Se estudian cariologicamente los distintos taxones del genero Coincya en la Peninsula Iberica. Se indica por primera vez el numero cromosomico de C. transtagana (n=12, 2n=24). El nivel tetraploide es nuevo para los siguientes taxones: C. longirostra (n=24), C. rupestris subsp. leptocarpa (n=24) y C. monensis subsp. cheiranthos var. setigera (n=24).

Myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1.) is in Brassicaceae species such as Brassica napus and Sinapis alba encoded by two differentially expressed gene families, MA and MB, consisting of about 4 and 10 genes, respectively. Southern blot analysis showed that Arabidopsis thaliana contains three myrosinase genes . These genes were isolated from a genomic library and two of them, TGG1 and TGG2, were sequenced. They were found to be located in an inverted mode with their 3' ends 4.4 kb apart. Their organization was highly conserved with 12 exons and 11 short introns. Comparison of nucleotide sequences of TGG1 and TGG2 exons revealed an overall 75% similarity. In contrast, the overall nucleotide sequence similarity in introns was only 42%. In intron 1 the unusual 5' splice border GC was used. Phylogenetic analyses using both distance matrix and parsimony programs suggested that the Arabidopsis genes could not be grouped with either MA or MB genes. Consequently, these two gene families arose only after Arabidopsis had diverged from the other Brassicaceae species. In situ hybridization experiments showed that TGG1 and TGG2 expressing cells are present in leaf, sepal, petal, and gynoecium. In developing seeds, a few cells reacting with the TGG1 probe, but not with the TGG2 probe, were found indicating a partly different expression of these genes.

To understand the genetic regulation of vegetative to reproductive transition in higher plants, further characterization of the Arabidopsis mutant embryonic flower1, emf1, was conducted. Using three flowering symptoms, we showed that emf1 mutants could only grow reproductive and not rosette shoots under five different growth conditions. The mutant embryos did not produce the typical tunica-corpus shoot apical structures at the heart-, torpedo-, and mature stages. The divergent shoot apical development during mutant and wild-type embryogenesis indicated that the wild-type EMF1 gene was expressed in early embryogenesis. Mutations in the EMF1 gene affected the embryonic shoot apical development and caused the germinating embryo and regenerating callus to grow inflorescence, instead of rosette, shoots. Our results support the hypothesis that the EMF1 gene regulates the switch between vegetative and reproductive growth in Arabidopsis.

Myrosinase (thioglucosidase glucohydrolase; EC 3.2.3.1) is a group of isoenzymes in the Brassicaceae, which hydrolyze glucosinolates. Genes encoding myrosinase contain 12 exons and 11 introns. Sequence comparison of two myrosinase genes from Arabidopsis thaliana, TGG1 and TGG2, with the corresponding cDNA from leaves, showed preferential use of a GC dinucleotide as the 5' splicing border in intron 1 instead of an adjacent GT dinucleotide four bp further 3'. This 5' GC splice site is conserved in all seven myrosinase genes characterized from three different species. Likewise, in the 3' region of intron 1 two AG dinucleotides are located seven bp apart. Only the most 5' of these dinucleotides was found to be used in splicing. Sequence analyses of TGG1 cDNA isolated from seeds, siliques and vegetative tissue using reverse transcription PCR showed that the splicing pattern of this intron is identical in these tissues for TGG1. The GT and the most 3' AG dinucleotides mentioned above have been assumed to be the intron borders of intron 1 in several myrosinase genes. The present investigation shows that this assumption is not correct.

In greenhouse and field experiments one genotype from the species Brassica carinata, Brassica juncea, Brassica nigra and Sinapis alba were investigated with the aim of clarifying, whether these species are fundamentally suitable for the erucic acid production as an alternative to B. napus due to their superior content in this acid and ability to tolerate pests, diseases and drought. In the field experiment B. napus ssp. oleifera f. annua was included. The yield related parameters were examined with increasing nitrogen application. In addition, seeds were analysed with respect to quality parameters in response to the nitrogen application. B. carinata was superior in seed yield compared to the other Brassicaceae under greenhouse conditions. In field experiment, B. napus ssp. oleifera f. annua and S. alba realised higher yield whereas the comparatively low Harvest-lndex of B. carinata accounted for the lower seed yield in this genotype. B. juncea showed the highest oil and erucic acid content in the seed (38,8% of DM and 49,8% of the oil content respectively). However, a strong drop in productivity was recorded for this genotype in the field in comparison to the greenhouse, and the cause was believed to be poor phytosanitary condition. B. nipra reached a significantly lower level (P = 0.01) in oil and erucic acid content and in the seed yield in comparison to the other Brassicaceae. S. alba produced at medium seed yield level the lowest oil and erucic acid content in the seed nonetheless this species showed relatively high protein content (31,3% of DM). The fatty acid composition of the seeds of S. alba showed a remarkable difference to the Brassica species. S. alba had a reduced linoleic and linolenic acid content although the species showed up to threefold higher oleic acid content.

In greenhouse and field experiments one genotype from the species Brassica carinata, Brassica juncea, Brassica nigra and Sinapis alba were investigated with the aim of clarifying, whether these species are fundamentally suitable for the erucic acid production as an alternative to B. napus due to their superior content in this acid and ability to tolerate pests, diseases and drought. In the field experiment B. napus ssp. oleifera f. annua was included. The yield related parameters were examined with increasing nitrogen application. In addition, seeds were analysed with respect to quality parameters in response to the nitrogen application. B. carinata was superior in seed yield compared to the other Brassicaceae under greenhouse conditions. In field experiment, B. napus ssp. oleifera f. annua and S. alba realised higher yield whereas the comparatively low Harvest-lndex of B. carinata accounted for the lower seed yield in this genotype. B. juncea showed the highest oil and erucic acid content in the seed (38,8% of DM and 49,8% of the oil content respectively). However, a strong drop in productivity was recorded for this genotype in the field in comparison to the greenhouse, and the cause was believed to be poor phytosanitary condition. B. nipra reached a significantly lower level (P = 0.01) in oil and erucic acid content and in the seed yield in comparison to the other Brassicaceae. S. alba produced at medium seed yield level the lowest oil and erucic acid content in the seed nonetheless this species showed relatively high protein content (31,3% of DM). The fatty acid composition of the seeds of S. alba showed a remarkable difference to the Brassica species. S. alba had a reduced linoleic and linolenic acid content although the species showed up to threefold higher oleic acid content.

Myrosinase-binding proteins (MBPs) were purified from seeds of Brassica napus L. (oilseed rape). The proteins were characterized with respect to amino-acid composition, peptide sequence and isoelectric points. Gel electrophoresis and Western blotting of protein extracts from mature seeds showed the existence of at least ten proteins reacting with a monoclonal anti-MBP antibody and ranging in molecular size from 110 to 30 kDa. Proteins other than MBP reacting with the anti-MBP antibody were assigned as myrosinase-binding protein-related proteins (MBPRPs). Two MBPRPs were purified by immunoaffinity chromatography and characterized with respect to partial amino-acid sequence. Sequence identities were found between MBP and MBPRP. Western blot analysis of protein extracts from different tissues of B. napus showed that MBPRP is present in the whole plant, whereas MBP mostly occurs in the mature seed. A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) was used to investigate the occurrence of MBP and MBPRP in developing seeds of some species in the Brassicaceae family.