Tulip chlorotic blotch virus, a second potyvirus causing tulip flower break

Abstract

SUMMARYTulip chlorotic blotch virus (TCBV), an apparently undescribed potyvirus found in field grown tulips in Australia, causes symptoms in tulip leaves and flowers identical to those induced by tulip breaking virus (TBV). TCBV was transmitted mechanically to 14 of 34 species in four of 13 families. Nicotiana clevelandii is a suitable propagation host and Chenopodium amaranticolor a local‐lesion assay host. TCBV was transmitted from tulip to tulip and TV. clevelandii by the aphid Myzus persicae. Unlike TBV it was not transmitted to Lilium formosanum either by M. persicae or by manual inoculation.Leaf extracts from TCBV‐containing TV. clevelandii were infective after dilution to l0‐3 but not 10‐4 and after heating for 10 min at 50°C but not 60°C; infectivity and particle recovery were adversely affected by freezing at ‐20°C. TCBV particles were purified (c. 1 mg/100g g N. clevelandii leaf) from tissue extracts in 0·3 M citrate buffer containing 10 mM EDTA and 0·2% (v/v) 2‐mercaptoethanol at pH 7·4 by clarification with 8·5% (v/v) n‐butanol followed by differential centrifugation and sucrose density gradient centrifugation. Purified particles measured c. 720 × 12 nm. Virus particle antigen was readily detected in leaf and tepal extracts of tulip by enzyme‐linked immunosorbent assay. A distant serological relationship was found between particles of TCBV and those of bean yellow mosaic virus but no serological relationship was found to TBV or four other potyviruses.