The entry of cucumber mosaic virus into cucumber xylem is facilitated by co-infection with zucchini yellow mosaic virus

Abstract

We investigated the synergistic effects of co-infection by zucchini yellow mosaic virus (ZYMV) and cucumber mosaic virus (CMV) on viral distribution in the vascular tissues of cucumber. Immunohistochemical observations indicated that ZYMV was present in both the phloem and xylem tissues. ZYMV-RNA was detected in both the xylem wash and guttation fluid of ZYMV-inoculated cucumber. Steam treatment at a stem internode indicated that ZYMV enters the xylem vessels and moves through them but does not cause systemic infection in the plant. CMV distribution in singly infected cucumbers was restricted to phloem tissue. By contrast, CMV was detected in the xylem tissue of cotyledons in plants co-infected with CMV and ZYMV. Although both ZYMV-RNA and CMV-RNA were detected in the xylem wash and upper internodes of steam-treated, co-infected cucumbers grown at 24 °C, neither virus was detected in the upper leaves using an ELISA assay. Genetically modified CMV harboring the ZYMV HC-Pro gene was distributed in the xylem and phloem tissues of singly inoculated cucumber cotyledons. These results indicate that the ZYMV HC-Pro gene facilitates CMV entry into the xylem vessels of co-infected cucumbers.

Ultrastructural Analysis of Prune Dwarf Virus Intercellular Transport and Pathogenesis

“…The systemic transport of PDV seems to occur equally in sieve tubes and xylem vessels, as shown by us in tobacco [ 33 ]. Similar results were observed in natural hosts.…”

The P1 Protein of Watermelon mosaic virus Compromises the Activity as RNA Silencing Suppressor of the P25 Protein of Cucurbit yellow stunting disorder virus

“…On the other hand, there are no specific studies on the distribution of WMV within different tissues and cells in the plant, but comparing to other potyviruses it was expected to invade more cell types (Kogovsek et al, 2011). As a further complication, the distribution of viruses in mixed and individual infections could be different, as it was shown for instance in combinations of potyvirus and cucumovirus (Ryang et al, 2004;Mochizuki et al, 2016). Interestingly, in sweet potato plants co-infected by SPCSV and potyviruses, crinivirus components were detected outside the phloem, in contrast with its restricted phloem localization in single infections (Nome et al, 2007).…”

Blaze a New Trail: Plant Virus Xylem Exploitation

“…To date, at least 39 plant viruses have been reportedly found in the xylem-associated cells of many different hosts, including herbaceous and perennial woody plants ( Table 1 ). Interestingly, the majority of xylem-invading viruses (35/39) studied to date belong to the group of positive-sense single-stranded RNA (+ssRNA) viruses in the following families: Alphaflexiviridae , Benyviridae , Bromoviridae , Closteroviridae , Potyviridae , Secoviridae , Sobemoviridae , Tombusviridae , and Virgaviridae ( Table 1 ) [ 6 , 7 , 8 , 10 , 11 , 12 , 13 , 14 , 16 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Other viruses are three single-stranded DNA (ssDNA) viruses in the family of Geminiviridae [ 37 ] and a negative-sense RNA virus in the family Rhabdoviridae ( Table 1 ) [ 9 ].…”

“…In one experiment, a portion of a cucumber stem was steam-treated, followed by inoculation with Zucchini yellow mosaic virus (ZYMV) at a site beneath the treated area. The detection of the virus in the xylem of the upper leaves demonstrated that ZYMV could enter xylem vessels and move [ 6 ]. Stem steam-treatments in other herbaceous host–virus pathosystems, which included Turnip mosaic virus (TuMV) in the Nicotiana benthamiana Domin [ 8 ], and Southern bean mosaic virus (SBMV) in the pinto bean ( Phaseolus vulgaris L.) [ 26 , 28 ], resulted in similar findings.…”

“…With that, the xylem seems to be a challenging territory for the plant viruses and an unlikely area to serve for virus occupation. Interestingly, a growing number of studies, especially those in more recent years, point to the importance of the relationship between the vascular xylem in the plant host–virus interactions and disease production [ 6 , 7 , 8 ]. Viruses do find ways out to blaze trails in the xylem, as they constantly evolve and adapt to environmental challenges.…”