Characterization of the expression patterns of LEAFY/FLORICAULA and NEEDLY orthologs in female and male cones of the conifer genera Picea, Podocarpus, and Taxus: implications for current evo-devo hypotheses for gymnosperms

Authors

  • Alejandra Vázquez-Lobo,

    1. Departamento de Ecología Evolutiva, Instituto de Ecología, UNAM AP 70–275 México DF 04510, Mexico
    2. Evolutionary Biology Centre, Physiological Botany, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
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  • Annelie Carlsbecker,

    1. Evolutionary Biology Centre, Physiological Botany, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
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  • Francisco Vergara-Silva,

    1. Evolutionary Biology Centre, Physiological Botany, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
    2. Departamento de Biología Evolutiva, Instituto de Ecología, A. C., Km. 2.5 Carretera Antigua a Coatepec 351, Congregación El Haya, Xalapa 91070, Veracruz, Mexico
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  • Elena R. Alvarez-Buylla,

    1. Departamento de Ecología Funcional, Instituto de Ecología, UNAM. AP 70–275, México DF 04510, Mexico
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  • Daniel Piñero,

    1. Departamento de Ecología Evolutiva, Instituto de Ecología, UNAM AP 70–275 México DF 04510, Mexico
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  • Peter Engström

    Corresponding author
    1. Evolutionary Biology Centre, Physiological Botany, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
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*Author for correspondence (email: peter.engstrom@ebc.uu.se)

Abstract

SUMMARY The identity of genes causally implicated in the development and evolutionary origin of reproductive characters in gymnosperms is largely unknown. Working within the framework of plant evolutionary developmental biology, here we have cloned, sequenced, performed phylogenetic analyses upon and tested the expression patterns of LEAFY/FLORICAULA and NEEDLY orthologs in reproductive structures from selected species of the conifer genera Picea, Podocarpus, and Taxus. Contrary to expectations based on previous assessments, expression of LFY/FLO and NLY in cones of these taxa was found to occur simultaneously in a single reproductive axis, initially overlapping but later in mutually exclusive primordia and/or groups of developing cells in both female and male structures. These observations directly affect the status of the “mostly male theory” for the origin of the angiosperm flower. On the other hand, comparative spatiotemporal patterns of the expression of these genes suggest a complex genetic regulatory network of cone development, as well as a scheme of functional divergence for LFY/FLO with respect to NLY homologs in gymnosperms, both with clear heterochronic aspects. Results presented in this study contribute to the understanding of the molecular-genetic basis of morphological evolution in conifer cones, and may aid in establishing a foundation for gymnosperm-specific, testable evo-devo hypotheses.

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