Nature Biotechnology
19, 263 - 267 (2001)
doi:10.1038/85719
Constitutive expression of Arabidopsis LEAFY or APETALA1 genes in citrus reduces their generation timeLeandro Peña1, Mar Martín-Trillo2, 3, José Juárez1, José A. Pina1, Luis Navarro1
& José M. Martínez-Zapater2, 31
Departamento de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Moncada, 46113 Valencia, Spain. 2
Departamento de Mejora Genética y Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de La Coruña km7, 28040 Madrid, Spain. 3
Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus de la Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Correspondence should be addressed to José M. Martínez-Zapater zapater@cnb.uam.esCitrus trees have a long juvenile phase that delays their reproductive development by between 6 and 20 years, depending on the species. With the aim of accelerating their flowering time, we transformed juvenile citrus seedlings to constitutively express the Arabidopsis LEAFY (LFY) or APETALA1 (AP1) genes, which promote flower initiation in Arabidopsis. Both types of transgenic citrus produced fertile flowers and fruits as early as the first year, notably through a mechanism involving an appreciable shortening of their juvenile phase. Furthermore, expression of AP1 was as efficient as LFY in the initiation of flowers, and did not produce any severe developmental abnormality. Both types of transgenic trees flowered in consecutive years, and their flowering response was under environmental control. In addition, zygotic and nucellar derived transgenic seedlings had a very short juvenile phase and flowered in their first spring, demonstrating the stability and inheritance of this trait. These results open new possibilities for domestication, genetic improvement, and experimental research in citrus and other woody species.
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