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.
Ochoa J, Valli A, Martín-Trillo M, Simón-Mateo C, García JA, Rodamilans B. Sterol isomerase HYDRA1 interacts with RNA silencing suppressor P1b and restricts potyviral infection. Plant Cell Environ 2019; 42: 3015-3026
Hervás M, Navajas R, Chagoyen M, Garcia JA, Martinez-Turiño, S. Phosphorylation-related cross-talk between distant regions of the core region of the coat protein contributes to virion assembly of Plum pox virus. . Mol Plant Microbe Interact 2020; 33: 653-667
González de Prádena A, Sánchez Jiménez A, San León D, Simmonds P, García JA, Valli AA. Plant virus genome is shaped by specific dinucleotide restrictions that influence viral infection. MBio 2020; 11: e02818-02819
A complex plant-virus interactive network modulates infectivity and symptom severity. Most plant viruses cannot infect all their potential hosts, and when they do, serious illness is not the norm, as revealed by recent metagenomic studies. Our laboratory studies this interaction network, which facilitates virus replication and propagation, but also induces plant defense responses and disease symptoms. Plum pox virus, our main subject of study, belongs to the family Potyviridae, the largest group of plant RNA viruses and causes sharka, a serious disease of stone fruit trees.
We are especially interested in defense responses related to RNA silencing and its viral suppressors. The typical silencing suppressor of potyvirids is HCPro, but the existence of additional silencing suppressors in different potyvirids, prompted us to suggest that escaping RNA silencing-mediated antiviral defenses is a powerful driving force of virus evolution. Potyvirid genomic RNAs are expressed through the synthesis of large polyproteins, processed by viral-encoded endopeptidases.
We are studying how host-specific modulation of this processing can contribute to potyviral pathogenicity and host range definition. Encapsidation of potyvirid genome is an active process. We have demonstrated a functional link between potyvirus RNA replication and virion assembly, and we are studying how posttranslational modifications of the capsid protein can contribute to sort the potyviral RNA into translation, replication or encapsidation. An important goal of our laboratory is applying our basic research results to control viral diseases through novel strategies. For instance, we are attenuating plant viruses by recoding their genomes in order to use them as cross-protection agents. We are also interested in developing other valuable biotools, such as a novel T-DNA delivery system, which can be used to efficiently inoculate plants with infectious viral cDNA clones, among other multiple applications.
