Project description:Breeding day-neutral strawberry (Fragaria x ananassa Duchesne) is pivotal to extend fruit-bearing season and increase the efficiency of production. However, genetic improvement of day-neutrality by the means of molecular marker technologies remains slow due to genome complexity of octoploid strawberry. This study employs an innovative approach by integrating the Subtracted Diversity Array (SDA) technology and Bulked Segregant Analysis (BSA) to facilitate the identification of molecular markers associated with day-neutrality in octoploid strawberry. A Fragaria Discovery Panel (FDP) containing 287 features specific to strawberry genome was constructed as a platform for rapid screening of DNA polymorphism between one short day (SD) strawberry DNA bulk and three day-neutral (DN) bulks varrying in flowering strength. Differential array hybridisation patterns between the DN and SD bulks revealed a novel molecular marker, FaP2E11, closely linked to CYTOKININ OXIDASE 1 (CKX1) gene possibly involved in promoting flowering under non-inductive condition. Interestingly, a 12 bp deletion was observed within the FaP2E11 sequence cloned from SD genotypes but not DN genotypes. As cytokinin is required to induce flowering, this result indicates that full sequence of FaP2E11 and the sequence with deletion are allelic variants linked to the low enzyme activity CKX1 and the wild type alleles, respectively.
Project description:In this RNA-seq study, we compared the transcriptome of three Fragaria vesca genotypes in response to Phytophthora cactorum. The goal of our study was to dissect the resistance mechanism of the diploid strawberry (F. vesca) that are resistant to P. cactorum. A susceptible genotype (NCGR1218) and two resistant (NCGR1603 and Bukammen) F. vesca genotypes were used for the comparative transcriptome analyses. Plants were inoculated with P. cactorum zoospores (2mL of 2 × 105 spores/mL) in the crown (rhizome) and sampled 48 hours later. The appropriate controls for each genotype were i) samples wounded and inoculated with water and sampled 48 hours after the treatment and ii) untreated samples. Four biological replicates, each consisting of four individual test plants from each genotype were used for the transcriptome study. All the samples were collected from the crown, flash-frozen in liquid nitrogen and stored at -80 °C until RNA isolation. Total RNA was isolated using the SpectrumTM Plant Total RNA Kit (Sigma-Aldrich, USA) according to the manufacturer’s instructions. For sequencing, the libraries were prepared using the TruSeqTM stranded total RNA library prep kit (Illumina, USA), indexed and pooled, and sequenced in four lanes using the Illumina HiSeq 3/4000 (2×150 bp) System by the Norwegian Sequencing Centre, Oslo, Norway. Raw reads were quality filtered, de novo assembled into transcripts and were analysed for differentially expressed genes between the inoculated and control samples.
Project description:Fragaria vesca, a diploid woodland strawberry with a small and sequenced genome, is an excellent model for studying fruit development. The strawberry fruit is unique in that the edible flesh is actually enlarged receptacle tissue. The true fruit are the numerous dry achenes dotting the receptacleM-^Rs surface. Auxin produced from the achene is essential for the receptacle fruit set, a paradigm for studying crosstalk between hormone signaling and development. To investigate the molecular mechanism underlying strawberry fruit set, next-generation sequencing was employed to profile early-stage fruit development with five fruit tissue types and five developmental stages from floral anthesis to enlarged fruits. This two-dimensional data set provides a systems-level view of molecular events with precise spatial and temporal resolution.