iTRAQ-based quantitative proteomics of developing and ripening muscadine grape berry

Area of Science:

• Plant Science
• Biochemistry
• Molecular Biology

Background:

• Grapes are globally significant fruit crops undergoing complex ripening changes.
• Muscadine grapes (Vitis rotundifolia) are vital in the southern US for fresh consumption and wine production.
• While muscadine metabolite changes are known, molecular alterations during ripening remain less understood.

Purpose of the Study:

• To investigate the proteomic changes during berry development and ripening in muscadine grape (Vitis rotundifolia) cv. Noble.
• To identify proteins differentially expressed during muscadine grape ripening.

Main Methods:

• Utilized isobaric tags for relative and absolute quantification (iTRAQ) coupled with tandem mass spectrometry (MS/MS) for proteomic analysis.
• Analyzed protein expression across four distinct time points during muscadine berry ripening.
• Employed quantitative real-time PCR (qRT-PCR) to validate protein expression levels for selected proteins.

Main Results:

• Detected a total of 674 proteins, with 76 identified as differentially expressed during muscadine berry ripening.
• Observed upregulation of proteins associated with abiotic/biotic stress responses and sucrose/hexose metabolism.
• Identified vicilin-like antimicrobial peptides, suggesting enhanced disease tolerance mechanisms in ripening muscadine berries.

Conclusions:

• The study provides novel insights into the muscadine grape berry proteome during ripening.
• Identified key proteins involved in stress tolerance and metabolic pathways crucial for grape development.
• Contributes to a deeper understanding of the molecular basis of grape ripening and berry protection.