The study was performed to explore the molecular changes in the vegetative stage (3-and 5-leaf) of sorghum under waterlogging stress. A total of 74 differentially expressed protein spots were analyzed using LTQ-FT-ICR MS. Among them, 12 proteins were up-regulated and 3 proteins were down-regulated. Mass spectrometry (MS) results showed that about 50% of the proteins involved in various metabolic processes. The level of protein expression of malate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase related to carbohydrate metabolic process increased in both 3 and 5-leaf stage under waterlogging stress. These proteins are known to function as antistress agents against waterlogging stress. The expression of oxygen-evolving enhancer protein 1 protein related to photosynthesis was slightly increased in the treated group than in the control group, however the expression level was increased in the 5-leaf stage compared to the 3-leaf stage. Probable phospholipid hydroperoxide glutathione peroxidase protein and superoxide dismutase protein related to response to oxidative stress showed the highest expression level in 5-leaf stage treatment. This suggests that the production of reactive oxygen species by the waterlogging stress was the most abundant in the 5-leaf treatment group, and the expression of the antioxidant defense protein was increased.

The roots of Platycodon grandiflorum are known as traditional medicine, has been extensively used since ancient times as a therapeutic to treat cold, cough and asthma in Korean traditional medications. This study was conducted in order to profile proteins from the hormone induced diploid and tetraploid roots using high throughput proteome approach. Two dimensional gels stained with CBB, a total of 64 differential expressed proteins were identified from the diploid root using image analysis by Progenesis SameSpot software. Out of total differential expressed spots, 20 differential expressed protein spots (≥ 2-fold) were analyzed using MALDI-TOF-TOF mass spectrometry whereas a total of 13 protein spots were up regulated and 7 protein spots were down-regulated. However, in the case of tetraploid root, a total of 78 differential expressed proteins were identified from tetraploid root of which a total of 28 differential expressed protein spots (≥ 2-fold) were analyzed by mass spectrometry whereas a total of 16 protein spots were up regulated and a total of 12 protein spots were down-regulated. However, proteins identified using iProClass databases revealed that the identified proteins from the explants were mainly associated with the nucleic acid binding, oxidoreductase activity, transporter activity and isomers activity. The exclusive protein profile may provide insight clues for better understanding the characteristics of proteins and metabolic activity in various explants of the economically important medicinal plant Platycodon grandiflorum.