1,720,996 research outputs found
Is tall fescue (Festuca arundinacea Schreb.) a good tool to recover soils affected by salinity?
No full textEffect of chitosan seed treatment as elicitor of resistance to Fusarium graminearum in wheat.
No full textThe potential ability of chitosan seed treatment to induce resistance in plants of durum wheat (Triticum durum) against the seed borne fungal pathogen Fusarium graminearum, one of the main causal agents of root and foot rot in wheat, was evaluated. The chitosan seed treatment efficacy was evaluated by biochemical analyses, comparing: seed treated, seed treated and inoculated with the fungus, seed not treated and inoculated, seeds not treated and not inoculated. The enzymatic activities of some enzymes involved in defense mechanisms were analysed: guaiacol peroxidase (POD), ascorbate peroxidase (APX), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL), as well as the phenol content. Seed treatment induced changes in the enzymatic activities and increased phenol production. Greenhouse trials were performed with inoculated soil and the disease incidence on the plants was significantly reduced by chitosan seed treatment. Finally, field trials were conducted with inoculated seeds and then treated with chitosan. The chitosan seed treatment induced a decrease in disease severity and enhanced quantitative yield parameters, suggesting the possibility of the use of chitosan as a seed treatment in crop protection in order to improve the plant defense response
An overview of the plant response to pathogen attack: chitosan as a general elicitor of induced resistance in plants.
No full textPlant disease resistance is the ability of a plant to prevent or restrict pathogen growth and multiplication. All plants, whether they are resistant or susceptible, respond to pathogen attack by the induction of coordinate signalling system, which required the accumulation of different gene products. In plant immunity general elicitors, including chitin/chitosan oligomers are able to induce host defence response by binding to specific molecule
Effect of Neotyphodium, endophyte symbiont of Festuca arundinacea Schreb., on tolerance to NaCl .
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In vitro cultures of Actinidia deliciosa (A. Chev) C.F. Liang & A.R. Ferguson: a tool to study the SAR induction of chitosan treatment.
No full textKiwifruit (Actinidia deliciosa (A. Chev.) C.F.
Liang & A.R. Ferguson), a profitable crop with a steady
growth in export, should be certainly preserved from the
most common diseases. Kiwi plants were strengthened
with a natural compound, the chitosan, a well-known
elicitor of Systemic Acquired Resistance (SAR), to
study and evaluate the interaction between this compound
and in vitro cultures, in order to propose a possible
alternative to reduce the number of chemical pesticide
treatments in the prevention of disease outbreak. To
detect the effectiveness in eliciting SAR, the effects 15
and 50 mg/L of chitosan on kiwi micropropagated
plants were tested at the in vitro multiplication stage.
Different biochemical markers were measured, like phenols
and several enzymes involved in defence response,
i.e. guaiacol-peroxidase (G-POD), ascorbate peroxidase
(APX), phenylalanine ammonia lyase (PAL) and polyphenol
oxidase (PPO). The beneficial growth effect was
also evaluated measuring the dry biomass and the total
soluble protein content of treated plants. The systemic
disease protection elicited by chitosan has been detected
thanks to its ability to enhance the activity of enzymes
involved in detoxification processes (G-POD and APX)
and in increasing plant defence barriers (PAL and PPO).
In addition, chitosan treatment increased both dry biomass
and protein contents demonstrating a general enhancement
of plant fitness
Chitosan in Agriculture: A New Challenge for Managing Plant Disease
No full textIn recent years, environmental friendly measures have been developed for managing crop diseases as alternative to chemical pesticides, including the use of natural compounds such as chitosan. In this chapter, the common uses of this natural product in agriculture and the potential uses in plant disease control are reviewed. The last advanced researches as seed coating, plant resistance elicitation and soil amendment applications are also described. Chitosan is a deacetylated derivative of chitin, that is naturally present in the fungal cell wall and in crustacean shells from which it can be easily extracted. Chitosan have been reported to possess antifungal and antibacterial activity and it showed to be effective against seed-borne pathogens when applied as seed treatment. It can form physical barriers (film) around the seed surface and it can vehicular other antimicrobial compounds that could be added to the seed treatments. Chitosan behaves as a resistance elicitor inducing both local and systemic plant defense responses even when applied to the seeds. The chitosan used as soil amendment was shown to give many benefits to different plant species by reducing the pathogen attack and infection. Concluding, the chitosan is an active molecule that finds many possibilities for application in agriculture, including plant disease control
Enhancement of PR1 and PR5 gene expressions by chitosan treatment in kiwifruit plants inoculated with Pseudomonas syringae pv. Actinidiae.
No full textKiwifruit, with a production of more than 1.5 million tons/year in the world, must be protected against
attack by its most common pathogen. Following the European guidelines on the substitution of pesticides by
safer alternatives, the aim of this work was to verify if kiwifruit plants are able to better resist pathogen infections
through the use of chitosan, a biodegradable compound and a well-known elicitor of Systemic Acquired
Resistance (SAR). To evaluate the chitosan’s elicitation effect in plant during the treatment period, two genes
involved in the metabolic pathway of SAR were chosen, Pathogenesis Related Protein 1 and 5 (PRs). Primers for both genes were designed and validated and chitosan’s elicitation effect was tested in qRT-PCR. Elicitation of SAR was first evaluated in a model system with plants cultured in vitro and subsequently in 2 year old plants
belonging to two different species (Actinidia chinensis Planch. and A. deliciosa (A. Chev.) C.F. Liang & A.R.
Ferguson). To evaluate the effects of chitosan elicitation in the presence of the pathogen attack, the 2-year-old
plants were inoculated with the bacterium Pseudomonas syringae pv. actinidiae. Micropropagated
kiwifruit plants were a good model to test molecular markers for SAR onset. Moreover, PR1 and PR5 have
also shown to be suitable candidates for the detection of the plant immune system activation. In this study, chitosan elicited a systemic response in kiwi plants with intensity comparable to other well-known signalling
compounds (salicylic acid, methyl jasmonate or ethylene), as shown by the changes in PR1’s and PR5’s
transcription profiles. The data obtained by chitosan treatments in in vitro cultures were confirmed in plants
grown in greenhouse, in which, moreover, the combination of chitosan treatment and the bacterial inoculum had the greatest effect on PRs synthesis. This study also proved that chitosan, leading to an increased expression of both PRs, has a role in kiwifruit defense reactions
A sustainable approach for Actinidia pest management
No full textCurrent strategies to contain emerging diseases in growing kiwifruits involve the massive use of pesticides. Their high doses applied increase the risk of pollution with consequences to the soil fauna and human health. In order to reduce the negative impact on the environment, the European Economic Community adopted a new legislative framework on pesticides to foresee the replacement of chemical substances with natural ones. Following this European trend, the aim of this work is to improve the quality production of Actinidia by growing plants able to better resist pathogen infection through the use of chitosan, a natural and biodegradable, well-known elicitor of Systemic Acquired Resistance (SAR).
Two years old plants of yellow (A. chinensis Planch.) and green (A. deliciosa (A. Chev.) Liang & Ferguson) kiwifruits were inoculated with Pseudomonas syringae pv. actinidiae(PSA), an important and emerging threat of kiwi plants in Italy, 24 hours after soil chitosan treatment and maintained in a quarantine greenhouse. The SAR’s onset was determined 2 weeks after the bacterial inoculation with the detection of plant response to the infection by biochemical analyses. In particular, to evaluate the link between chitosan and SAR, the activities of enzymes involved in biotic stress response were determined, i.e. antioxidant enzymes guaiacol peroxidase (G-POD) and ascorbate peroxidase (APX), and those of phenolic compounds pathway (phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO)).
According to the results, both species treated with chitosan counteracted the pathogen attack in a similar way. In fact, after elicitor application the activities of antioxidant enzymes (G-POD and APX) and of enzymes involved in strenghtening plant defence barriers (PAL and PPO) were increased in both species. Moreover, the higher phenol amounts observed after the treatement further confirmed chitosan’s role in eliciting plant responses against the pathogen.
Further tests on chitosan’s potential as an elicitor of SAR in kiwifruit plants are in progress. A rapid method to evaluate its effect has been adopted. Following a screening of possible SAR molecular markers, two members of Pathogenesis Related Protein families (PR1 and PR5) were chosen and two primers pairs were designed for measuring PR gene expression. A quantitative method such as qRT-PCR will be used to quantify the elicitation induced by chitosan at the molecular level during different developmental stages of kiwi plants.
This study has shown the reliability of chitosan treatment in eliciting plant defence response and its potential in the protection against PSA. Thus chitosan might be considered a sustainable and eco-friendly alternative to the traditional and hazardous pesticides for kiwi pest management, in order to reduce the number of chemical treatments
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