Thioredoxin targets of developing wheat seeds identified by complementary proteomic approaches

Area of Science:

• Plant Biochemistry
• Proteomics
• Molecular Biology

Background:

• Thioredoxins are crucial redox-active proteins involved in various cellular processes.
• Understanding thioredoxin function in wheat endosperm is vital for grain development and quality.

Purpose of the Study:

• To investigate the role of thioredoxin in wheat starchy endosperm.
• To identify novel thioredoxin targets in developing and mature wheat endosperm and flour.

Main Methods:

• Utilized two complementary proteomic approaches: 1) NADP/thioredoxin system reduction followed by monobromobimane labeling of sulfhydryl groups, and 2) affinity chromatography using a mutant thioredoxin.
• Isolated thioredoxin targets from KCl-soluble extracts of endosperm and flour, separated by 2D gel electrophoresis (2-DE).

Main Results:

• Identified a total of 68 potential thioredoxin targets, with 40 novel proteins not previously described in seeds.
• Proteins identified contained conserved cysteines, suggesting redox-dependent interactions.
• Distinct sets of thioredoxin targets were observed in young versus mature endosperm, reflecting developmental roles.
• Flour proteome analysis revealed 36 thioredoxin targets, largely overlapping with those in developing endosperm.

Conclusions:

• This research expands the known interactome of thioredoxin in wheat endosperm.
• The findings highlight the diverse roles of thioredoxin in wheat grain development and post-harvest processing.
• Identified novel targets provide a basis for future functional studies on thioredoxin in cereal seeds.