Peach latent mosaic viroid

Peach latent mosaic viroid (binomial name Pelamoviroid latenspruni)(PLMVd) is a species of the genus Pelamoviroid, which belongs to the family Avsunviroidae. This family is characterized as having chloroplastic viroids with hammerhead ribozymes. In other words, these viruses are known to localize within the chloroplasts of plant cells and utilize hammerhead ribozymes to mediate self-cleavage and ligation of replication intermediates. Peach latent mosaic viroid was first described in the 1980s in Spain by a group of scientists.It is present in all peach- and nectarine-producing areas of the world including Europe, Asia, North America and South America and the frequency of naturally occurring infection is high. Before the development of symptoms the disease is latent in peach trees for approximately 5–7 years. The symptoms of the disease include necrosis of buds, delayed shoot development, necrotic branches, premature ageing of trees, flower streaking, ripening deformations, enlarged rounded stones, circular discolored areas on the fruit skin and in some cases mosaic, blotch, vein banding or calico appearance on infected leaves. An interesting biochemical property is that PLMVd has reduced solubility in highly saline conditions (e.g. 2 M LiCl), which is thought to relate to its branched structure. Some studies suggest the existence of a 2′,5′-phosphodiester bond in circular forms, possibly contributing to structural stability and influencing cleavage/ligation balance.

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