Brief report of the construction of infectious DNA clones of South African genetic variants of grapevine virus A and grapevine virus B.

D E Goszczynski

doi:10.1186/s40064-015-1517-2

Abstract

BackgroundRecent research results strongly suggest that certain genetic variants of grapevine virus A (GVA) and grapevine virus B (GVB), two members of the Vitivirus genus of the family Betaflexiviridae, are the cause of Shiraz disease and corky bark disease of grapevines in South Africa, respectively. To investigate this hypothesis, work was undertaken to construct DNA clones of these viruses.Findings and conclusionsBiologically viable and stable DNA clones of genetic variants of GVA and GVB B from South Africa were constructed. The clones share 76.3, 73.2 and 85.2, 77.6 % nt sequence similarity with corresponding clones constructed in Italy and Israel. The results suggest that a derivative of a mini binary vector pCB302 is superior to pCAMBIA1305.1 for the construction of infectious and stable DNA clones of vitiviruses. Successful construction of such DNA clones of GVA and GVB reported in this study is a clear step towards fulfilling Koch’s 3rd postulate in investigating the aetiology of Shiraz disease and corky bark disease.

Highlights

Recent research results strongly suggest that certain genetic variants of grapevine virus A (GVA) and grapevine virus B (GVB), two members of the Vitivirus genus of the family Betaflexiviridae, are the cause of Shiraz disease and corky bark disease of grapevines in South Africa, respectively
The cauliflower mosaic virus (CaMV) Ca35S promoter was amplified from binary plasmid pCAMBIA1305.1, and linked to DNA fragment complementary to the 5′ end of the virus genome in PCR described by Peremyslov and Dolja (2007)
Full genome DNA copies of both GVA P163-M5 and GVB 953-1 under 35S promoter cloned into pGEM-T vector could be found among transformants of E. coli

Summary

Introduction

Recent research results strongly suggest that certain genetic variants of grapevine virus A (GVA) and grapevine virus B (GVB), two members of the Vitivirus genus of the family Betaflexiviridae, are the cause of Shiraz disease and corky bark disease of grapevines in South Africa, respectively. For the construction of DNA clones reported in this paper, genetic variants GVA P163-M5 and GVB 953-1, sharing only 76.3 %, 73.2 % and 85.2 %, 77.6 % nt genome similarity with the corresponding viruses from Italy and Israel, were used (Fig. 1).

Results

Conclusion