Flooding injury is a major problem in soybean cultivation. A proteomics approach was used to clarify the occurrence of changes in protein expression level and phosphorylation in soybeans under flooding stress. Two-day-old seedlings were flooded for 1 day, proteins were extracted from root tips of the seedlings and digested with trypsin, and their expression levels and phosphorylation states were compared to those of untreated controls using mass spectrometry-based proteomics techniques. Phosphoproteins were enriched using a phosphoprotein purification column prior to digestion and mass spectrometry. The expression of proteins involved in energy production increased as a result of flooding, while expression of proteins involved in protein folding and cell structure maintenance decreased. Flooding induced changes of phosphorylation status of proteins involved in energy generation, protein synthesis and cell structure maintenance. The response to flooding stress may be regulated by both modulation of protein expression and phosphorylation state. Energy-demanding and production-related metabolic pathways may be particularly subject to regulation by changes in protein phosphorylation during flooding.

Plants grow and reproduce in the radioactive Chernobyl area, however there has been no comprehensive characterization of these activities. Herein we report that life in this radioactive environment has led to alteration of the developing soybean seed proteome in a specific way that resulted in the production of fertile seeds with low levels of oil and β-conglycinin seed storage proteins. Soybean seeds were harvested at four, five, and six weeks after flowering, and at maturity from plants grown in either non-radioactive or radioactive plots in the Chernobyl area. The abundance of 211 proteins was determined. The results confirmed previous data indicating that alterations in the proteome include adaptation to heavy metal stress and mobilization of seed storage proteins. The results also suggest that there have been adjustments to carbon metabolism in the cytoplasm and plastids, increased activity of the tricarboxylic acid cycle, and decreased condensation of malonyl-acyl carrier protein during fatty acid biosynthesis.

The accident at the Chernobyl Nuclear Power Plant (CNPP) on April 26, 1986 is the most serious nuclear disaster in human history. Surprisingly, while the area proximal to the CNPP remains substantially contaminated with long-lived radioisotopes including (90)Sr and (137)Cs, the local ecosystem has been able to adapt. To evaluate plant adaptation, seeds of a local flax (Linum usitatissimum) variety Kyivskyi were sown in radio-contaminated and control fields of the Chernobyl region. A total protein fraction was isolated from mature seeds, and analyzed using 2-dimensional electrophoresis combined with tandem-mass spectrometry. Interestingly, growth of the plants in the radio-contaminated environment had little effect on proteome and only 35 protein spots differed in abundance (p-value of ≤0.05) out of 720 protein spots that were quantified for seeds harvested from both radio-contaminated and control fields. Of the 35 differentially abundant spots, 28 proteins were identified using state-of-the-art MS(E) method. Based on the observed changes, the proteome of seeds from plants grown in radio-contaminated soil display minor adjustments to multiple signaling pathways.