Choong-Hoon Park

Proteome analysis of soybean roots under waterlogging stress at an early vegetative stage

To gain better insight into how soybean roots respond to waterlogging stress, we carried out proteomic profiling combined with physiological analysis at two time points for soybean seedlings in their early vegetative stage. Seedlings at the V2 stage were subjected to 3 and 7 days of waterlogging treatments. Waterlogging stress resulted in a gradual increase of lipid peroxidation and in vivo H2O2 level in roots. Total proteins were extracted from root samples and separated by two-dimensional gel electrophoresis (2-DE). A total of 24 reproducibly resolved, differentially expressed protein spots visualized by Coomassie brilliant blue (CBB) staining were identified by matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry or electrospray ionization tandem mass spectrometry (ESI-MS/MS) analysis. Of these, 14 proteins were upregulated; 5 proteins were decreased; and 5 were newly induced in waterlogged roots. The identified proteins include well-known classical anaerobically induced proteins as well as novel waterlogging-responsive proteins that were not known previously as being waterlogging responsive. The novel proteins are involved in several processes, i.e. signal transduction, programmed cell death, RNA processing, redox homeostasis and metabolisms of energy. An increase in abundance of several typical anaerobically induced proteins, such as glycolysis and fermentation pathway enzymes, suggests that plants meet energy requirement via the fermentation pathway due to lack of oxygen. Additionally, the impact of waterlogging on the several programmed cell death- and signal transduction-related proteins suggest that they have a role to play during stress. RNA gel blot analysis for three programmed cell death-related genes also revealed a differential mRNA level but did not correlate well with the protein level. These results demonstrate that the soybean plant can cope with waterlogging through the management of carbohydrate consumption and by regulating programmed cell death. The identification of novel proteins such as a translation initiation factor, apyrase, auxin-amidohydrolase and coproporphyrinogen oxidase in response to waterlogging stress may provide new insight into the molecular basis of the waterlogging-stress response of soybean.

Effect of Plant Growth Regulators on Callus Induction and Plant Regeneration from Mature Seeds of Red Top Bentgrass (Agrostis alba L.)

In order to develop a simple and reproducible protocol for red top bentgrass (Agrostis alba L.), effect of different growth regulators was investigated for embrogenic calli induction and subsequent plant regeneration using mature seeds. MS medium containing 2 mg/L 2,4-D was optimal for embryogenic callus induction from mature seeds. The highest plant regeneration frequency (64.4%) was showed when the embryogenic callus tissues were cultured on N6 medium supplemented with 0.5 mg/L 2,4-D and 2 mg/L BA. Regenerated plantlets were grown normally when shoots transplanted to the soil. A high-frequency and efficient regeneration system from mature seeds would be helpful for molecular breeding of new variety of red top bentgrass through Agrobacterium-mediated genetic transformation.