Annually significant tomato yield losses are caused by climate changes and pests and diseases attacks. Root-knot nematodes (Meloidogyne spp.) are the most damaging pests on the base of their wide distribution in tropic and sub-tropic climates and their wide host range. They modify host root tissue using effector proteins to create feeding sites as their source of nutrition. To develop alternative control strategies to nematode infections, we have considered aqueous ozone treatments (AOT) as a possible tool. Although gaseous ozone is phytotoxic, previous studies demonstrated that ozone in aqueous phase is effective to contain pests. The purposes of this study were to confirm the impact of AOT on tomato-M. incognita interaction and to analyse its role in plant defence response. Ozonated water was produced in situ by an ozone generator at 10 ppm and directly applied to tomato roots. Treatments were performed daily (10 ml/pot) for 4 days as soil drench on 14 days old tomato plants maintained in a growth cabinet (25 ± 2 °C). Nematode infection control by ozone treatments was set up by infecting untreated and treated plants with J2s of M. incognita. A number of plants were used 2, 4 and 7 days after nematode infection for biochemical and molecular analysis. Other plants were transferred in a glasshouse at 25 ± 2 °C and after 60 days they were uprooted and dry shoot and root fresh weights recorded. Root gall index, eggs and J2s/g root, total nematode population density and reproduction rate were evaluated. AOT significantly decreased severity of root gall index and soil nematode population in comparison to untreated plants. Tomato sensitivity to AOT was verified as reactive oxygen species production (ROS) in both treated and untreated root galls and compared with uninfected treated and untreated roots. A higher significant ROS production was observed in ozone treated uninfected roots in comparison to treated and untreated infected roots. As antioxidant mechanisms play an important role in the response of plant to the combination of abiotic and biotic stresses, the effect of AOT on the expression of different genes involved in ROS scavenging, such as CAT, SOD and APX, was also evaluated. AOT by altering gene expression, ROS production and inducing a non specific defense response can be considered a useful tool to contain nematode infection. Aknowledgement: This work was supported with funds provided by the National Research Council for the project "Innovazione e Sviluppo del Mezzogiorno - Conoscenze Integrate per Sostenibilità ed Innovazione del Made in Italy Agroalimentare".
Influence of aqueous ozone treatments on tomato-Meloidogyne incognita interaction
Melillo MT;Veronico P;Laquale S;Sasanelli N
2015
Abstract
Annually significant tomato yield losses are caused by climate changes and pests and diseases attacks. Root-knot nematodes (Meloidogyne spp.) are the most damaging pests on the base of their wide distribution in tropic and sub-tropic climates and their wide host range. They modify host root tissue using effector proteins to create feeding sites as their source of nutrition. To develop alternative control strategies to nematode infections, we have considered aqueous ozone treatments (AOT) as a possible tool. Although gaseous ozone is phytotoxic, previous studies demonstrated that ozone in aqueous phase is effective to contain pests. The purposes of this study were to confirm the impact of AOT on tomato-M. incognita interaction and to analyse its role in plant defence response. Ozonated water was produced in situ by an ozone generator at 10 ppm and directly applied to tomato roots. Treatments were performed daily (10 ml/pot) for 4 days as soil drench on 14 days old tomato plants maintained in a growth cabinet (25 ± 2 °C). Nematode infection control by ozone treatments was set up by infecting untreated and treated plants with J2s of M. incognita. A number of plants were used 2, 4 and 7 days after nematode infection for biochemical and molecular analysis. Other plants were transferred in a glasshouse at 25 ± 2 °C and after 60 days they were uprooted and dry shoot and root fresh weights recorded. Root gall index, eggs and J2s/g root, total nematode population density and reproduction rate were evaluated. AOT significantly decreased severity of root gall index and soil nematode population in comparison to untreated plants. Tomato sensitivity to AOT was verified as reactive oxygen species production (ROS) in both treated and untreated root galls and compared with uninfected treated and untreated roots. A higher significant ROS production was observed in ozone treated uninfected roots in comparison to treated and untreated infected roots. As antioxidant mechanisms play an important role in the response of plant to the combination of abiotic and biotic stresses, the effect of AOT on the expression of different genes involved in ROS scavenging, such as CAT, SOD and APX, was also evaluated. AOT by altering gene expression, ROS production and inducing a non specific defense response can be considered a useful tool to contain nematode infection. Aknowledgement: This work was supported with funds provided by the National Research Council for the project "Innovazione e Sviluppo del Mezzogiorno - Conoscenze Integrate per Sostenibilità ed Innovazione del Made in Italy Agroalimentare".I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
