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ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Crop and Product Physiology

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1682101

This article is part of the Research TopicOlive Science - Volume IIView all articles

From Juvenile to Adult: Investigating miRNAs, Gene Expression, and the Juvenile Cone in Olive Development

Provisionally accepted
Paola  Romero-RodríguezPaola Romero-Rodríguez1Ana  GordonAna Gordon2Esteban  MecaEsteban Meca3Carmen  Tercero AlcázarCarmen Tercero Alcázar1Galen  T MartinGalen T Martin4María Teresa  García LópezMaría Teresa García López1Juan  MoralJuan Moral1Brandon  S GautBrandon S Gaut4Concepción  Munoz DiezConcepción Munoz Diez1*
  • 1Department of Agronomy, University of Cordoba, Córdoba, Spain
  • 2Department of Cellular Biology, Physiology and Immunology, University of Cordoba, Córdoba, Spain
  • 3Department of Applied Physics, Radiology and Physical Medicine, University of Cordoba, Córdoba, Spain
  • 4University of California Irvine Department of Ecology and Evolutionary Biology, Irvine, United States

The final, formatted version of the article will be published soon.

The long juvenile phase in perennials hinders rapid breeding, highlighting the need for early selection markers. Some species, such as the olive tree (Olea europaea L.), develop a juvenile cone, where adult tissue forms in the upper and peripheral canopy, while basal and inner regions remain juvenile. These structures offer a unique, yet underexplored, system for studying the juvenile-to-adult transition while minimizing genetic and environmental variability. We analyzed tissues from trees with a juvenile cone to identify genes and miRNAs distinguishing juvenile from adult vegetative tissue. Known transition markers, including miR156, miR172, and homologs of APETALA2 and AGAMOUS-like 42, showed clear differential expression across developmental stages, with the miR156/miR172 ratio being particularly discriminatory. In contrast, DNA methylation patterns showed few differences between juvenile and adult leaves, and differentially expressed genes were not enriched for methylation changes. Our findings show that the juvenile cone represents an intermediate developmental stage and provides a unique system for studying phase transitions in perennials. Identified miRNA and gene markers not only improve our understanding of olive development but also offer practical tools to facilitate the selection of rapid-maturing genotypes in olives and other perennials, such as pistachio (Pistacia vera L.). Overall, the juvenile cone serves as a valuable model for developmental analyses, and our findings provide a framework to enhance breeding efficiency in olives and other perennial fruit species.

Keywords: juvenile-to-adult transition, MicroRNAs, qPCR, high throughput sequencing, methylome, Selection markers, Breeding

Received: 08 Aug 2025; Accepted: 02 Oct 2025.

Copyright: © 2025 Romero-Rodríguez, Gordon, Meca, Tercero Alcázar, Martin, García López, Moral, Gaut and Munoz Diez. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Concepción Munoz Diez, cmdiez@uco.es

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