In agriculture, the economic losses due to plant diseases caused by infectious agents are constantly growing. In Italy, bacteria have recently caused outbreaks in crops of great economic impact: Pseudomonas syringae pv. actinidiae (Psa) for the bacterial canker of kiwifruit; Xylella fastidiosa, for the “Olive quick decline syndrome” and Erwinia amylovora (Ea) for the fire blight of pome-fruit trees. The control of these diseases relies almost exclusively on the use of copper compound sprays. It is therefore urgent to develop bactericidal products active in the plant or able to interfere with the growth of the pathogen already present as an endophyte in the host plant that can remain asymptomatic for years due to a long latent period. The idea to exploit the antimicrobial activity of essential oils (EO) to counteract the pathogens’ growth is increasingly taken into account. The antimicrobial effects of EO from Monarda spp. against Psa and Ea recently shown in vitro, allow to hypothesize their protection effect in planta against Psa. The EO and the hydrolate extracted by steam distillation from M. didyma flowering plants were tested to prevent the disease symptoms in Actinidia deliciosa cv. Tomouri plants induced by a Psa virulent strain. Four groups of plants were subjected to different pretreatments with: 1) sterile distilled water (positive control); hydrolate (14.7%); EO (0.3%) and streptomycin (negative control). 24 h later, they were inoculated with the Psa IPV-BO 8101 strain. Leaf spots characteristic of Psa were evidenced in the control plants starting from 8 days after the inoculation. The plants were monitored over the following two months to highlight the symptoms induced by Psa and any damages caused by each treatment. At the end of the trial, all leaves were collected from each plant to determine the number of spots/leaf/plant for statistical analysis. The protective effect of the EO/hydrolate, was correlated with their chemical compositions determined by GC/MS analysis. These results are encouraging for further research in this direction to safeguard health of plants and humans.
Bacterial canker of kiwifruit: antimicrobial activity of Monarda spp. essential oils against Pseudomonas syringae pv. actinidiae
Minardi Paola;Bellardi Maria Grazia
2016
Abstract
In agriculture, the economic losses due to plant diseases caused by infectious agents are constantly growing. In Italy, bacteria have recently caused outbreaks in crops of great economic impact: Pseudomonas syringae pv. actinidiae (Psa) for the bacterial canker of kiwifruit; Xylella fastidiosa, for the “Olive quick decline syndrome” and Erwinia amylovora (Ea) for the fire blight of pome-fruit trees. The control of these diseases relies almost exclusively on the use of copper compound sprays. It is therefore urgent to develop bactericidal products active in the plant or able to interfere with the growth of the pathogen already present as an endophyte in the host plant that can remain asymptomatic for years due to a long latent period. The idea to exploit the antimicrobial activity of essential oils (EO) to counteract the pathogens’ growth is increasingly taken into account. The antimicrobial effects of EO from Monarda spp. against Psa and Ea recently shown in vitro, allow to hypothesize their protection effect in planta against Psa. The EO and the hydrolate extracted by steam distillation from M. didyma flowering plants were tested to prevent the disease symptoms in Actinidia deliciosa cv. Tomouri plants induced by a Psa virulent strain. Four groups of plants were subjected to different pretreatments with: 1) sterile distilled water (positive control); hydrolate (14.7%); EO (0.3%) and streptomycin (negative control). 24 h later, they were inoculated with the Psa IPV-BO 8101 strain. Leaf spots characteristic of Psa were evidenced in the control plants starting from 8 days after the inoculation. The plants were monitored over the following two months to highlight the symptoms induced by Psa and any damages caused by each treatment. At the end of the trial, all leaves were collected from each plant to determine the number of spots/leaf/plant for statistical analysis. The protective effect of the EO/hydrolate, was correlated with their chemical compositions determined by GC/MS analysis. These results are encouraging for further research in this direction to safeguard health of plants and humans.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
