Hiroshi Yakushiji

Comparison of UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT) gene sequences between white grapes (Vitis vinifera) and their sports with red skin.

The expression of the UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT) gene has been shown to be critical for anthocyanin biosynthesis in the grape berry. Using white cultivars and bud sports with red skin, we examined the expression of seven anthocyanin biosynthetic genes including the UFGT gene and compared the coding/promoter sequences of the UFGT gene. Northern blot analysis showed that the seven anthocyanin biosynthetic genes were expressed coordinately at higher levels in the red-skin sports than in the white-skin progenitors of the sports. It was especially notable that UFGT gene expression was detected only in the red-skin sports and Kyoho. However, there were no differences in either coding or promoter sequences between Italia (Vitis vinifera) and its red-skin sport Ruby Okuyama, or between Muscat of Alexandria (V. vinifera) and the red-skin sport Flame Muscat. From these findings, the phenotypic change from white to red in the sports is thought to be the result of a mutation in a regulatory gene controlling the expression of UFGT.

A skin color mutation of grapevine, from black-skinned pinot noir to white-skinned pinot blanc, is caused by deletion of the functional VvmybA1 allele

A white-wine grape, Pinot Blanc, is thought to be a white-skinned mutant of a red-wine grape, Pinot Noir. Pinot Noir was heterozygous for VvmybA1. One allele was the non-functional VvmybA1a, and the other was the functional VvmybA1c. In Pinot Blanc, however, only VvmybA1a was observed, and the amount of VvmybA1 DNA in Pinot Blanc was half that in Pinot Noir. These findings suggest that deletion of VvmybA1c from Pinot Noir resulted in Pinot Blanc.

Growth dependence of ovaries of facultatively parthenocarpic eggplant in vitro on indole-3-acetic acid content

This work was undertaken to investigate the growth of tissue-cultured ovaries of facultatively parthenocarpic eggplant in vitro in relation to their indole-3-acetic acid (IAA) content. Ovaries isolated from facultatively parthenocarpic eggplant (Solanum melongena L. cv Talina) and nonparthenocarpic eggplant (S. melongena L. cv Senryo-nigo) were grown under tissue culture conditions. The ovaries of facultatively parthenocarpic eggplant grew for 40 days on hormone-free medium when sucrose concentration was 50‐70 g l ˇ1 . The growth of ovaries of non-parthenocarpic eggplant ceased after 10 days. The ovaries of facultatively parthenocarpic eggplant on the medium containing 2,3,5-triiodobenzoic acid (TIBA) did not develop at all. The levels of IAA in the ovaries of both facultatively parthenocarpic and non-parthenocarpic plants were identical at excision, but were higher in ovaries of facultatively parthenocarpic than in those of non-parthenocarpic eggplant and ovaries of facultatively parthenocarpic eggplant grown on the medium containing TIBA at 20 and 40 days after culture initiation. Our findings indicated that the growth of the ovaries of facultatively parthenocarpic eggplant is supported by the availability of endogenous IAA. # 1999 Elsevier Science B.V. All rights reserved. Scientia Horticulturae 79 (1999) 143‐150

Evaluation of Grape Flesh Texture by Acoustic Vibration Method

Abstract To clarify the characteristics of grape flesh texture, acoustic vibrations generated by inserting a probe in grape flesh were measured. Texture index (TI) based on energy density, which was calculated from vibration signals, could be used to classify 9 grape cultivars into 3 groups with their flesh textures evaluated as crisp, noncrisp, and intermediate, while breaking force measured by a conventional intrusive method did not. TI of 0–50-Hz band correlated with the breaking force, suggesting that TI of 0–50-Hz corresponds to flesh firmness, and TI of higher frequency characterizes crispness of grape flesh.