Molecular comparative analysis of component 1 (DNA-R) of an Egyptian isolate of banana bunchy top nanovirus isolated from banana aphid (Pentalonia nigronervosa)

Abstract

We are reporting a molecular comparative analysis of component 1 BBTV-DNA-R of an Egyptian isolate of (BBTV) and 30 different geographical isolates. DNA was extracted from BBTVinfected adult banana aphids collected from El-Qalubia Governorate, Egypt. Using specific primers the BBTV-DNA-R was amplified, cloned into a prokaryote vector, sequenced and a molecular comparative analysis of BBTV-DNA-R of this study and some overseas isolates of BBTV-infected banana plants was determined. Results showed that the component 1 consists of 1108 nts and contains a sequence of 69 nts representing the CR-SL of 31 nts. A CR-M (90 nts) at the position (972-1062) characterized with GC-rich sequence from nts 76 to 90 (average of 80% G + C) was found. Alignment results of BBTV DNA-R confirmed the presence of a number of conserved regions in all isolates. Large ORF of 861 nts at position 102 to 962 in the virion sense were detected. The predicted protein of this ORF consisted of 286 amino acids and had a molecular weight of 33.8 kDa. The DNA-phylogenetic analysis showed a percent identity of 98.0 and 97.9 between BBTV DNA-R and isolates of Pakistan (isolate TJ1) and Australia (isolate V1), respectively. The similarities between the gene product of Egyptian BBTV DNA-R and the 30 overseas isolates ranged from 93.7 to 99.0%. Differences in phylogenetic trees based on the entire sequence of BBTV DNA-R, CR-M and amino acid sequences confirmed the existence of two taxonomic groups of BBTV and the Egyptian isolate belongs to the south pacific group.

Molecular Characterization of Isolates of the Banana Bunchy Top Virus (BBTV) from the District of Chókwè, Mozambique

“…These results were corroborated by the distribution of the isolates in the phylogenetic tree based on nucleotide sequences, which showed a clear subdivision of the isolates into two distinct clades, with all the Mozambican isolates grouped together with the isolates of the PIO group. Other authors studying isolates from different African countries also reported that the isolates belonged to the PIO group [21,37,38,[40][41][42][43].…”

RNAi technology for management of banana bunchy top disease

“…The genome of BBTV is multipartite, comprising of six circular components (Figure 2) with an approximate size of 1.1 kb each (Burns, Harding, & Dale, 1995; Harding, Burns, & Dale, 1991; Harding, Burns, Hafner, Dietzgen, & Dale, 1993) and are known to promote the pathogenicity of the virus. They were initially named as DNA 1–6 but recently named as DNA‐R, DNA‐U3, DNA‐S, DNA‐M, DNA‐C, and DNA‐N, respectively (Abdel‐Salam, Dahot, & Sadik, 2012; Harding et al., 1991; Wu, You, & Soong, 1994). The six components are encapsidated within separate virions, each about 18–20 nm in diameter (Harding et al., 1993).…”

“…DNA‐R encodes a replication initiation protein (Rep) responsible for initiating viral DNA replication, DNA‐S encodes the coat protein (CP), DNA‐C encodes the cell‐cycle link protein (Clink), DNA‐M encodes the movement protein (MP), and DNA‐N encodes the nuclear shuttle protein (NSP), while the function of DNA‐U3 is unknown (Abdel‐Salam et al., 2012; Burns et al., 1995; Wanitchakorn, Hafner, Harding, & Dale, 2000; Wanitchakorn, Harding, & Dale, 1997). BBTV DNA‐R, DNA‐U3, DNA‐S, DNA‐M, DNA‐C, and DNA‐N (DNA‐1–DNA‐6) have been consistently associated with BBTV isolates globally, suggesting they are integral components of the BBTV genome.…”

Phylogenetic analysis and molecular characterization of BBTV DNA-R of wild and cultivated banana isolates from East Java, Indonesia

“…It is an icosahedral virus consisting of six circular single-stranded DNA genome components i.e., DNA-R, DNA-U3, DNA-S, DNA-M, DNA-C and DNA-N (previously named DNA-1 to DNA-6, respectively) (Elayabalan et al 2015). The sequences length of each genome component is approximately 1 to 1.1 Kb, and the transcripts have been mapped (Abdel-Salam et al 2012). DNA-R encodes a master replication-associated protein (rep), DNA-S a capsid protein (cp), DNA-M a movement protein (mp), DNA-C a cell-cycle link protein (Clink), and DNA-N a nuclear shuttle protein (nsp) gene.…”