Cucumber transcriptome tells story of early fruit development from fruit set through exponential growth

ABSTRACT: Early stages of fruit growth from initial set through exponential growth are critical determinants of size and yield, however, there has been little detailed analysis of this phase of development. In this study we combined morphological analysis with 454 pyrosequencing to study gene expression changes occurring in young cucumber fruit at five ages from anthesis through the end of exponential growth. The resulting 1.13 million ESTs were assembled into 27,859 contigs with a mean length of 834 base pairs and a mean of 67 reads per contig. Principal component analysis separated the fruit ages into three groups corresponding with cell division/pre-exponential growth (0 and 4 days post pollination (dpp)), peak exponential expansion (8dpp), and late/post-exponential expansion stages of growth (12 and 16 dpp). Transcripts predominantly expressed at 0 and 4 dpp included homologs of histones, cyclins, and plastid and photosynthesis related genes. The group of genes with peak expression at 8dpp included cytoskeleton, cell wall, and lipid metabolism related genes and phloem specific proteins. This group also was dominated by genes with unknown function or without Arabidopsis homologs, suggesting unique factors contributing to the rapid growth phase in cucurbits. A second shift in gene expression was observed at 12-16dpp, which was characterized by abiotic and biotic stress related genes and significant enrichment for stress related- and developmental- transcription factor gene homologs. Collectively, the gene expression information coupled with morphological analyses tells a progressive story of cell division, development of photosynthetic capacity, cell expansion and fruit growth, phloem activity, protection of the fruit surface, and finally transition away from fruit growth toward defense and maturation.

ORGANISM(S): Cucumis sativus var. sativus

PROVIDER: GSE39310 | GEO | 2012/07/13

REPOSITORIES: GEO