Abstract
Viral synergism is caused by co-infection of two unrelated viruses, leading to more severe symptoms or increased titres of one or both viruses. Synergistic infection of phloem-restricted poleroviruses and umbraviruses has destructive effects on crop plants. The mechanism underlying this synergy remains elusive. In our study, synergism was observed in co-infections of a polerovirus Brassica yellows virus (BrYV) and an umbravirus Pea enation mosaic virus 2 (PEMV 2) on Nicotiana benthamiana, which led to (1) increased titres of BrYV, (2) appearance of severe symptoms, (3) gain of mechanical transmission capacity of BrYV, (4) broader distribution of BrYV to non-vascular tissues. Besides, profiles of virus-derived small interfering RNAs (vsiRNAs) from BrYV and PEMV 2 in singly and doubly infected plants were obtained by small RNA deep sequencing. Our results showed that accumulation of BrYV vsiRNAs increased tremendously and ratio of positive to negative strand BrYV vsiRNAs differed between singly infected and co-infected plants. Positions to which the BrYV vsiRNAs mapped to the viral genome varied considerably during synergistic infection. Moreover, target genes of vsiRNAs were predicted and annotated. Our results revealed the synergistic characteristics during co-infection of BrYV and PEMV 2, and implied possible effects of synergism have on vsiRNAs.
Highlights
RNA silencing, a highly conserved mechanism in various eukaryotic organisms, regulates gene expression and plays a major role in antiviral immunity[1,2]
It has been reported that synergistic interaction between crinivirus Sweet potato chlorotic stunt virus (SPCSV) and begomovirus Sweet potato leaf curl virus isolate StV1 in sweet potato leads to specific changes in the relative abundance and distribution of SPCSV-derived siRNAs, implying a distinctive influence of begomoviruses on RNA silencing of SPCSV in synergy[29]
To examine whether synergism occurs between Brassica yellows virus (BrYV) and Pea enation mosaic virus 2 (PEMV 2), N. benthamiana plants at 3–4 leaf stage were agroinfiltrated with empty vector (Mock), BrYV, PEMV 2 and BrYV + PEMV 2, respectively
Summary
RNA silencing, a highly conserved mechanism in various eukaryotic organisms, regulates gene expression and plays a major role in antiviral immunity[1,2]. A typical trait of antiviral silencing in plants is production of virus-derived small interfering RNAs (vsiRNAs)[3,4,5]. For positive-strand plant RNA viruses, vsiRNAs are processed either from highly structured regions of viral genome or double-stranded viral RNA replication intermediates by Dicer-like (DCL) proteins[6,7]. These vsiRNAs are recruited by ARGONAUTE (AGO) containing RNA induced silencing complex (RISC) to guide them to the complementary viral RNAs or host transcripts in a sequence-specific manner[2,8,9,10]. It has been reported that synergistic interaction between crinivirus Sweet potato chlorotic stunt virus (SPCSV) and begomovirus Sweet potato leaf curl virus isolate StV1 in sweet potato leads to specific changes in the relative abundance and distribution of SPCSV-derived siRNAs, implying a distinctive influence of begomoviruses on RNA silencing of SPCSV in synergy[29]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.