Strains of Peanut Stripe Potyvirus Rapidly Identified by Profiling Peptides of the Virion Proteins

Virion proteins of five potyvirus isolates from groundnut in Thailand which induce a range of symptoms were compared with those from the type strains of peanut stripe potyvirus (PStV) and peanut mottle potyvirus (PeMoV). Profiles obtained by high performance liquid chromatography (HPLC) of tryptic peptide digests of the virion proteins of all five Thai isolates and PStV were very similar, whereas that of PeMoV was quite different. The results indicate that the Thai isolates are strains of PStV, and reaffirm the value of HPLC peptide profiling for rapidly identifying potyviruses.     

Tomato leaf curl geminivirus associated with cantaloupe yellow leaf disease in Thailand

Geminivirus associated with yellow leaf disease of cantaloupe plants was detected using polymerase chain reaction (PCR) with geminivirus-specific degenerate primers which anneal within the AC1 ORF (replication initiator protein gene) and the AV1 ORF (coat protein gene). A DNA fragment of 1.2 kbp was amplified, cloned and sequenced. The 32-base stem loop region was found in the amplified fragment. This included the conserved nonanucleotide sequence TAATATTAC present in all geminiviruses. The nucleotide sequence of the intergenic region (IR) was compared with 28 whitefly-transmitted geminiviruses. The geminivirus associated with yellow leaf disease of cantaloupe plants showed 96.2% sequence identity with DNA A of tomato leaf curl geminivirus from India (ToLCV-In2). These data suggest that cantaloupe yellow leaf disease was caused by ToLCV.