Comparative studies on differently expressed proteomes of developing and abortive ovary in hazelnut

ObjectiveThe aim of this study is to screen candidate proteins which may be involved in the regulation of abortive ovary formation in hazelnut and provide scientific base for its genetic improvement.

MethodHybrid hazelnut (Corylus heterophylla × C. avellana) cultivar 'Dawei' was used as study materials, and iTRAQ (Isobaric tags for relative and absolute quantification) technology was performed using protein extracted from abortive ovaries and developing ovaries. COG (Cluster of orthologous groups of proteins) functional classification was carried out using all the identified proteins, and their potential biological functions were predicted. Subsequently, significantly differently expressed proteins (DEPs) were identified according to protein quantification results, and GO (Gene ontology) and KEGG (Kyoto encyclopedia of genes and genomes) enrichment analysis of DEPs were carried out to explore their general molecular functions and important KEGG pathways. Finally, potential important proteins involved in abortive ovary formation were chosen mainly from significantly enriched KEGG pathways.

ResultProtein identification generated 317068 total spectra, 14267 unique peptides and 3538 proteins. Functional class of R, O, J, G and C in COG analysis accounted for 19.36%, 9.97%, 7.80%, 7.67% and 6.76% of total proteins with COG annotations. In total, 249 DEPs were identified in the paired comparison of developing and abortive ovary, including 180 and 69 up- and down-regulated DEPs. Based on GO and KEGG enrichment analysis results, these DEPs mainly executed binding and catalysis molecular functions, and 11 significant enriched KEGG pathways were identified, including phenylpropanoid biosynthesis (ko00940), photosynthesis (ko00195), metabolic pathways (ko01100), photosynthesis-antenna proteins (ko00196) and biosynthesis of secondary metabolites (ko01110). Thirty-seven important candidate DEPs were identified and these DEPs may contribute to abortive ovary formation in hazelnut.

ConclusionProteins related to photosynthesis, carbohydrate transport and metabolism, energy production and conversion, pollen tube growth and DNA methylation may regulate ovary abortion in hazel. Our findings provide insight into the molecular mechanisms of ovary abortion in hazelnut.