Comparision of peanut stripe virus isolates using symptomatology on particular hosta and serology

Serological tests using a direct antigen coating-indirect anti-Fc ELISA and antisera revealed interesting results. When lesional tissues of Chenopodium amaranticolor resulting from infection by various isolates were used as antigens, the reactions to a set of heterologous and homologous antisera could be classified into 5 serotypes. The Blotch and Mild isolates falled into Serotype-CI whereas Stripe, Chlorotic ring mottle and chlorotic line-pattern were in Serotype-CII. The Blotch-stripe and some isolates in the Mild group were in Serotype-CIII. The Necrotic and Blotch CP-N isolates were quite distinctive and could be put into 2 separated types: Serotype C IV and Serotype C V. The results correlated rather well with the grouping based on host disease reactions. Similar testing using antigens from groundnuts was less effective in differentiating the strains. The results also indicated that peanut chlorotic-ring mottle virus (PCRMV) was an isolates of peanut stripe virus but groundnut eye spot virus from Africa was different virus. Since all the isolates sent from japan are identical to PStV, it could be assumed that PStV has been in Southeast Asia as early as 1972 when the samples were collected from Thailand. The 24 isolates were brought back to Thailand in a dried leaf form and further studied serologically using SDS gel double diffusion test. All 24 isolates gave only a single precipitin band with no sign of spur when reacted to antisera to PCRMV, PStV-CR (Chlorotic ring isolatic ring isolate from Thailand) or Blackeye cowpea mosaic virus (BICMV). In fact from the serological reaction alone, PStV can not be distinguised from BICMV. But when reacted to an antiserum of soybean mosaic virus (SMV), the 24 isolates gave 2 different types of reaction. The isolates T1, T5, T6, T7, T9, A5, J3, I1, Id1, Id2 and P6 gave only 1 precipitin band when reacted with the antiserum while T2, T3, T4, T8, A4, A6, J1, J2, J4, I2, P4, P5, B2 and C gave 2 distinct bands. The majority of isolates that induced mild mottle, chlorotic ring mottle, necrotic and blotch-stripe appear to fall into type 1 group while the others are in type 2.