Lettuce mosaic virus 4347601 225494515 2008-07-14T00:10:43Z Blechnic 6713598 enough articles link to it --it's on the appropriate lists {{Taxobox | color=violet | name = Potyviridae | virus_group = IV | familia = Potyviridae | genus = ''[[Potyvirus]]'' }} ''Lettuce mosaic virus'' (LMV) is a typical potyvirus (genus ''Potyvirus'', family ''[[Potyviridae]]''), which causes one of the major [[virus]] [[disease]]s of [[lettuce]] crops world-wide. LMV is [[seed]]-borne to a low but significant rate (1-10% of the seeds produced by an infected mother plant [[germinate]] into infected [[seedling]]s). This provides the primary inoculum in lettuce crops. LMV, and thus the mosaic disease, is then spread locally from plant to plant by the feeding [[stylet]]s of [[aphid]]s. Like all [[plant virus]]es, LMV is totally harmless to the consumer but causes defects in heading, leaf [[distortion]]s and leaf colour anomalies, which altogether result in the infected lettuce plants to be unmarketable. Disease rates can reach 100% locally, and therefore cause complete loss of the [[harvest]]. LMV can also infect other crops such as [[spinach]] and [[pea]]s, as well as ornamentals (especially the [[Osteospermum|Cape Daisy]] ''Osteospermum spp'') and wild plants (especially the [[Lactuca|prickly lettuce]] ''Lactuca serriola'' and the [[oxtongue]] ''Helminthia echioides''). All these plants, and probably others, can serve as local sources from which LMV can spread to crops. == Prevention == Like other [[disease]]s caused by viruses in [[plant]]s, there is no mean to [[cure]] plants from LMV once they are [[infected]]. Prevention of LMV can however be relatively efficient based on: *control of the absence of LMV in seed lots before [[Trade|trading]]; typically, [[ELISA]] is used and a rejection rate of 1 out of 30,000 seeds is applied; *the use of the [[recessive]] [[disease resistance in fruit and vegetables|resistance]] [[gene]] ''mo1''; ''mo1'' has two commercial [[allele]]s (''mo1''¹, formerly known as ''g'', and ''mo1''², formerly known as ''mo''), both of which protect plants against LMV accumulation and, in some cases where LMV nevertheless accumulates, protect against [[symptom]] expression as well as prevents transmission through seed. In the late twentieth century, a novel type of LMV appeared in lettuce crops around the world. It was called LMV-Most ('''mo'''1-breaking, '''S'''eed-'''T'''ransmitted) to account for its ability to infect and to spread through seeds even in the presence of ''mo1''. Therefore, LMV-Most can only be prevented by controlling seeds, which consumes time, effort and money. ==External links== *[http://www.dpvweb.net/dpv/showdpv.php?dpvno=399 LMV in the Description of Plant Viruses edited by the Association of Applied Biologists] [[Category:Viruses]] [[Category:Plant pathogens and diseases]] [[Category:Lettuce diseases]] {{virus-plant-disease-stub}}