Activity-Based Profiling of Papain-like Cysteine Proteases in Different Plant Organs During Barley Development

Area of Science:

• Plant Biology
• Biochemistry
• Proteomics

Background:

• Papain-like cysteine proteases (PLCPs) are essential enzymes regulating key plant developmental processes.
• Understanding the diversity and roles of active PLCPs in barley is crucial for agricultural applications.

Purpose of the Study:

• To comprehensively analyze the active PLCPs present in various barley organs throughout different developmental stages.
• To identify specific PLCPs and their subfamilies involved in barley growth, germination, and organ development.

Main Methods:

• Protein extraction from barley tissues (seedlings, mature plants, seeds) at various growth points.
• Anion-exchange chromatography, biotinylation with DCG-04, affinity purification, and SDS-PAGE for active PLCP isolation.
• Tandem mass spectrometry (LC-MS/MS) for the identification and quantification of identified PLCPs.

Main Results:

• Identification of up to 23 distinct active PLCPs across nine subfamilies in barley.
• HvPap-6 (L-like D subfamily) was the most abundant PLCP identified in all analyzed samples.
• Specific PLCP subfamilies (L-like B and C) were found to be crucial for seedling development, with some showing organ-specific expression patterns.

Conclusions:

• Active PLCPs play diverse and critical roles in barley development, from germination to senescence.
• The abundance and activity of specific PLCPs vary significantly across different barley organs and developmental stages.
• Certain PLCPs exhibit organ-specific expression, highlighting their specialized functions in barley physiology.