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The two FLOWERING LOCUS T (FT)-like genes of apple (Malus × domestica Borkh.), MdFT1 and MdFT2, have been isolated and characterized. MdFT1 and MdFT2 were mapped, respectively, on distinct linkage groups (LGs) with partial homoeology, LG 12 and LG 4. The expression pattern of MdFT1 and MdFT2 differed in that MdFT1 was expressed mainly in apical buds of fruit-bearing shoots in the adult phase, with little expression in the juvenile tissues, whereas MdFT2 was expressed mainly in reproductive organs, including flower buds and young fruit. On the other hand, both genes had the potential to induce early flowering since transgenic Arabidopsis, which ectopically expressed MdFT1 or MdFT2, flowered earlier than wild-type plants. Furthermore, overexpression of MdFT1 conferred precocious flowering in apple, with altered expression of other endogenous genes, such as MdMADS12. These results suggest that MdFT1 could function to promote flowering by altering the expression of those genes and that, at least, other genes may play an important role as well in the regulation of flowering in apple. The long juvenile period of fruit trees prevents early cropping and efficient breeding. Our findings will be useful information to unveil the molecular mechanism of flowering and to develop methods to shorten the juvenile period in various fruit trees, including apple. [ABSTRACT FROM PUBLISHER]

Abstract: Parthenocarpy—the production of seedless fruits without fertilization—is very useful for fruit cultivation, especially in self-incompatible species such as pears. To search for parthenocarpic genetic resources in pear, 31 pear accessions [20 Chinese pears (13 Pyrus bretschneideri, seven Pyrus ussuriensis), five European pears (Pyrus communis), two Japanese pears (Pyrus pyrifolia), and four interspecific hybrids] were subjected to flower emasculation and left unpollinated, and then the fruit-set ratio and fruit enlargement were investigated. All European pears examined had a stable and high degree of fruit set, and ‘La France’ had high fruit enlargement. The possibility of stenospermocarpy was ruled out, because the emasculated flowers were left unpollinated in paper bags and the absence of seed was confirmed in the enlarged fruits. Neither Chinese nor Japanese pears treated with emasculation and no pollination showed consistently stable fruit set and fruit enlargement. An analysis of parthenocarpy in the offspring of ‘La France’ suggested that both high fruit set and fruit enlargement were inherited and that it should be possible to introduce parthenocarpy into Japanese pears. Although parthenocarpic ‘La France’ fruits weighed slightly less than those from cross-pollinated flowers, their cortex enlargement compared favorably with that seen with cross-pollinated ones. By using a customized pear cDNA microarray, we compared the gene expression profiles of highly and weakly parthenocarpic cultivars before flowering. Expression of several phenylpropanoid-related genes and photosystem-related genes differed significantly between the two groups. Some of these genes were putatively encoded in the chloroplast genome. These genes might be candidates of DNA markers for achievement of parthenocarpy in Japanese pear breeding. [Copyright &y& Elsevier]