Microarray analysis of gene expression patterns during fruit development in European pear (Pyrus communis)

We used microarray analysis to search for novel ripening- or development-related genes in the fruits of European pear (. Pyrus communis). Genes were classified into 20 clusters according to expression pattern. Several clusters showed stage-specific expression. Genes expressed until full bloom were dominated by photosynthesis-related genes. Genes expressed at 30 days after full bloom were dominated by those for the biosynthesis of flavonoids, lignin, and fatty acids. Since RNA from fruit skin was included in 30 days after full bloom, high expression of these genes might be due to fruit skin. Gene expressed during ripening were dominated by those for ethylene biosynthesis and cell wall modification. Among ripening-specific genes, one cupin family protein gene and two unannotated genes, which are not induced in Japanese pear (. Pyrus pyrifolia), were induced in P. communis. These genes are likely to be involved in the ripening characteristics specific to P. communis. Our fruit flesh transcriptome data, spanning fruit development from before full bloom to the full ripe stage, will be helpful in studying fruit development and surveying genes important in flesh development in P. communis.