Juan Antonio García
Group Leader
Carmen Simón
Group Leader
Research summary
Plant viruses depend largely on host factors to replicate in the cell and to propagate throughout the plant and between individual plants. Plants in turn have developed antiviral defence mechanisms that must be counteracted by viral factors. These factors appear to be preferred targets for alternative plant defences. In our laboratory, we try to understand this complex interplay, mainly in the infection of the potyvirus Plum pox virus (PPV), the causal agent of sharka, a damaging disease of Prunus trees. We are especially interested in defence responses related to RNA silencing and its viral suppressors.
Publications
Pasin F, Bedoya LC, Bernabé-Orts JM, Gallo A, Simón-Mateo C, Orzaez D, García JA. Multiple T-DNA delivery to plants using novel mini binary vectors with compatible replication origins. ACS Synth Biol 2017 Oct 20;6(10):1962-1968
Gallo A, Valli A, Calvo M, García JA. A functional link between RNA replication and virion assembly in the potyvirus Plum pox virus. J. Virol. 2018; 92, e02179-17.
Martínez-Turiño S, Pérez JJ, Hervás M, Navajas R, Ciordia S, Udeshi ND, Shabanowitz J, Hunt DF, García JA. Phosphorylation coexists with O-GlcNAcylation in a plant virus protein and influences viral infection. Mol Plant Pathol 2017 Oct 11. doi: 10.1111/mpp.12626.
Shan H, Pasin F, Tzanetakis IE, Simón-Mateo C, García JA, Rodamilans B. Truncation of a P1 leader proteinase facilitates potyvirus replication in a non-permissive host. Mol Plant Pathol 2017 Nov 8. doi: 10.1111/mpp.12640.
A. Mingot, A. Valli, B. Rodamilans, D. San León, D.C. Baulcombe, J.A. García, J.J. López-Moya The P1N-PISPO trans-frame gene of Sweet potato feathery mottle potyvirus is produced during virus infection and functions as RNA silencing suppressor. J Virol. 2016; 90(7): 3543–3557
Plant viruses depend on host factors to replicate and to propagate throughout the plant and between individual plants. Plants in turn have developed antiviral defences, which must be counteracted by viral factors. These viral factors appear to be preferred targets for alternative plant defences. In our laboratory, we try to understand this complex interplay, mainly in infection by the potyvirus Plum pox virus (PPV), the causal agent of sharka, a damaging disease of Prunus trees.
We are interested in virus-host interactions that can help to define virus host range. We have demonstrated that single alterations in the 6K1 and CI proteins (corresponding to the cleavage site recognized by the viral protease NIa in the PPV polyprotein) are involved in alternative host adaptation of atypical PPV isolates to Nicotiana benthamiana and Prunus avium. These results suggest that fine regulation of polyprotein processing might depend on specific host factors and contribute to adaptation to specific hosts. By studying resistance of Arabidopsis thaliana and Chenopodium foetidum to cherry strain PPV isolates, we showed that defects in interactions between translation initiation factors and potyviral proteins might not only prevent infection in resistant varieties of susceptible host species, but also contribute to non-host resistance. We also demonstrated that self-cleavage of PPV P1 is negatively regulated by its highly disordered N-terminal region and relies on a specific host factor for its activation. Based on these results, we speculate that host-dependent regulation of P1/HCPro protease processing evolved to attenuate virus virulence and thus alleviate antiviral responses.
We apply the information obtained in our research to design control strategies for sharka and other viral diseases, and to develop PPV-based biotechnological tools. We have generated N. benthamiana transgenic lines that express different PPV-specific artificial miRNAs; they are being used to study the effectiveness and durability of antiviral resistance based on these small RNAs, and the side effects of the use of this technology on the virus evolutionary potential.
