Identification and molecular characterization of a novel sugarcane streak mastrevirus and an isolate of the A-strain of maize streak virus from sugarcane in Nigeria

Abstract

Sugarcane and maize plants showing symptoms typical of those described for the so-called "African streak viruses" (AfSVs) were encountered during field surveys conducted from February to July 2015 to document viruses infecting both crops across the northern Guinea savannah region of Nigeria. As part of this study, two categories of complete mastrevirus-like genome sequences were obtained from nine samples (maize = 2; sugarcane = 7). In pairwise comparisons, the full-length genomes of the first sequence category (2,687 nt each; maize = 2; sugarcane = 2) shared 96 to 99% identity with global isolates of the A-strain of maize streak virus (MSV-A), indicating that sugarcane may also serve as a reservoir host to MSV-A. Analysis of the complete genomes belonging to the second sequence category (2,757 nt each; sugarcane = 5) showed that they shared 42 to 67% identity with their closest AfSV relatives, thus indicating that they represent sequences of a novel mastrevirus. Both sequence categories shared 61-62% sequence identity with each other. Further analysis revealed that the novel sugarcane-infecting virus, tentatively named as sugarcane chlorotic streak virus (SCSV), arose from a putative interspecific recombination event involving two grass-infecting mastreviruses, eragrostis streak virus and urochloa streak virus, as putative parental sequences. The results of this study add to the repertoire of diverse AfSVs present in cereal and sugarcane mixed cropping landscapes in the northern Guinea savannah region of Nigeria, with implications for disease epidemiology.

A survey on sugarcane mosaic symptoms leads to the first report of sugarcane chlorotic streak virus in Cameroon

“…ESV and USV are the closest mastreviruses to SCSV with 75-76% full genome identity, which is below the 78% demarcation threshold for Mastrevirus species. For undetermined reasons, these values for ESV and USV identity with SCSV are higher in our study as compared to the ones reported previously [4]. Furthermore, no signi cant recombination event was found in the SCSV genome of 17 isolates using RPD5 program, which differs also with the previous report on SCSV in Nigeria that described occurrence of one recombination in the CP gene [4].…”

“…If the presence of SCMV (one of the causal agents of mosaic disease with SrMV) was well known for several decades [13], this is to our knowledge the rst report of SCSV in Cameroon. The only other sugarcane growing location where this virus has been found so far is Nigeria, a border country of Cameroon [4]. The prevalence of SCSV in sugarcane commercial elds and the impact of this virus on crop yields are currently unknown.…”

“…Circular DNA molecules were ampli ed by rolling circle ampli cation (RCA) using the Phi29 DNA polymerase (TempliPhi™, GE Healthcare, USA) as previously described [19]. Two partially overlapping PCR primer pairs (SCSV_RepA_F 5'-CATAGTTCCAAACCTACAGCCT-3', SCSV_RepA_R 5'-ACTGCAACTTAGAGCCAGAGGC-3' and SCSV_IR_F 5'-GGCGCCAAGGACTATAAGATG-3', SCSV_IR_R 5'-TGCGATCCCACATACAAGCATC-3') were used to amplify the complete genome of SCSV isolates from Cameroon as reported by Yahaya et al [4]. Amplicons of approximatively 2700 bp obtained with both primer pairs were extracted from the electrophoresis agarose gel and puri ed (Monarch DNA Gel Extraction T1020L).…”

“…Sugarcane streak mosaic virus (SCSMV) is a poacevirus of the Potyviridae family that was recently discovered in Africa and leaves infected by this virus exhibit a mix of mosaic patterns and streaks [2]. Maize streak virus (MSV) is a mastrevirus from Africa that was initially discovered on maize but that also infects sugarcane in South Africa and in Nigeria [3,4]. Besides MSV, six other sugarcane-infecting mastreviruses have been reported in African locations or on the adjacent islands of the South West Indian Ocean [5,6], namely saccharum streak virus (SacSV) in South Africa [7], sugarcane chlorotic streak virus (SCSV) in Nigeria [4], sugarcane streak virus (SSV) in South Africa [8], sugarcane streak Egypt virus (SSEV) in Egypt [9], sugarcane white streak virus (SWSV) in Egypt, Sudan, Reunion Island and germplasm collections in Barbados and Guadeloupe [10][11][12], and sugarcane streak Reunion virus (SSRV) in Nigeria, Mauritius, and Reunion [9].…”

Prevalence of Viruses Infecting Sorghum in Nigeria-A Review

“…[50] used agroinfection to rapidly screen for MSV resistance in various maize genotypes. MSV can be detected using ELISA test kits and PCR [52,53]. A PCR-RFLP technique is being employed in differentiating the strains of MSV [54].…”