Serological, Electron Microscopy, and Molecular Identification of Bean Yellow Mosaic Virus Naturally Infecting Canna Plants

Abstract

Bean yellow mosaic potyvirus (BYMV) is a highly destructive virus that inflicts significant economic damage on many important plants worldwide. It naturally infects numerous species of legumes as well as some non-leguminous plants, such as canna plants. The current study aimed to isolate and identify BYMV from naturally infected Canna plants and to produce BYMV polyclonal antibodies. The naturally infected Canna plants exhibiting typical streak mosaic patterns on the infected leaves, along with black spots grown in nurseries in the Alexandria governorate of Egypt, were collected. The BYMV virus was detected in infected Canna leaves sap by indirect ELISA and confirmed by RT-PCR via Cp-gene with an expected size of 525bp. The nucleotide sequence of BYMV-EG2 Cp-gene isolate recorded in NCBI under (Acc. No. PQ836641.1). BYMV isolate was transmitted in a non-persistent manner by Acyrthosiphon pisum, Aphis fabae, A. nerii and Brevicoryne brassicae, with average transmission rates of 66.7, 75, 33.3, and 50 % respectively. The partially purified virus using polyethylene glycol (PEG) 6000 and ultra-centrifugation have purity A260/280 ratio was 1.17, and the Amax/min ratio was 0.85. The virus yield was 13.8 mg/100 g of fresh weight infected faba bean leaves. The immunogenicity of the virus isolate produced an antiserum titer was to 1:1.28x105 determined by indirect ELISA. The transmission electron microscopy revealed that circular inclusions were formed by the extension of pinwheel circles in Canna leaves. The TEM highlighted flexible rod-shaped particles of BYMV measuring approximately 740 nm in length by the negatively stained method with phosphotungstic acid.