A Pathotype of Pepper mild mottle virus Causing Necrotic Spot Symptoms in Paprika Fruit

Abstract

Black necrotic spots were observed from the fruits of paprika that were cultivating in a vinylhouse. The casual agents of the symptom were identified as several isolates of Pepper mild mottle virus (PMMoV) by responses of indicator plants, electron microscopy, and RT-PCR analysis. Symptoms of the viral disease were mild mottle in the young leaves, necrotic spots on the fruits and the fruit apex of paprika, but the symptoms were not shown on the mature leaves. All of the PMMoV isolates were determined as P 1.2.3 pathotypes from the biological responses on the chilli pepper lines used for discrimination of tobamovirus pathotypes. Pathogenicity of the PMMoV isolates was also confirmed using mechanical inoculation method to paprika seedlings. The coat protein (CP) genes of the PMMoV isolates were compared at the nucleotide and amino acid levels with the previously published PMMoV isolate. The isolates share 96 to 99% CP nucleotide identity among the isolates. The CP of P 1.2-pathotype PMMoV-P2 presented Met at position 139, But the CPs of P 1.2.3-pathotype PMMoVs from paprika showed Met to Asn substitution at the same position. This is the first report of identification of P 1.2.3 -pathotype PMMoV isolates from paprika in Korea.

Pepper mild mottle virus: a formidable foe of capsicum production—a review

“…A single amino acid mutation of asparagine to methionine at the 138th position (N138M) of the PMMoV-I isolate was sufficient to induce a hypersensitive response (HR) and localization of the virus in C. chinense plants with the L 3 gene (106). This mutation (N138M) is observed in all PMMoV isolates characterized as P 123 pathotypes (18,78,106,111). The mutations in PMMoV CP at the 7th position from alanine to serine (A7S), and the 81st position from serine to alanine (S81A) had L 3 -mediated resistance-inducing and -breaking abilities, respectively (112).…”

Complete Nucleotide Sequences and Genome Organization of Two Pepper Mild Mottle Virus Isolates from Capsicum annuum in South Korea

“…Tobamovirus strains isolated from pepper plants have been classified into four subgroups, P 0 , P 1 , P 1,2 and P 1,2,3 , on the basis of their responses with the corresponding resistance genes controlled by L 1 , L 2 , L 3 , and L 4 , which are considered to be alleles at the locus L ( 2 ). We described a resistance-breaking pathotype of PMMoV previously, designated PMMoV-P3, that overcomes the L 3 -mediated resistance in C. annuum and compared the pathogenicity of PMMoV-P3 in paprika cultivars with that of PMMoV-P2 (which overcomes the L 2 resistance) ( 3 , 4 ). To determine complete nucleotide sequences of PMMoV-P2 and -P3, viral RNAs isolated from purified virus particles using the SDS/Phenol/Proteinase K method ( 5 ) were used as templates for reverse transcription-PCR (RT-PCR) with four pairs of PMMoV-universial primers.…”