Comparison of two Near-Isogenic Lines of Bell Pepper (Capsicum annuum): One Endornavirus-Infected and the Other Endornavirus-Free

Abstract

Bell pepper (Capsicum annuum) is an economically important food crop cultivated worldwide. So far, all tested commercial cultivars have been shown to be infected with Bell pepper endornavirus (BPEV). Although BPEV does not cause apparent disease, the effect of this virus on bell pepper has not been investigated. A comparative study that included plant phenotype and some physiological characteristics was conducted with two near-isogenic lines (NIL) of the bell pepper cv. Marengo: one infected with BPEV and the other BPEV-free. The interaction of BPEV with a disease-causing virus of pepper, Pepper mild mottle virus (PMMoV), was also investigated. Differences in the overall phenotypic characteristics between the two bell pepper lines were not observed. Comparisons of the vegetative growth which included plant growth habit, plant height, stem thickness, fruit size, and percentage of dry matter did not yield statistically significant differences. The BPEV-free line showed significantly higher percentage of seed germination and root length, and the total fruit weight obtained from the BPEV-negative line was significantly higher than the fruit weight from the BPEV-infected line. A field isolate of PMMoV was characterized and used to conduct an interaction study between BPEV and PMMoV. Mechanical inoculations of PMMoV to the bell pepper NILs resulted in less severe symptoms in the BPEV-infected line than in the BPEV-free line. The BPEV-infected line also yielded lower virus titer and viral RNA accumulation. Although the virus titer and RNA accumulation data analyses did not result in statistically significant differences, the negative effect of BPEV on PMMoV was consistent in the various tests, suggesting that BPEV has an antagonistic effect on PMMoV. The overall results of this investigation suggest that infections of bell pepper by BPEV could have a negative effect on bell pepper production. However, more comparative studies involving biotic and abiotic agents should be conducted to determine other effects that BPEV may have on bell pepper.