Strigolactone-Regulated Proteins Revealed By iTRAQ-Based Quantitative Proteomics

Strigolactones are a new class of plant hormones. In addition to acting as a key inhibitor of shoot branching, strigolactones stimulate seed germination of root parasitic plants and promote hyphal branching and root colonization of symbiotic arbuscular mycorrhizal fungi. At the transcription level, strigolactones regulate the expression of many genes. However, nothing is known about the proteome regulated by this new class of plant hormones. Here, a quantitative proteomics approach using an isobaric chemical labeling reagent, iTRAQ, to identify the proteome regulated by strigolactones in the model plant Arabidopsis is presented. It was found that in addition to regulating the abundance of proteins implicated in strigolactone pathways, strigolactones also regulate the expression of a number of proteins that have not been previously assigned to strigolactone pathways. Furthermore, a drastic difference between strigolactone-regulated transcriptome and strigolactone-regulated proteome was observed. These findings provide a new tool to investigate the molecular mechanism of action of strigolactones.