Fuente: WIPO "tomato" A method and application for cultivating a Huanglongbing-resistant plant is provided. CsPUB21 attenuates a defense response of citrus based on terpene compounds through direct ubiquitination and degradation of a CsMYC2 protein. Resistance of citrus to a pathogen CLas and a spread vector thereof, i.e. Asian Diaphorina citri Kuwayama, can be improved by silencing of a CsPUB21 gene. Infestation of the pathogen CLas can be reduced by overexpression of CsPUB21DN, a dominant negative mutant of PUB21. Additionally, the CLas concentration in leaves of a susceptible plant can be effectively reduced by artificially replacing an amino acid Cys (TGC) at position 39 of a key enzyme activation site of CsPUB21 in the susceptible plant with Ala (GCC) via gene editing. This method and application provide a means to effectively resist the replication and spread of Huanglongbing pathogens, which cause citrus greening.