Citrus tristeza virus infection induces the accumulation of viral small RNAs (21–24-nt) mapping preferentially at the 3′-terminal region of the genomic RNA and affects the host small RNA profile

The Complex Genetics of Citrus tristeza virus

“…These could be from either pathogenic or asymptomatic phenotypes to limited or complete plant resistance [5]. Although most of these mechanisms are still a mystery, new discoveries towards the understanding of the genetics of CTV movement in the plant, host-range, host resistance and pathogenicity have been reported recently [19,20,21,62,63,64].…”

“…Although, CP, p20 and p23 have not been yet reported as suppressors of the citrus silencing mechanism, their presence in the CTV genome is in concordance with wide host range among citrus species and hybrids, previously described, and consequently, with the complexity of CTV-citrus interactions. In fact, in spite of the existence of these three silencing suppressors, accumulation of siRNAs in CTV-infected susceptible hosts is 50% of the total RNAs in the plant [64]. The CTV siRNAs accumulation in infected plants is directly proportional to the virus accumulation and varies depending on the citrus host.…”

“…The CTV siRNAs accumulation in infected plants is directly proportional to the virus accumulation and varies depending on the citrus host. Deep sequencing analysis of these siRNAs, from CTV-infected plants, indicated that they mainly consisted in small RNAs of 21-22 nt derived essentially from the CTV genome [64].…”

Molecular Virology and Pathogenicity of Citrus tristeza virus

“…The CTV genome contains three suppressors (CP, p20 and p23, see section 2) that block intracellular and/or intercellular RNA silencing mechanism in N. benthamiana and N. tabacumm plants (Lu et al, 2000). In spite of the presence of these three silencing suppressors, accumulation of siRNAs in CTV-infected susceptible hosts could be 50% of the total RNAs in the plant (Ruiz-Ruiz et al, 2011). Moreover, the siRNAs accumulation is directly proportional 287 to the virus accumulation and varies depending on the CTV strain and the citrus host (Comellas, 2009).…”

“…Moreover, the siRNAs accumulation is directly proportional 287 to the virus accumulation and varies depending on the CTV strain and the citrus host (Comellas, 2009). Deep sequencing analysis of siRNAs from CTV-infected plants indicated that they mainly consisted in small RNAs of 21-22 nt derived from essentially all the CTV genome (Ruiz-Ruiz et al, 2011). Although, CP, p20 and p23 have not been yet reported as RNAi suppressing genes in citrus, these three CTV genes could be candidates for symptom determinants.…”