Project description:Plant architecture is a critical trait in fruit crops that can significantly influence yield, pruning, planting density and harvesting. Most of the existing varieties of olive are traditional and their architecture is poorly suited for modern growing and harvesting systems. This study focuses on the identification of candidate genes involved in determining plant architecture in olive that could help in selecting phenotypes adapted to modern cultivation practices. We previously developed the first microarray for olive, as a means to discover candidate genes involved in relevant agronomical traits. The microarray has already been applied to identify candidates genes involved in regulating juvenile to adult transition in the shoot apex of seedlings. In the present study, made in the framework of an olive breeding program, varieties displaying differences in architecture and pooled seedlings grouped by their architecture-related phenotypes, were analysed using microarray analysis of meristematic tissue. We identify 2,258 differentially expressed genes potentially involved in determining plant architecture. Varieties with opposite architecture phenotypes and individuals from segregating progenies displaying extreme architecture features, constitute our key to linking phenotype to expression. We analyze some of the genes with potentially interesting functional annotation using quantitative RT-PCR assays, in the reference varieties and individual seedlings. Arabidopsis mutants in putative orthologs of some of the candidate genes show altered architecture, indicating functional conservation between the two species and supporting both, the biological relevance of the results, and the potential of the identified genes as markers for assisted breeding for olive varieties suited for high density orchards. Active or dormant meristems to be used for expression analysis were collected from individual olive trees from four varieties Picual, Arbequina, Arbosana and Chiquitita and from seedlings of a Picual x Arbequina progeny, all of the showing variability for growth habit. Plant material was provided by the olive breeding program of Cordoba. Harvesting was carried out between 8:00 to 11:00 a.m., at the end of Spring. Samples were immediately frozen in liquid nitrogen, and maintained afterwards at -80 ºC. Samples of the Picual x Arbequina seedlings used to generate pools were harvested individually and 0.2 g of tissue per individual mixed and processed together to obtain RNA to be used for microarray analysis.
Project description:Plant architecture is a critical trait in fruit crops that can significantly influence yield, pruning, planting density and harvesting. Most of the existing varieties of olive are traditional and their architecture is poorly suited for modern growing and harvesting systems. This study focuses on the identification of candidate genes involved in determining plant architecture in olive that could help in selecting phenotypes adapted to modern cultivation practices. We previously developed the first microarray for olive, as a means to discover candidate genes involved in relevant agronomical traits. The microarray has already been applied to identify candidates genes involved in regulating juvenile to adult transition in the shoot apex of seedlings. In the present study, made in the framework of an olive breeding program, varieties displaying differences in architecture and pooled seedlings grouped by their architecture-related phenotypes, were analysed using microarray analysis of meristematic tissue. We identify 2,258 differentially expressed genes potentially involved in determining plant architecture. Varieties with opposite architecture phenotypes and individuals from segregating progenies displaying extreme architecture features, constitute our key to linking phenotype to expression. We analyze some of the genes with potentially interesting functional annotation using quantitative RT-PCR assays, in the reference varieties and individual seedlings. Arabidopsis mutants in putative orthologs of some of the candidate genes show altered architecture, indicating functional conservation between the two species and supporting both, the biological relevance of the results, and the potential of the identified genes as markers for assisted breeding for olive varieties suited for high density orchards.
Project description:The transcriptional response to the olive fruit fly (Bactrocera oleae) reveals extended differences between tolerant and susceptible olive (Olea europaea L.) varieties
Project description:A comparative transcriptomics approach was used as a tool to unravel gene regulatory networks underlying salinity response in olive trees by simulating as much as possible olive growing conditions in the field. Specifically, we investigated the genotype-dependent differences in the transcriptome response of two olive cultivars, a salt tolerant and a salt sensitive. A 135 day long comparative salinity experiment was conducted using one year old trees exposed to NaCl stress for 90 days followed by 45 days of post-stress period. Total RNA was extracted from the root samples after 15, 45 and 90 days of NaCl-treated and un-treated olive trees as well as after 15 and 45 days of post-treatment period and used for microarray hybridizations using a loop design. Hierarchical clustering of differentially expressed transcripts revealed two major, distinct clusters for each cultivar. Despite the limited number of probe set, transcriptional regulatory networks were constructed for the salt-tolerant and salt-sensitive cultivar. The comparison of the salt responsive transcriptional regulatory networks in olive with those reported for Arabidopsis suggests that a tree species might respond in a similar to Arabidopsis way at the transcriptome level under salinity stress.
Project description:A transcriptomics approach was used as a tool to unravel gene regulatory network underlying salinity response in a salt-tolerant olive cultivar (cv. Kalamon) by simulating as much as possible olive growing conditions in the field. A 135 day long salinity experiment was conducted using one year old trees exposed to NaCl stress for 90 days followed by 45 days of post-stress period. Total RNA was extracted from the root samples after 15, 45 and 90 days of NaCl-treated and un-treated olive trees as well as after 15 and 45 days of post-treatment period and used for microarray hybridizations using a loop design. Hierarchical clustering of differentially expressed transcripts revealed two major, distinct clusters. Despite the limited number of probe set, a transcriptional regulatory networks was constructed for the salt-tolerant cultivar.
Project description:We aimed to identify miRNA regulated by alternate bearing in O. europaea. For this purpose, six olive (Olea europaea L. )(Ayvalık variety) small RNA libraries were constructed from fruits (ripe and unripe) and leaves ("on-year" and "off-year" mature -leaven in November and juvenile - leaven in July plants) and sequenced by high-throughput Illumina sequencing. Bioinformatics analyses of 93,526,915 reads identified 135 conserved miRNA, belonging to 22 miRNA families in olive tree. In addition, 38 novel miRNA were discovered in the datasets. Expression of olive tree miRNA varied greatly among the six libraries, indicating contribution of diverse miRNA in balancing between reproductive and vegetative phases. The differential expression of miRNA was evaluated on the basis of the developmental phase of the samples.