Timing and extent of hypersensitive response are critical to restrict local and systemic spread of Pepper mild mottle virus in pepper containing the L 3 gene

Amino acid changes in Pepper mild mottle virus (PMMoV) coat protein (CP) that enhance, decrease, or nullify the resistance-inducing activity in Capsicum plants carrying the L ³ gene have been identified. In this study, molecular events underlying the L ³ -gene-mediated resistance were analyzed through the expression of hypersensitive response (HR)-related genes, HSR203J-Cc and HIN1-Cc, and defense-related genes, PR1-Cc and PR4b-Cc, upon infection with PMMoV CP mutants. The expression kinetics of the genes correlated with the degree of restriction of virus distribution in the inoculated leaves. The results suggest that the timing and extent of HR are critical factors to restrict virus spread both locally and systemically in L ³ -gene-mediated resistance.The nucleotide sequence data reported are available in the DDBJ/GenBank/EMBL databases under accession numbers AB162220 (HSR203J-Cc), AB162221 (HIN1-Cc), AB162222 (PR1-Cc), and AB162223 (PR4b-Cc)