Polysomes from winter rye seedlings grown at low temperature : I. Size class distribution, composition, and stability

Area of Science:

• Plant Physiology
• Molecular Biology
• Biochemistry

Background:

• Plant adaptation to temperature stress is crucial for survival and crop yield.
• Cytoplasmic polysomes are key to protein synthesis and cellular function.
• Understanding polysome response to cold is vital for plant science.

Purpose of the Study:

• To investigate the impact of low-temperature growth on rye seedling cytoplasmic polysomes.
• To analyze changes in polysome size distribution, stability, and composition.
• To compare polysome behavior in free and membrane-bound fractions.

Main Methods:

• Cultivation of rye seedlings (Secale cereale) at 5°C and 20°C.
• Quantification of cytoplasmic polysomes relative to DNA content.
• Analysis of polysome size class distribution and melting point.
• Electrophoretic examination of ribosomal RNA and proteins.

Main Results:

• Seedlings grown at 5°C had 2.7 times more cytoplasmic polysomes than those at 20°C.
• Low-temperature growth skewed polysome distribution towards larger sizes, especially in free polysomes.
• The melting point of ribosomes decreased by 3.7°C in cold-grown seedlings.
• No significant differences were found in rRNA or core-ribosomal proteins, but peripheral proteins showed variations.

Conclusions:

• Low temperature significantly modifies polysome quantity, polymerization, and melting point in rye seedlings.
• Changes in peripheral ribosomal proteins may play a role in cold adaptation.
• This study provides novel insights into plant polysome metabolism under thermal stress.