First report of Groundnut bud necrosis virus infecting wild species of Vigna, based on NP gene sequence characteristics

Abstract

Symptoms such as chlorotic and necrotic spots on leaves, necrosis of the stems and petioles, broadly resembling those induced by Groundnut bud necrosis virus (GBNV) in cultivated species of Vigna were observed in twelve accessions of wild species/sub-species of Vigna ( V. umbellata, V. glabrescens, V. hainiana, V. mungo var. mungo, V. radiata var. radiata and V. radiata var. sublobata ) grown at the Indian Institute of Pulses Research, Kanpur, India during August-November 2011. Disease incidence ranged between 7.13- 40.3%. The identity of the virus was confirmed on the basis of symptoms on diagnostic host (cowpea cv. Pusa Komal) and nucleocapsid protein ( NP ) gene sequence characteristics. Analysis of NP gene of intra-field isolates of GBNV revealed 1-4% diversity in nucleotide and 0-4% in amino acids. However, diversity among intra-field isolates and isolates from cultivated Vigna ranged 2-7% at nucleotide level and 0-6 at amino acids level. This paper reports for the first time GBNV infection in these wild species/sub-species of Vigna and analyze the intra-field diversity in the NP gene of 12 GBNV isolates.