Genome-wide analyses have revealed that R (+)-Igmesine hydrochloride are very diverse and abundant in plant genomes ( Kohler et al., 2008, Meyers et al., 2003 and Zhou et al., 2004). Recently, the whole genome sequencing and assembly of the pepper C. annuum ‘CM334’ has been reported; 684R gene coding sequences were predicted in the pepper genome ( Kim et al., 2014). Pvr9 was previously cloned from a genomic DNA of the pepper C. annuum ‘Floral Gem’ based on sequence homology ( Tran et al., 2014). This R gene isolation strategy could detect R genes whose functions are not expressed in the original host but can be expressed in other plants. This is the case with Pvr9, which was isolated from a PepMoV-susceptible pepper but which conferred resistance to PepMoV in N. benthamiana. Pvr9 did not respond to PepMoV in pepper probably because an unknown factor that mediates the recognition of PepMoV NIb by Pvr9 protein is lacking in pepper. The failure to detect a direct interaction between the R gene and the elicitor suggested that a third factor is present in N. benthamiana but does not in peppers. Since neither homolog 1 from Floral Gem nor homolog 2 from CM334 is capable of inducing hypersensitivity, it is also worth noting that the homolog 1 is probably an allelic variant of Pvr9 in the pepper Floral Gem population. How the Pvr9 homologs present or evolve in the pepper Floral Gem as well as in the other cultivars remained to be clarified. As complete genome sequencing often identifies numerous allelic variants (sometimes hundreds) for a given gene, further study will determine significance of the genotype and corresponding phenotype using a sufficiently large population.
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