Current 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.
Corsi, B., Riccioni, L., Linthorst, H., Forni, C. (2014). A sustainable approach for Actinidia pest management. In 11th International Phytotechnologies Conference (pp.385). Thessaloniki : Grafima Pubblication.
A sustainable approach for Actinidia pest management
FORNI, CINZIA
2014-09-01
Abstract
Current 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.Questo articolo è pubblicato sotto una Licenza Licenza Creative Commons
