Complete genome sequences of two distinct and diverse Citrus tristeza virus isolates from New Zealand

Abstract

Two Citrus tristeza virus (CTV) isolates from New Zealand that display distinct phenotypes were isolated, examined and sequenced in full. The first isolate, NZ-M16, is largely asymptomatic and non-transmissible by the aphid vector Toxoptera citricida, while the second, NZ-B18, is highly transmissible and induces very severe symptoms on C. sinensis and C. aurantii. Phylogenetic analysis of the genome sequences showed that both isolates were approximately 90-93% similar to the VT and T318 isolates but possessed only 89% identity to one another. Based on sequence identity, both isolates are VT subtypes, with NZ-M16 being T3-like, while NZ-B18 is a member of a novel subtype with B165 from India.

One Step RT-PCR Method for Quick and Reliable Detection of Citrus tristeza virus (CTV) in Mid-Hills of Meghalaya

“…Harper et al, (2009) also used both one step and two-step reverse transcription-polymerase chain reaction (RT-PCR) for the detection of CTV in New Zealand. Gillings et al, (1993) used the RT-PCR by using a one-step RT-PCR kit (QIAGEN) by following the manufacturers protocol.…”

The Complex Genetics of Citrus tristeza virus

“…Actually, there are twenty CTV genomic sequences available. These are T36 and T30 from Florida [2,27]; VT from Israel [28]; SY568R from California [29,30]; T385 and T318A from Spain [31,32]; NuagA from Japan [33]; Qaha (AY340974) from Egypt; Mexican isolate (DQ272579); B165 form India [34]; NZ-M16, NZ-B18, NZRB-TH28, NZRB-TH30, NZRB-M12, NZRB-M17 and NZRB-G9 from New Zealand [35,36]; HA16-5 and HA18-9 from Hawaii [37] and Kpg3 from China [38]. Genetic comparison of these CTV genomes revealed an extreme genomic divergence for genotypes of the same viral species (Figure 3).…”

Molecular Virology and Pathogenicity of Citrus tristeza virus

“…These genomic sequences are T36 and T30 from Florida, USA (Albiach-Martí et al, 2000b;Karasev et al, 1995); VT from Israel ; SY568R from California (Z.N. Vives et al, 2005); T385 and T318A from Spain (Ruiz-Ruiz et al, 2006;Vives et al, 1999); NuagA from Japan (Suastika et al, 2001); Qaha (AY340974) from Egypt; Mexican isolate (DQ272579); B165 from India ; NZ-M16, NZ-B18, NZRB-TH28, NZRB-TH30, NZRB-M12, NZRB-M17 and NZRB-G9 from New Zealand (Harper et al, 2009(Harper et al, , 2010; and HA16-5 and HA18-9 from Hawaii (Melzer et al, 2010). Comparison of CTV genomes yielded nucleotide identities from 79.9% (between Qaha and VT) to 99.3% (between T30 and T385) (Melzer et al 2010).…”

“…Comparison of CTV genomes yielded nucleotide identities from 79.9% (between Qaha and VT) to 99.3% (between T30 and T385) (Melzer et al 2010). Phylogenetic analysis grouped the CTV genome diversity in seven clades reflecting six main severe sequence-related groups [(1) T36-like (T36, Qaha, Mexican); (2) the NZRB strains plus HA18-9; (3) the VT-like (VT, NUagA, T318A, SY568); (4) HA16-5; (5) B165 and NZ-B18; (6) NZ-M16] and one asymptomatic genotype [the T30-like (T30 ,T385)] (Harper et al, 2009;Melzer et al 2010). Moreover, the T36-like genotypes and close relatives [clades (1) and (2)] show an unusually high genetic distance to the other CTV genotypes in spite of belonging to the same taxonomic entity.…”

“…In this case, the degree of CTV symptomology ranges from the mild phenotypes, which are almost asymptomatic, to the www.intechopen.com Viral Genomes -Molecular Structure, Diversity, Gene Expression Mechanisms and Host-Virus Interactions 286 highly virulent CTV isolates that could kill the plant . However, there are exceptions, such as severe isolates that induce symptoms in sweet orange but not in Mexican lime (Harper et al, 2009). …”