Protective proteins are differentially expressed in tomato genotypes differing for their tolerance to low-temperature...

Area of Science:

• Plant Physiology
• Molecular Biology
• Biochemistry

Background:

• Low-temperature storage of tomato fruits can induce chilling injury, characterized by undesirable texture changes and irregular ripening.
• Understanding the molecular mechanisms underlying chilling tolerance is crucial for improving postharvest quality.

Purpose of the Study:

• To identify proteins associated with chilling tolerance in tomato fruits.
• To compare protein expression profiles between two near-isogenic tomato lines with differing chilling sensitivities.

Main Methods:

• Comparative proteomic analysis using two-dimensional electrophoresis and mass spectrometry.
• Assessment of fruit quality parameters including color, ethylene emission, and texture.
• Controlled storage trials at different temperatures (4°C and 20°C) over several days.

Main Results:

• Identified 85 proteins with expression levels varying by genotype or storage temperature.
• Observed decreased expression of maturation-related proteins (e.g., acidic invertase) under cold storage.
• Found up-regulation of proteins associated with freezing tolerance and identified specific small heat shock protein isoforms and endoplasmic reticulum stress-related proteins.

Conclusions:

• The study identified key proteins, including specific small heat shock protein isoforms and those involved in endoplasmic reticulum stress response, that contribute to differential chilling resistance in tomato lines.
• Findings suggest that post-translational regulation of enzymes like polygalacturonase may play a role in chilling response.
• The most firm genotype at harvest was unexpectedly more sensitive to cold storage, highlighting complex interactions in chilling tolerance.