Thioredoxin and germinating barley: targets and protein redox changes

Area of Science:

• Plant Biology
• Biochemistry
• Molecular Biology

Background:

• Thioredoxin h is a key protein in redox regulation.
• Disulfide bond reduction is essential for seed germination and development.
• Barley (Hordeum vulgare L.) storage proteins are a major component of the endosperm.

Purpose of the Study:

• To investigate the roles of thioredoxin h and disulfide changes in barley germination and seedling development.
• To compare redox dynamics in barley embryo and endosperm with other cereals.
• To identify specific thioredoxin targets in the barley embryo.

Main Methods:

• Two-dimensional gel electrophoresis was used to analyze protein disulfide reduction.
• Thioredoxin h abundance was quantified during germination.
• Proteins targeted by thioredoxin were identified using H(2)O(2) oxidation.

Main Results:

• Disulfide proteins in barley embryo and endosperm reduced after imbibition, peaking earlier in the embryo.
• Barley endosperm storage proteins showed less pronounced reduction compared to other cereals and were highly reduced in dry seeds.
• Thioredoxin h decreased in the endosperm but increased in the embryo during germination.
• Specific thioredoxin targets in the barley embryo were identified, including barley embryo globulin 1 and peroxiredoxin.

Conclusions:

• Thioredoxin-linked redox changes are vital for germinating barley embryos.
• These redox processes are involved in dormancy, reactive oxygen species protection, translation, and storage protein mobilization.
• Findings extend the understanding of thioredoxin's importance beyond endosperm to the developing embryo.