Soo Jeong Kwon

Morpho-Physiological and Proteome Level Responses to Cadmium Stress in Sorghum

Cadmium (Cd) stress may cause serious morphological and physiological abnormalities in addition to altering the proteome in plants. The present study was performed to explore Cd-induced morpho-physiological alterations and their potential associated mechanisms in Sorghum bicolor leaves at the protein level. Ten-day-old sorghum seedlings were exposed to different concentrations (0, 100, and 150 μM) of CdCl2, and different morpho-physiological responses were recorded. The effects of Cd exposure on protein expression patterns in S. bicolor were investigated using two-dimensional gel electrophoresis (2-DE) in samples derived from the leaves of both control and Cd-treated seedlings. The observed morphological changes revealed that the plants treated with Cd displayed dramatically altered shoot lengths, fresh weights and relative water content. In addition, the concentration of Cd was markedly increased by treatment with Cd, and the amount of Cd taken up by the shoots was significantly and directly correlated with the applied concentration of Cd. Using the 2-DE method, a total of 33 differentially expressed protein spots were analyzed using MALDI-TOF/TOF MS. Of these, treatment with Cd resulted in significant increases in 15 proteins and decreases in 18 proteins. Major changes were absorbed in the levels of proteins known to be involved in carbohydrate metabolism, transcriptional regulation, translation and stress responses. Proteomic results revealed that Cd stress had an inhibitory effect on carbon fixation, ATP production and the regulation of protein synthesis. Our study provides insights into the integrated molecular mechanisms involved in responses to Cd and the effects of Cd on the growth and physiological characteristics of sorghum seedlings. We have aimed to provide a reference describing the mechanisms involved in heavy metal damage to plants.

Inheritance of Self-Compatibility in a Buckwheat Hybrid

Abstract This study was conducted to determine the inheritance of self-compatibility and homomorphic flower type when the wild species Fagopyrum homotropicum was crossed with common buckwheat (Fagopyrum esculentum). Unidirectional interspecific hybrids between cultivated F. esculentum Moench. (common buckwheat) and its wild relative F. homotropicum were produced after controlled pollination and embryo rescue culture. Cross-compatibility was found to be better when thrum-type common buckwheat was used as the female parent rather than the pin-type. The resulting F1 plants were partially fertile, late maturing, and intermediate between the parents in flower shape and plant height. They segregated into heterostylic (thrum only) and homostylic types in equal number, indicating that homostyly is controlled by a single dominant gene. The thrum-type F1 hybrids were backcrossed to common buckwheat and the progenies were raised utilizing embryo rescue culture. The homostylic F1 hybrids were advanced to the F2 and F3 generations through self-fertilization and utilized, together with the BC1F1, for the analysis of the stylar genes. The results obtained indicate that the genes coding for heterostyly and homostyly are controlled by the multiple allelic gene S. It appears that the pin/thrum complex in F. esculentum is governed by a single genetic locus S with two alleles, S and s, that control the reaction in Ss (thrum-type) as well as the ss (pin-type) plants, respectively. The homomorphic flower type of F. homotropicum is governed by the allele Sh. These genes can be characterized by a relationship of dominance, i.e., S>Sh>s. The introgression of F. homotropicum genes into common buckwheat was verified by means of electrophoretic analysis of seed proteins.

Distribution of Amino Acids in Buckwheat

Abstract The amino acids found to be abundant in common buckwheat (CB) sprouts was Val (40%), followed by Tyr (28%), whereas Val accounted for 62% in Tartary buckwheat (TB). The buckwheat stem and root commonly contained Gln (40%–42% in stem; 30%–37% in root). Thus, soluble amino nitrogen source is used for Gln in buckwheat. The main difference of amino acid distribution in 3 tissues between CB and TB was Tyr in sprouts. A low level of Tyrin TB presumably resulted from the conversion to other phenolic metabolites. The content of essential free amino acids in TB sprout was 53% higher than that in CB. Thus, the TB sprouts are beneficial to human nutrition.

Evaluation of Physiological Functionalities and Anti-inflammatory Activity on in vitro Cultured Adventitious Root of Platycodon grandiflorum

This study was executed to evaluate the phenolic content, DPPH, ABTS radical scavenging rate, nitrite scavenging rate, and anti-inflammatory activity from in vitro cultured adventitious root extract of different Platycodon grandiflorum(PG) variety. Total polyphenol and flavonoid content showed the highest amount in adventitious root extract of tetraploid PG, and followed by green petal, double petal and diploid PG extract. The DPPH radical scavenging activity showed that the increase was proportional to the concentration, especially, the scavenging activity at a concentration of 10 mg mL-1 was higher than 80%. The ABTS radical scavenging activity was not significantly different among the PG varieties at the concentration of 5 mg mL-1 or more, and generally showed high scavenging activity. The nitrite scavenging activity was affected by pH, at pH of 1.2, the scavenging effect of all of the extracts tested observed higher than that of the other two pH ranges. The cytotoxicity of PG extract at various concentrations, the survival rate of RAW 264.7 cell was more than 90% at a concentration of 200 μg mL-1 or less, and it was confirmed that the macrophage cell showed little toxicity. After PG extract pretreatment at 50, 100, and 200 μg mL-1, LPS-treated experimental group significantly inhibited NO production in a dose-dependent manner. The dose-response trends followed quadratic regressions in all PG varieties. The PG extracts showed a considerable range of influence on cytokine secretion. The effect of adventitious root extracts of PG against inflammatory mediators TNF-α, IL-6 and IL-1β production showed the most significant anti-inflammatory activity.

In vivo Acclimatization Responses of Platycodon grandiflorum For. Duplex to Different Soil Types and Environmental Factors

This study aimed to evaluate the effects of soil types and environmental factors for optimum conditions of seedlings growth of the Platycodon grandiflorum for establishing the in vivo acclimatization system of regenerated plants derived from the in vitro culture. P. grandflorum seedlings were transferred to the in vivo condition and acclimatized under different soil types, light intensities, and various temperatures. Changes caused by environmental factors and soil types in plant growth viz. plant height, leaf width, leaf length, stem diameter, number of leaves, branches and nodes were recorded in this study. Among the nine types of soil, the best growth performances were obtained from the soil type SVP (Soil mixed with horticultural bed soil, vermiculite, and perlite @ 2:1:1). Seedlings of P. grandiflorum showed the best growth at higher levels of light intensity (60 μmol·m-2·s-1). In contrast, P. grandiflorum seedlings showed the best growth response at a moderate level of temperature (25°C). Collectively, the present study provides a better understanding of the responses of growth characteristics in P. grandiflorum seedlings exposed to various soil types, light intensities, and temperatures.