Molecular characterization and host reaction to tomato mottle mosaic virus isolated from sweet pepper seeds in Japan

AbstractMany countries have identified tomato mottle mosaic virus (ToMMV) as a serious threat to tomato production. Here, we constructed and characterized infectious clones of ToMMV isolated from Japanese sweet pepper seeds. The genome of the Japanese isolate is 6399 nucleotides in length and exhibits the  highest identity with previously characterized isolates. For example, it is 99.7% identical to that of the Mauritius isolate, which occurs worldwide. Phylogenetic analysis based on complete genome sequences revealed that the Japanese isolates clustered in the same clade as those from other countr ies. When homozygous tomato cultivars with tobamovirus resistance genes were inoculated with an infectious cDNA clone of ToMMV, the virus systemically infected tomato plants with symptoms typical ofTm-1-carrying tomato cultivars. In contrast, tomato cultivars carryingTm-2 orTm-22 showed symptoms only on the inoculated leaves. Furthermore, when commercial cultivars ofTm-22 heterozygous tomato were inoculated with ToMMV, systemic infections were observed in all cultivars, with infection frequencies ranging from 25 to 100%. Inoculation of heterozygous sweet pepper cultivars with tobamovirus resistance genes (L1,L3, andL4) with ToMMV resulted in an infection frequency of about 70%, but most of the infectedL1,L3, andL4 cultivars were symptomless, and 10-20% showed symptoms of necrosis and yellowing. Tomato mosaic virus strain L11A, an attenuated virus, did not provide cross-protection...
Source: Archives of Virology - Category: Virology Source Type: research