The present invention describes the compositions of the pine lactone and zeatin secondary metabolites resulting from extracts of the pine root, which stimulate and promote the gene Pthik1 expression, this gene encoding for a hystidine kinase and being isolated from the ectomycorrhizal fungi Pisolithus tinctorius. Said gene forms part of a system of two components able to sense the pine lactone and zeatine root exudates, which allow a symbiotic association or ectomycorrhizal process to start. Since the ectomycorrhizal process is slow, the compositions of the invention facilitate and accelerate said process, thus being used in reforestation systems for commercial purposes, in the formation of forest plantations or soil recovery plantations, the plantation of timber producing species, ornamental trees and trees producing fruits in a reduced time, as well as for protecting basins or in genetic improvement programs.La presente invención un método para inducir ectomicorrización en plantas, caracterizado porque comprende las etapas de: a) Transfectar una cepa de un hongo ectomicorrízico con cDNA que codifique para la proteína histidina cinasa y promover la expresión de dicho cDNA en el hongo, b) Inocular a las plantas de interés, el hongo obtenido enla etapa a) y, c) cultivar las plantas. Una molécula de ácido nucelico para inducir ectomicorrización en plantas, caracterizada porque tiene la SEQ ID NO.2.
