1. Claim 1: a method for improving the resistance of plants to RNA virus, wherein the method comprises the use of only one RNA mutant enzyme of protein (hereinafter referred to as cytorp) in the factory,and where the aforementioned CytoRP: is a protein-only RNase P enzyme that neither comprises a nuclear localization signal domain (NLS) nor a sequence domain that seeks access to organelles (MTS) and has the ability to cleave the similar structure to that of tRNA (TLS) in 3 of a plant RNA virus. Claim 2: The method according to claim 1, characterized in that said protein RNase P enzyme only contains residues G254, G255, G256, C281, C284, E339, D343, D421, D422, D440, D444, H445, M477 , S482, W493, H494, P496, C511 and R514,According to the prorp2 serial number of A.thaliana, the code is ID sec.105. Claim 9: a separate polynucleotide that encodes a cytorp as defined in any of claims 1 to 7. Claim 12: a host unit characterized by a recombinant expression band as defined in claim 10 or a recombinant vector as defined in claim 11. Claim 15: a transgenic plant that can be obtained by the method of claim 14, i.e. the transgenic plant, has the recombinant expression band defined in claim 10.Reivindicación 1: Un método para aumentar la resistencia de una planta a un virus de ARN de vegetales, donde el mencionado método comprende la expresión, en la mencionada planta, de una enzima RNasa P mutante solamente de proteínas (de ahora en adelante denominada CytoRP), y donde la mencionada CytoRP: es una enzima RNasa P solamente de proteínas que ni comprende un dominio de señales de localización nuclear (NLS) ni un dominio de secuencias que buscan acceso a las organelas (MTS) y tiene la capacidad de escindir la estructura similar a la del ARNt (TLS) en 3 de un virus de ARN de vegetales. Reivindicación 2: El método según la reivindicación 1, que se caracteriza porque la mencionada enzima RNasa P solamente de proteínas contiene los residuos G254, G255, G256, C281, C284, E339, D343, D4
