The question of seed transmissibility of Plum pox virus

For many years, Plum pox virus (PPV) was considered to be transmissible by seed, increasing the fear of long-distance spread of the disease. In the late 1970s, it was claimed on the basis of biological transmission of the virus to herbaceous indicator plants and the development of serological diagnosis based on polyclonal antibodies, that PPV was seed-transmitted, with a different infection rate according to the plant species and part of the seed which was tested. In the 1990s, PPV was characterized into four different types, and specific monoclonal antibodies were produced for them. These new and more sensitive diagnostic techniques, together with RT-PCR with different sets of specific primers, were used to approach once again the problem of PPV transmission through seeds. The virus was detected in seed coats and cotyledons, but embryonic tissue and seedlings obtained from germinated seeds never showed symptoms, and gave negative results for PPV with both ELISA and PCR assays. No PPV isolate is currently recognized to be seed transmitted, so vertical transmission of PPV from infected mother plants to their progeny does not occur. Hypothetically, the only possibility of seed transmission would arise from a mutation in the helper component of the virus, associated with high susceptibility of the infected Prunus cultivar.     

Control of Plum pox virus through the use of genetically modified plants

Genetic resistance to Plum pox virus (PPV) is the most viable alternative for long-term control of sharka disease. In addition to the classical approaches to producing resistant germplasm and cultivars, genetic transformation offers a promising genetic approach to resistance. We show, using the example of C5 plum, that genetically engineered resistance can provide durable, stable and high levels of PPV resistance. A review of the results of work with C5 including molecular analyses of resistance and long-term field testing is presented.     

Detection of Plum pox virus: biological methods

This paper describes biological testing techniques for Plum pox virus (PPV), focussing in particular on woody indicators such as Prunus persica (L.) Batsch GF305 and P. tomentosa (Thunb.) Wall.     

李痘病毒及其风险分析

李痘病毒是危害核果类果树的重要病原物,具有传播迅速的特点,已被多个国家列为检疫性有害生物。本文对李痘病毒生物学特性等方面进行综述,通过分析该病毒的传播和定殖规律,并根据我国的具体生态情况,对其传入的可能性进行风险分析,结果认定其传入的可能性较大,需要制定严格的检疫措施,严防传入中国。