The protein encoded by the FLOWERING LOCUS T (FT) gene from Arabidopsis thaliana seems to be the long-searched florigen, and over-expression of FT orthologues resulted in accelerated flower development in annual and perennial plants. In the present study, we isolated two allelic mRNA sequences of an FT-homologous gene from apple, which was designated as MdFT1. Using a SSR motif this gene was mapped on LG 12 of apple. Over-expression of MdFT1 in Arabidopsis and the commercially important tree species poplar and apple itself using the CaMV 35S or the Arabidopsis Suc2 promoter resulted in significant accelerated flowering compared with wild-type plants. Transgenic T(0) plants of Arabidopsis flowered 4-6 days on average earlier than wild-type Arabidopsis under LD conditions. Under short-day conditions Suc2::MdFT1 plants of the T(1)-generation flowered after 66 ± 18 days, while wild-type plants flowered about 22 days later. All transgenic Arabidopsis plants showed a normal habit except for the early flowering phenotype. Early flowering was detected 6-10 months after transformation in transgenic polar clones containing MdFT1 driven by the CaMV 35S, whereas plants of the transgenic apple clone T780 set up its first flowers during in vitro cultivation. Based on our results we conclude that MdFT1 is responsible for inducing flowering and that the function of the apple FT1 gene is conserved in annual herbaceous species as well as perennial woody species. Furthermore, we discuss the role of MdFT1 in flower development with regard to the findings of genetic studies on apple.

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In order to compare transcription profiles in cultivars of Malus domestica that are differentially sensitive to apple scab (Venturia inaequalis), two cDNA libraries were constructed using the suppression subtractive hybridization (SSH) method. Subtraction hybridization was performed between cDNAs from uninfected young leaves of the resistant cultivar Remo and the susceptible Elstar. In total, 480 EST clones were obtained: 218 (ELSTAR) clones represent transcripts that are preferentially expressed in Elstar, while the other 262 (REMO) are derived from RNAs that are more highly expressed in Remo. The putative functions of about 50% of the cloned sequences could be identified by sequencing and subsequent homology searches in databases or by dot-blot hybridization to known targets. In the resistant cv. Remo the levels of transcripts encoding a number of proteins related to plant defense (such as beta-1,3-glucanase, ribonuclease-like PR10, cysteine protease inhibitor, endochitinase, ferrochelatase, and ADP-ribosylation factor) or detoxification of reactive oxygen species (such as superoxide dismutase) were highly up-regulated relative to the amounts present in cv. Elstar. Most surprising was the large number of clones derived from mRNAs for metallothioneins of type 3 (91 out of 262) found in the REMO population. The corresponding transcripts were only present in small amounts in young uninfected leaves of the cv. Elstar, but were up-regulated in the susceptible cultivar after inoculation with V. inaequalis. These results indicate that constitutively high-level expression of PR proteins may protect cv. Remo from infection by different plant pathogens.

Grain legumes are regarded as highly valuable protein source for human and animal nutrition. Legume protein quality is mainly limited by the amino acids (AAs) tryptophan and sulphur AA. Organic farming in particular requires high seed protein quality for livestock feeding, as chemically produced AAs must not be feeded. Breeding attempts to increase contents of limiting AA are required. In the present survey, the AA content of 107 cultivars of important European grain legume species (Lupinus angustifolius, Lupinus luteus, Pisum sativum and Vicia faba) was analysed. AA contents were related to the requirements of growing pigs and human nutrition. Feed quality could be enhanced by choice of high quality varieties according to ideal protein concepts. For example for sulphur, AA feed quality for pigs could be increased by up to 22% (e.g. for L. angustifolius: ideal protein = 100, sample mean = 59.7, sample maximum = 72.7). Regarding livestock nutrition, ranges of limiting AA never reached the qualities reported for soybean seeds. However, an inclusion of high quality legume lines would reduce the need for other high quality components in feed compositions.

A plant lectin was isolated from barley (Hordeum vulgare) coleoptiles using acidic extraction and different chromatographic methods. Sequencing of more than 50% of the protein sequence by Edman degradation confirmed a full-length cDNA clone. The subsequently identified open reading frame encodes for a 15 kDa protein which could be found in the soluble fraction of barley coleoptiles. This protein exhibited specificity towards mannose sugar and is therefore, accordingly named as Horcolin (Hordeum vulgare coleoptile lectin). Database searches performed with the Horcolin protein sequence revealed a sequence and structure homology to the lectin family of jacalin-related lectins. Together with its affinity towards mannose, Horcolin is now identified as a new member of the mannose specific subgroup of jacalin-related lectins in monocot species. Horcolin shares a high amino acid homology to the highly light-inducible protein HL#2 and, in addition to two methyl jasmonic acid-inducible proteins of 32.6 and 32.7 kDa where the jasmonic acid-inducible proteins are examples of bitopic chimerolectins containing a dirigent and jacalin-related domain. Immunoblot analysis with a cross-reactive anti-HL#2 antibody in combination with Northern blot analysis of the Horcolin cDNA revealed tissue specific expression of Horcolin in the coleoptiles. The function of Horcolin is discussed in the context of its particular expression in coleoptiles and is then compared to other lectins, which apparently share a related response to biotic or abiotic stress factors.