Analysis of response mechanism in soybean under low oxygen and flooding stresses using gel-base proteomics technique.

A proteomics approach was used to analyze the response mechanism in soybean seedlings under low oxygen and flooding stresses. Three-day-old soybean seedlings were subjected to low oxygen and flooding stresses. Growth of root was suppressed in both stresses with more extent of suppression in flooded seedlings at 3 and 6 days following the treatments. Proteins were extracted from roots and separated by two-dimensional polyacrylamide gel electrophoresis. Of total 1,233 protein spots, 27 protein spots were commonly changed under low oxygen and flooding stresses; while the differential change in 4 and 18 protein spots was specific to low oxygen and flooding stresses, respectively. Proteins related to metabolism and energy were increased; while protein destination/storage related proteins were decreased commonly under low oxygen and flooding stresses. Protein specie, TCP domain class transcription factor was decreased specifically under low oxygen stress; while decrease of nine proteins related to metabolism, protein destination/storage and disease/defense was specific in flooded seedlings. The decrease in majority of the proteins related to protein destination/storage specifically in flooded seedlings implies the misfolding of proteins resulting in flooded injuries in an independent way of oxygen deprivation. These results suggest that decrease in proteins related to protein destination/storage and disease/defense causes more growth suppression in soybean seedlings under flooding stress compared to low oxygen stress.