Data di Pubblicazione:
2011
Citazione:
Conventional and novel strategies for the phytoplasma diseases containment / P.A. Bianco, D. Bulgari, P. Casati, F. Quaglino. ((Intervento presentato al convegno Emerging phytoplasma diseases of stone fruits and other crops and their possible impact on EU Countries : COST Action FA0807,
Integrated Management of Phytoplasma Epidemics in Different Crop Systems tenutosi a Istanbul nel 2011.
Abstract:
Phytoplasmas are obligate bacterial plant pathogens that cause economically relevant yield losses in
annual and perennial crops worldwide and they are transmitted in nature by phloem feeders, mostly
leafhoppers, planthoppers and psyllids. Impossibility of cultivating phytoplasma impairs the development
of efficient methods to control these pathogens. Conventional strategies for phytoplasma containment
are based on pesticide application against insect vectors and the use of resistant plants (when available).
Owing to the great yield losses caused by phytoplasmas, their absence from propagation materials is
essential for sustainable plant production. This is particularly important for vegetatively propagated crops
in which infected planting materials transmit the pathogen to the new crop. Pathogen‐free plants have
been obtained using many different techniques, such as shoot tip culture, thermotherapy, leaf tissuederived
somatic embryogenesis, stem culture, treatment of plant tissues with antibiotics and cryotherapy
of shoot tips. Moreover, other strategies have been tested, namely: (i) production of transgenic plants
expressing antibodies against the major phytoplasma membrane protein (ii) production of transgenic
plants expressing antimicrobial peptides; and (iii) protecting the plants using elicitins, small proteins that
stimulate P protein plugs and callose release in phloem sieve elements (Laimer et al., 2009). Till today,
such treatments against phytoplasmas have been proved partially ineffective.
Current studies evidenced that a promising approach concerns the use of natural or induced
resistance. Different compounds tested as resistance inducers were able to suppress symptoms on
specific phytoplasma strain but they have limited applications (Romanazzi et al., 2009). Recently,
there has been an increasing interest in the use of biocontrol agents that could be employed in
different strategies: (i) study of microorganisms which are pathogenic to the insect (Schnepf et al.,
1998), (ii) symbiotic microorganisms able to reduce vector competence (Beard et al., 1998); (iii)
antagonisms mediated by the production of allelochemicals; (iv) induction of plant defense response.
For example, reduced symptom expression in phytoplasma‐infected plants treated with arbuscular
mycorrhizal fungi (Kaminska et al., 2010) and Epicoccum nigrum Link (Musetti et al., 2011) were
recently reported. Moreover, studies on bacteria as potential biocontrol agents or plant resistance
inducers have given promising results (Gamalero et al., 2010; Bulgari et al., 2011).
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Elenco autori:
P.A. Bianco, D. Bulgari, P. Casati, F. Quaglino
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