haloacetic acids (HAAs), is considered one of the main threats to food safety. Alternative sanitizers, such as chlorine dioxide (ClO2) and ozone, are becoming popular as a substitute for traditional post-harvest treatments. Thus, this review addresses the use of chlorine, chlorine dioxide and ozone emphasizing aspects, such as usage, safe application, spectrum of action and legislation. In order to ensure the quality and safety of final products, the adoption of well-prepared sanitation and sanitation programs for post-harvest fruits and vegetables is essential.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yuexin Zhang ◽  
Yapeng Fan ◽  
Cun Rui ◽  
Hong Zhang ◽  
Nan Xu ◽  
...  

As one of the cash crops, cotton is facing the threat of abiotic stress during its growth and development. It has been reported that melatonin is involved in plant defense against salt stress, but whether melatonin can improve cotton salt tolerance and its molecular mechanism remain unclear. We investigated the role of melatonin in cotton salt tolerance by silencing melatonin synthesis gene and exogenous melatonin application in upland cotton. In this study, applicating of melatonin can improve salt tolerance of cotton seedlings. The content of endogenous melatonin was different in cotton varieties with different salt tolerance. The inhibition of melatonin biosynthesis related genes and endogenous melatonin content in cotton resulted in the decrease of antioxidant enzyme activity, Ca2+ content and salt tolerance of cotton. To explore the protective mechanism of exogenous melatonin against salt stress by RNA-seq analysis. Melatonin played an important role in the resistance of cotton to salt stress, improved the salt tolerance of cotton by regulating antioxidant enzymes, transcription factors, plant hormones, signal molecules and Ca2+ signal transduction. This study proposed a regulatory network for melatonin to regulate cotton’s response to salt stress, which provided a theoretical basis for improving cotton’s salt tolerance.


1994 ◽  
Author(s):  
Edo Chalutz ◽  
Charles Wilson ◽  
Samir Droby ◽  
Victor Gaba ◽  
Clauzell Stevens ◽  
...  

Following preliminary observations by one of the collaborating scientists on this project and the completion of a 1-year, BARD-supported feasibility study (IS-1908-90F), this 3-year BARD project has been executed. The main objectives of the research were to elucidate biochemical and pathological aspects of UV-induced resistance in fruits and vegetables, to characterize physical and biological variables of induced resistance and delay of ripening, and to explore the application of the treatment as a control practice of postharvest diseases and shelf-life extension of fruits and vegetables. Our findings, which are detailed in numerous joint publications, have shown that the effect of UV-C light on induction of resistance and delay of ripening is a general one and of wide oddurrence. Apart from surface sterilization of the commodity, the reduction of decay of different fungi has been associated with and induced resistance phenomenon which gradually builds up within 24 to 48 hours after the UV treatment and can be reversed by visible light. In citrus, induced resistance has been associated with increased activity of the enzymes phenylalanine ammonia-lyase and peroxidase, and with the levels of endglucanase and chitinase. In tomato, resistance was correlated with the production of high levels of tomatine. Our study of some molecular aspects of the induced resistance in grapefruit has revealed the induction of a cDNA which represents a gene encoding for an isoflavone reductase-like protein that, in legumes, has been associated with phytoalexin biosynthesis. This gene was cloned and sequenced. Delay of ripening was associated in tomato with inhibition of ethylene production, carotenoid synthesis, and chlorophyll degradation and with the presence of high levels of polyamines. In peach fruit epiphytic populations of a yeast increased following the UV treatment. Pilot-size treatment and packing lines were constructed in the US and Israel to test the application of the UV treatment on a semi-commercial scale. Although effective in reduction of decay and delay of ripening, a number of problems will have to be addressed before practical application of this methodology can be realized. The main issues are associated with the temporal and variable response to the treatment, and its relationship to the maturity and date of harvest of the commodity.


Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1705
Author(s):  
András Künstler ◽  
Gábor Gullner ◽  
Attila L. Ádám ◽  
Judit Kolozsváriné Kolozsváriné Nagy ◽  
Lóránt Király

Sulfur (S) is an essential plant macronutrient and the pivotal role of sulfur compounds in plant disease resistance has become obvious in recent decades. This review attempts to recapitulate results on the various functions of sulfur-containing defense compounds (SDCs) in plant defense responses to pathogens. These compounds include sulfur containing amino acids such as cysteine and methionine, the tripeptide glutathione, thionins and defensins, glucosinolates and phytoalexins and, last but not least, reactive sulfur species and hydrogen sulfide. SDCs play versatile roles both in pathogen perception and initiating signal transduction pathways that are interconnected with various defense processes regulated by plant hormones (salicylic acid, jasmonic acid and ethylene) and reactive oxygen species (ROS). Importantly, ROS-mediated reversible oxidation of cysteine residues on plant proteins have profound effects on protein functions like signal transduction of plant defense responses during pathogen infections. Indeed, the multifaceted plant defense responses initiated by SDCs should provide novel tools for plant breeding to endow crops with efficient defense responses to invading pathogens.


10.28945/3641 ◽  
2017 ◽  
Vol 12 ◽  
pp. 001-016 ◽  
Author(s):  
Jan Gube ◽  
Seyum Getenet ◽  
Adnan Satariyan ◽  
Yaar Muhammad

Aim/Purpose: This paper considers the role of supervisors’ discipline expertise in doctoral learning from a student perspective. Background: Doctoral students need to develop expertise in a particular field of study. In this context, developing expertise requires doctoral students to master disciplinary knowledge, conventions and scholarship under the guidance of supervisors. Methodology : The study draws on a mixed-method approach, using an online survey and semi-structured interviews conducted with doctoral students. Contribution: The paper brings to the fore the role of supervisors’ discipline expertise on doctoral students’ research progress. Findings: The survey data suggest that doctoral students nominate their supervisors on the basis of their discipline expertise. They also view supervisors’ expertise as key to the development of ‘insider’ knowledge of their doctoral research. Recommendations for Practitioners: Supervisors play a pivotal role in helping doctoral students overcome intellectual barriers by imparting their discipline knowledge as well as balancing satisfactory doctoral completion rate and high quality student experience. Impact on Society : Doctoral supervision equips doctoral students with the right arsenal to be able to competently operate within their field and prepares them for their future research or professional career that demands a high level of discipline expertise. Future Research: The scope of the findings leaves open a discussion about the experiences of doctoral students matched with non-discipline expert supervisory teams; for example, the extent of the mismatch and its ramifications.


2015 ◽  
Vol 55 (12) ◽  
pp. 1376 ◽  
Author(s):  
J. G. Muir ◽  
C. K. Yao ◽  
P. G. Gibson

Advancement in technologies to identify and quantify bacterial species in the gastrointestinal tract has escalated interest in its microbiome worldwide. There is enormous interest in understanding the roles that bacterial species play in gastrointestinal health and overall wellbeing. What constitutes a ‘healthy gut microbiome’ includes: favourable fermentation-dependent characteristics such as butyrate supply to all regions, minimisation of putrefaction of proteins, and adequate laxation. The relative abundance of specific bacterial species with certain functional characteristics is also important and include: traditional prebiotic bacteria – Bifidobacteria; strongly butyrate-producing – Clostridium coccoides and Faecalibacterium prausnitzi as well as a mucus-associated bacterium Akkermansia muciniphila. Manipulation of diet and dietary factors may be essential to favourably influence these fermentation-dependent parameters and select for growth of beneficial bacterial species. In this regard, this laboratory has identified indigestible oligosaccharides with prebiotic effects and now has an extensive database that quantifies indigestible oligosaccharides in a wide variety of foods including whole grains, cereals, legumes, seeds, nuts, fruits and vegetables. Future research in this area should consider the role of dietary components that best establish and maintain a ‘healthy gut microbiome’.


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