Coat protein gene sequence based diagnosis of Groundnut bud necrosis virus Infection in Rajmash

A disease of rajmash characterized by chlorotic spots with irregular margins, veinal necrosis and slight distortion of leaf lamina was observed during post-rainy season (rabi) of 2009–10, 2010–11 and 2011–12. Plants infected at early stage remained stunted and finally collapsed. Disease incidence was between 4–5% in different fields. The causal virus was successfully sap transmitted from field infected plants to healthy plants of rajmash. The identity of the virus as Groundnut bud necrosis virus (GBNV) was confirmed by reverse transcription-polymerase chain reaction using primer pair (HRP26/HRP28) specific to the coat protein (CP) gene of the GBNv. Complete CP gene of rajmash isolate of GBNV was 831 nucleotides long. Sequence analysis of the CP gene revealed that the rajmash isolate under study (JN662492) shared maximum identity (98%) at both nucleotide as well as amino acids levels with GBNV-[Mung_ND] (AY871098) and GBNV-[Hya_Mah] (AY882004). The phylogenetic relationship analysis revealed that the present isolate of GBNV clustered with other isolates of GBNV. Thus, the virus causing disease in rajmash at Kanpur was identified as an isolate of GBNV and has been designated as GBNV-[Frb-KNP]. Full sequence of the CP gene of GBNV isolate infecting Phaseolus vulgaris is being reported here for the first time.