We transformed the European pear (Pyrus communis L.) 'La France' and 'Ballade' with the Citrus FLOWERING LOCUS T (CiFT) gene, which induces early flowering. Subsequent DNA blot analysis of the transformed and wild-type plants indicated that the transformed plants carried 1-4 copies of CiFT. Of the 8 transformed 'La France' and 7 transgenic 'Ballade' plant lines obtained, 7 and 5 lines respectively, flowered early when cultivated in vitro in a micropropagation medium. No correlation was found between the CiFT copy number and early flowering in vitro, however, the results of RNA gel blot analysis indicated a strong correlation between the expression of the CiFT gene and floral bud differentiation in vitro. Flowers that developed in vitro differed from wild-type flowers in terms of phenotypic traits, such as the number of pistils, petals, sepals, and stamens. To investigate the inheritance pattern of the CiFT gene, we obtained 15 seeds from the fruits of P. communis L. 'Bartlett' plants that were cross-pollinated with transgenic line No. 6, which had the second highest expression of the transgene. Of 7 seedlings that expressed the CiFT gene, 5 flowered within 10 months after they were transferred to a greenhouse. This result indicated that the CiFT gene induced early flowering in the transformed pear plants and that their progeny inherited the early flowering phenotype.

Freeze-drying (FD) is a useful technique for removing water from biological tissues, such as food samples. Cellular components freeze at once, and the ice sublimates under conditions of high vacuum and low temperatures. Because biological activity is restricted during FD, the degradation of cellular metabolites is often believed to be limited. However, the cellular structure is damaged by several factors, such as the increase in cell volume during freezing, and this has serious effects on the levels of some cellular metabolites. We studied these effects of FD on metabolite levels when using it as a sample preparation step in metabolome analysis. We observed significant decreases in the levels of some metabolites, such as succinate and choline, in Arabidopsis and pear, respectively. We also found that the effects of FD on certain metabolite levels differed between Arabidopsis plants and pear fruits. These results suggest that it is necessary to confirm the metabolite recovery in each sample species when FD is used for sample preparation.

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