African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12496

Full Length Research Paper

Characterization of three full Iris yellow spot virus genes of a garlic-infecting isolate from Zimbabwe using next-generation sequencing technology

Charles Karavina
  • Charles Karavina
  • Department of Plant Pathology, School of Agriculture, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Pietermaritzburg, South Africa.
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Jacques Davy Ibaba
  • Jacques Davy Ibaba
  • Department of Plant Pathology, School of Agriculture, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Pietermaritzburg, South Africa.
  • Google Scholar
Augustine Gubba
  • Augustine Gubba
  • Department of Plant Pathology, School of Agriculture, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Pietermaritzburg, South Africa.
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  •  Received: 28 December 2018
  •  Accepted: 29 January 2019
  •  Published: 31 October 2019

Abstract

Iris yellow spot virus (IYSV) is an important pathogen of Allium species worldwide. It has a tripartite genome consisting of the large (L), medium (M) and small (S) RNA segments. Despite its worldwide distribution, very few complete gene and genome sequences are available in public databases. The aim of this study was to obtain full gene sequences of a garlic-infecting IYSV isolate by next-generation sequencing (NGS) for understanding its evolution. Total RNA was extracted from an IYSV-positive garlic leaf and sequenced on the Illumina HiSeq platform using paired-end chemistry 125 × 125 bp reads. The quality of raw reads was assessed using FastQC software before trimming with Trimmomatic version 0.36. The resultant paired-end sequences were used for both de novo and reference-based genome assembly. The resultant consensus gene sequences were analyzed using SIAS (for sequence identity and composition), ExPASy (for protein molecular weight) and ORF Finder (for open reading frame identification). Three full gene sequences, that is, nucleocapsid (N), nonstructural protein (NSs) and movement protein (NSm) were recovered. The N gene did not display any distinct clustering patterns based on geographical locations and was most identical to an onion-infecting isolate from Serbia (Accession KT272878). The NSs and NSm genes clustered closely with homologous sequences of IYSV isolates that were retrieved from GenBank and EMBL. This study lays the foundation for complete genome studies of IYSV in Zimbabwe.

 

Key words: Allium species, emerging pathogen, reverse transcription polymerase chain reaction (RT-PCR), serology, tospovirus.