Changes in polysomes and mRNA in ageing soybean (Glycing max L.) cotyledons

Area of Science:

• Plant molecular biology
• Biochemistry of aging
• Soybean (Glycine max) physiology

Background:

• Aging in plant tissues involves complex molecular changes.
• Ribosome and messenger RNA (mRNA) dynamics are crucial for protein synthesis and cellular function.
• Understanding these dynamics in soybean cotyledons can provide insights into plant senescence.

Purpose of the Study:

• To investigate the changes in polysome profiles and mRNA activity during soybean cotyledon aging.
• To characterize the distribution of ribosomes and the presence of polyadenylated mRNA in relation to cotyledon age.

Main Methods:

• Extraction of polysomes and associated ribonucleic acids from soybean cotyledons of varying ages.
• Density gradient analysis to assess polysome distribution (monosomes vs. polysomes).
• Oligo (dT) cellulose chromatography and hybridization with 3H-polyuridylic acid to detect polyadenylated mRNA.

Main Results:

• Older soybean cotyledons showed a higher proportion of monosomes and light polysomes compared to younger cotyledons, which had more heavy polysomes.
• Polysomal and mRNA activities exhibited increased levels in 3- to 5-day-old and again in 10-day-old cotyledons.
• Polyadenylated mRNA was detected, confirming its presence in the analyzed soybean cotyledon tissues.

Conclusions:

• Soybean cotyledon aging is associated with a shift in ribosome distribution towards less active forms (monosomes).
• mRNA activity is not uniformly declining but shows specific peaks during the aging process.
• The presence of polyadenylated mRNA suggests its role in regulating gene expression during soybean cotyledon development and senescence.