Shigenobu Kaneko

Peptide mapping and assessment of cryoprotective activity of 26/27-kDa dehydrin from soybean seeds.

To characterize the molecular weight diversity of seed dehydrin among soybean cultivars, 26/27-kDa soybean dehydrins were purified and compared in peptide mapping patterns, partial amino acid sequences, and cryoprotective activity on enzyme. In reverse phase chromatograms of their trypsin digests, we detected several distinctive peaks, one of which was attributed to a part of the internal glycine-rich region. Partial amino acid sequences of peptide fragments from trypsin and S. aureus V8 protease cleavage were found to be identical to the Mat9 translation. The CP50 of purified 26/27-kDa dehydrins were estimated to be 0.30 and 0.11 μM, respectively.

Cadmium Concentration in Grains of Japanese Wheat Cultivars : Genotypic Difference and Relationship with Agronomic Characteristics

The contamination of cadmium (Cd) into the food chain can be harmful because Cd causes chronic health problems. To evaluate the breeding potential reducing the Cd concentration in wheat grain, we compared Cd concentrations in 237 wheat genotypes including Japanese landraces, Japanese cultivars and introduced alien cultivars for breeding using grain samples collected from upland fields in 2004−5 and 2005−6 growing seasons. The Cd concentration in wheat grain significantly varied with the growing seasons and with the experimental fields. Cultivars bred in northern Japan, including the recent Japanese leading cultivar ‘Hokushin’, tended to have a low Cd concentration in grain compared with that bred in central and southern Japan. Simple correlation analysis between Cd concentration in grain and agronomic characteristics revealed that the Cd concentration in grain showed significant negative correlations with stem number, culm length and spikelet number per spike, and showed significant positive correlation with SPAD value (chlorophyll content) of flag leaf. Stepwise multipleregression analysis showed that the genotypic variation of Cd concentration in grain was associated with the culm length and spiklet number per spike. This study clarified the geographical pattern of genotypes with different Cd concentrations in grain in Japanese wheat cultivars. Cultivars originating from northern Japan may be useful genetic resources to develop cultivars with a low Cd concentration in grain to be grown in the areas where Cd accumulation in wheat grain is a problem.