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Cucumber mosaic virus 2b proteins inhibit virus-induced aphid resistance in tobacco.

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Tungadi, Trisna 
Donnelly, Ruairí 
Iqbal, Javaid 


Cucumber mosaic virus (CMV), which is vectored by aphids, has a tripartite RNA genome encoding five proteins. In tobacco (Nicotiana tabacum), a subgroup IA CMV strain, Fny-CMV, increases plant susceptibility to aphid infestation but a viral mutant unable to express the 2b protein (Fny-CMV∆2b) induces aphid resistance. We hypothesized that in tobacco, one or more of the four other Fny-CMV gene products (the 1a or 2a replication proteins, the movement protein, or the coat protein) are potential aphid resistance elicitors, whilst the 2b protein counteracts induction of aphid resistance. Mutation of the Fny-CMV 2b protein indicated that inhibition of virus-induced resistance to aphids (Myzus persicae) depends on amino acid sequences known to control nucleus-to-cytoplasm shuttling. LS-CMV (subgroup II) also increased susceptibility to aphid infestation but the LS-CMV∆2b mutant did not induce aphid resistance. Using reassortant viruses comprising different combinations of LS and Fny genomic RNAs, we showed that Fny-CMV RNA 1 but not LS-CMV RNA 1 conditions aphid resistance in tobacco, suggesting that the Fny-CMV 1a protein triggers resistance. However, the 2b proteins of both strains suppress aphid resistance, suggesting that the ability of 2b proteins to inhibit aphid resistance is conserved among divergent CMV strains.



host manipulation, jasmonate, non-persistent, vector, viral suppressor of RNA silencing, virus transmission, Cucumovirus, Cyclopentanes, Oxylipins, RNA Interference, Nicotiana

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Mol Plant Pathol

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All rights reserved
Biotechnology and Biological Sciences Research Council (BB/J011762/1)
Leverhulme Trust (F/09 741/F)
Isaac Newton Trust (1207(1))
Biotechnology and Biological Sciences Research Council (BB/P023223/1)
This work was supported by grants from the UK Biotechnological and Biological Sciences Research Council (SCPRID grant number BB/J011762/1, and GCRF grant number BB/P023223/1) and the Leverhulme Trust (F/09741/F, RPG-2012-667), and QL was funded by the China Scholarship Council.