Cork oak is the main cork-producing species worldwide, and plays a significant economic, ecological and social role in the Mediterranean countries, in particular in Portugal and Spain. The ability to produce cork is limited to a few species, hence it must involve specific regulation mechanisms that are unique to these species. However, to date, these mechanisms remain largely understudied, especially with approaches involving the use of high-throughput sequencing technology. In this study, the transcriptome of cork-producing and non-cork-producing Quercus cerris × suber hybrids was analyzed in order to elucidate the differences between the two groups of trees displaying contrasting phenotypes for cork production. The results revealed the presence of a significant number of genes exclusively associated with cork production, in the trees that developed cork. Moreover, several gene ontology subcategories, such as cell wall biogenesis, lipid metabolic processes, metal ion binding and apoplast/cell wall, were only detected in the trees with cork production. These results indicate the existence, at the transcriptome level, of mechanisms that seem to be unique and necessary for cork production, which is an advancement in our knowledge regarding the genetic regulation behind cork formation and production.
Cork oak Transcriptome Cork production Hybrids
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This study was funded by Fundação para a Ciência e a Tecnologia (FCT) projects Cork Oak EST Consortium SOBREIRO/0017/2009 and UID/AGR/00115/2013. Financial support for AMR, AU and PB was provided by Investigador FCT project IF/00574/2012/CP1209/CT0001: “Genetic characterization of national animal and plant resources using next-generation sequencing”. Financial support for AMF was provided by projects PEst-OE/BIA/UI4046/2011 and FCT Investigator IF/00169/2015.
This study was conceived by IC, RC, AMF, RT, SG and FN (coordinator). Collection and identification of field material was performed by IC, RC and FN. Sample preparation and nucleic acid isolation were performed by RC and FN. qPCR validations were executed by AF and SG. Bioinformatics data analyses were conducted by BM, AU, PB, IC and AMR. Biological interpretation of the results was conducted by BM, AU, AMR, AMF, IC and FN. The manuscript was written by BM, AU, FN and AMR. All authors read and approved the final manuscript.
Sequence reads were deposited in the NCBI Sequence Read Archive (SRA) under the accession numbers ERX143070 and ERX143071, for the normalized libraries, and SRX2677031 and SRX2677030, for the non-normalized libraries.
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