Abstract
The olive tree (Olea europaea L.) was one of the first plant species in history to be domesticated. Throughout olive domestication, gene expression has undergone drastic changes that may affect tissue/organ-specific genes. This is an RNA-seq study of the transcriptomic activity of different tissues/organs from adult olive tree cv. “Picual” under field conditions. This analysis unveiled 53,456 genes with expression in at least one tissue, 32,030 of which were expressed in all organs and 19,575 were found to be potential housekeeping genes. In addition, the specific expression pattern in each plant part was studied. The flower was clearly the organ with the most exclusively expressed genes, 3529, many of which were involved in reproduction. Many of these organ-specific genes are generally involved in regulatory activities and have a nuclear protein localization, except for leaves, where there are also many genes with a plastid localization. This was also observed in stems to a lesser extent. Moreover, pathogen defense and immunity pathways were highly represented in roots. These data show a complex pattern of gene expression in different organs, and provide relevant data about housekeeping and organ-specific genes in cultivated olive.
Highlights
The olive tree (Olea europaea L.) was one of the first plant species to be domesticated in history.The demand of olive oil and extra virgin olive oil (EVOO), which is the main product obtained from this crop, is continuously increasing, and its health benefits are well-established
The high number of genes in the cultivated olive genome can be a consequence of two rounds of tetraploidy described in the evolution of the Olea genus. These events of tetraploidy have been dated around 57–63 million years ago (Mya) and 26–30 Mya by analyzing the wild olive genome [5], and around 62 Mya and
The RNA-seq transcriptomic analysis of the fruit, flower, leaf, meristem, root, and stem samples from adult healthy plants revealed the expression of 53,456 unique genes, which means that there are nearly 25,000 genes in the genome that might be expressed in other developmental stages in response to biotic or abiotic stresses, or silenced
Summary
The olive tree (Olea europaea L.) was one of the first plant species to be domesticated in history.The demand of olive oil and extra virgin olive oil (EVOO), which is the main product obtained from this crop, is continuously increasing, and its health benefits are well-established. The olive tree (Olea europaea L.) was one of the first plant species to be domesticated in history. The EVOO from cultivar “Picual” has exceptional organoleptic properties and marked oxidative stability due to its high content in polyphenolic compounds [1,2]. “Picual” is one of the most important olive varieties worldwide and represents 50% of all the olives trees in Spain, and approximately 20% in the world [3]. Olive tree breeding is a process that requires decades and has been limited by the genetic knowledge about this plant species being scarce until very recently. The development of genomic information and tools for breeders should be possible because the genomes of wild olive trees Knowing whether all the paralog genes are expressed or one or a few of them, or if they present a differential expression pattern depending
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