Artichoke Italian virus (AILV) is a nepovirus infecting globe artichoke and other plants in the family Compositae. Recent surveys in Apulia (Southern Italy) have shown that AILV infections are very frequent and detrimental to globe artichoke verieties of the reflowering type highlighting the importance of establishing new fields with virus-free propagation material. A sanitation protocol based on meristem tip culture (MTC) proved ineffective for AILV elimination. By contrast, MTC combined with either in vitro or in vivo thermopterapy eradicated the virus, so that virusfree plants were obtained. Recent insights propose that RNA silencing could be involved in the degradation of viral RNAs before entering meristems, a mechanism that is enhanced by thermoterapy so that the combined action should produce virus-free plants. AILV is seed-transmitted thus, it must be able to overcome the meristem exclusion mechanism. Most plant viruses code for genes that counteract host-mediated RNA silencing but no silencing suppressors have been identified in nepoviruses. After an initial phase of symptom appearance, plants infected by nepoviruses usually undergo a phase of recovery in which symptoms disappear. The recovery phenotype was attributed to the inability of nepoviruses to contrast silencing but it is still a matter of discussion whether the recovery phenotype could be associated with a strong reduction of virus titre in recovered tissues or not. As a preliminary approach to understand why AILV escaped sanitation by MTC, we have addressed some of these points in AILV infections in tobacco.
ARTICHOKE ITALIAN LATENT VIRUS AND RNA SILENCING: IMPLICATIONS IN SANITATION SCHEMES OF NEPOVIRUS INFECTED PLANTS
Prigigallo MI;
2009
Abstract
Artichoke Italian virus (AILV) is a nepovirus infecting globe artichoke and other plants in the family Compositae. Recent surveys in Apulia (Southern Italy) have shown that AILV infections are very frequent and detrimental to globe artichoke verieties of the reflowering type highlighting the importance of establishing new fields with virus-free propagation material. A sanitation protocol based on meristem tip culture (MTC) proved ineffective for AILV elimination. By contrast, MTC combined with either in vitro or in vivo thermopterapy eradicated the virus, so that virusfree plants were obtained. Recent insights propose that RNA silencing could be involved in the degradation of viral RNAs before entering meristems, a mechanism that is enhanced by thermoterapy so that the combined action should produce virus-free plants. AILV is seed-transmitted thus, it must be able to overcome the meristem exclusion mechanism. Most plant viruses code for genes that counteract host-mediated RNA silencing but no silencing suppressors have been identified in nepoviruses. After an initial phase of symptom appearance, plants infected by nepoviruses usually undergo a phase of recovery in which symptoms disappear. The recovery phenotype was attributed to the inability of nepoviruses to contrast silencing but it is still a matter of discussion whether the recovery phenotype could be associated with a strong reduction of virus titre in recovered tissues or not. As a preliminary approach to understand why AILV escaped sanitation by MTC, we have addressed some of these points in AILV infections in tobacco.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
