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The deployment of marker-assisted breeding strategies in blackcurrant has started with the use of a PCR-based marker for gall mite resistance. This is now a routine part of the selection process within the breeding programmes at the James Hutton Institute, and further work is in progress to develop similar approaches for other more complex traits. Whilst the need for accurate field-and glasshouse-based phenotyping has never been more vital, the integration of enhanced phenotyping with the development of significant genomics resources offers an important opportunity for the improvement of breeding efficiency in blackcurrant.

Blackcurrant fruit collected at six stages of development were assessed for changes in gene expression using custom whole transcriptome microarrays and for variation in metabolite content using a combination of liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. Principal components analysis demonstrated that fruit development could be clearly defined according to their transcript or metabolite profiles. During early developmental stages, metabolite profiles were dominated by amino acids and tannins, whilst transcript profiles were enriched in functions associated with cell division, anatomical structure morphogenesis and cell wall metabolism. During mid fruit development, fatty acids accumulated and transcript profiles were consistent with seed and embryo development. At the later stages, sugars and anthocyanins accumulated consistent with transcript profiles that were associated with secondary metabolism. Transcript data also indicated active signaling during later stages of fruit development. A targeted analysis of signaling networks revealed a dynamic activation and repression of almost 60 different transcripts encoding transcription factors across the course of fruit development, many of which have been demonstrated as pivotal to controlling such processes in other species. Transcripts associated with cytokinin and gibberellin were highly abundant at early fruit development, whilst those associated with ABA and ethylene tended to be more abundant at later stages. The data presented here provides an insight into fruit development in blackcurrant and provides a foundation for further work in the elucidation of the genetic basis of fruit quality.

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What is already known on this subject? • Drought is a major limitation for crop productivity worldwide and in future periods of water stress are more likely to occur. Molecular responses to drought stress are very complex, but our understanding has rapidly progressed with the identification of thousands of genes involved in acclimatization and adaptation. What are the new findings? • Genome expression analyses from blackcurrant 'Ben Gairn' after five days of drought stress. Volcano filtering identified 2,115 differentially expressed microarray probes; 429 were up-regulated, with 263 showing homology to unique Arabidopsis thaliana (At) accessions, and 1,686 were down-regulated, with 675 unique At numbers. What is the expected impact on horticulture? • Putative candidate genes involved in drought stress tolerance of blackcurrant were identified, but require further, more detailed, studies to confirm their role. The results provide relevant information for focusing future studies with the aim to develop drought tolerant cultivars for sustainable production.