In order to expand gene resources and improve Brassica napus cultivars, protoplasts isolated from hypocotyls of Brassica napus cv. Huayou No. 3 and Eruca sativa were fused by PEG-high Ca2+-high pH. Fusion frequency was up to 18.2% when fusion system contained 5 x 10(5) protoplasts/mL, and when PEG concentration of fusion agents were 35% and when fusion time was 25 min. Then the fused protoplasts were cultured by the method of thin liquid layer at the density of 1 x 10(5) protoplasts/mL in improved KM8p medium supplemented with 1.0 mg/L 2,4-D, 0.5 mg/L NAA, 0.5 mg/L 6-BA, 200 mg/L inositol, 300 mg/L protein hydrolysate, and the combinations of 0.1 mol/L sucrose and 0.2 mol/L glucose and 0.2 mol/L mannitol for osmotic regulator, the frequency of callus regeneration was up to 6.8%. When the micro-calli transferred to the proliferation medium that contained B5 salts, 0.087 mol/L sucrose, 0.2 mg/L 2,4-D, 0.5 mg/L NAA, 0.2 mg/L 6-BA and 0.5% Agar, pH 5.8, have grown up to 3-5 mm of diameter, the calli were transferred to the differentiation medium that contained MS salts, 0.087 mol/L sucrose, 0.1 mg/L IAA, 0.8 mg/L 6-BA, 0.8% Agar, pH5.8, the shoots were regenerated in 4 weeks and its frequency was up to 32.8%. Then 2-3 cm shoots were transferred to 1/2 MS medium with 0.5 mg/L IBA+0.2mg/L 6-BA, plantlets were obtained in 14 days and the plantlet frequency was up to 88%. When the protoplasts of Eruca sativa were treated with UV radiation for 2 minutes calli and plantlets have been regenerated, treated for 4 min only calli have been regenerated, and treated for more than 5 min calli have not been regenerated. The callus regeneration and callus proliferation and plant regeneration from symmetric fusion were more than from asymmetric fusion. 16 hybrid plantlets have been regenerated on 21 piece of hybrid calli identified by cytology method.
Brassica ; genetics ; Brassicaceae ; genetics ; Cell Fusion ; Hybrid Cells ; Hybridization, Genetic ; Protoplasts ; Regeneration ; Ultraviolet Rays

The dynamic activity of transposable elements (TEs) contributes to the vast diversity of genome size and architecture among plants. Here, we examined the genomic distribution and transposition activity of long terminal repeat retrotransposons (LTR-RTs) in Arabidopsis thaliana (Ath) and three of its relatives, Arabidopsis lyrata (Aly), Eutrema salsugineum (Esa), and Schrenkiella parvula (Spa), in Brassicaceae. Our analyses revealed the distinct evolutionary dynamics of Gypsyretrotransposons, which reflects the different patterns of genome size changes of the four species over the past million years. The rate of Gypsy transposition in Aly is approximately five times more rapid than that of Ath and Esa, suggesting an expanding Aly genome. Gypsy insertions in Esa are strictly confined to pericentromeric heterochromatin and associated with dramatic centromere expansion. In contrast, Gypsy insertions in Spa have been largely suppressed over the last million years, likely as a result of a combination of an inherent molecular mechanism of preferential DNA removal and purifying selection at Gypsy elements. Additionally, species-specific clades of Gypsy elements shaped the distinct genome architectures of Aly and Esa.
Brassicaceae/genetics* ; Evolution, Molecular ; Genome Size ; Genome, Plant ; Genomics ; Phylogeny ; Retroelements ; Species Specificity

Vernalization makes Arabidopsis and other cruciferous plants flowering earlier. During this process, an important plant homeodomain-finger(PHD-finger) protein named VIN3 is involved. The PHD domain was a conserved zinc-finger domain in eukaryotic organism. It used to take part in the interaction between proteins, especially the modification on histone of nucleosome, such as methylation, acetylation and phosphorylation. In vernaliazation pathway, the proteins translated by VERNALIZATION INSENSITIVE 3(VIN3) and homologous genes could result in methylation on H3K9 and H3K27 and deacetylation on H3K9 and H3K14 on chromatin histone of FLOWERING LOCUS C, a gene that inhibited flowering. The structure state of FLC would be changed from relaxation into compression. Then the transcription activity of FLC could be restrained and it couldn't inhibit flowering any more, so it would induce flowering earlier. This paper reviewed the function of PHD-finger proteins in vernalization pathway in Arabidopsis and other cruciferous plants, and overviewed the vernalization mechanism.
Amino Acid Sequence ; Arabidopsis ; genetics ; metabolism ; Arabidopsis Proteins ; genetics ; metabolism ; physiology ; Brassicaceae ; genetics ; DNA-Binding Proteins ; genetics ; metabolism ; physiology ; Gene Expression Regulation, Plant ; genetics ; physiology ; Histones ; metabolism ; Homeodomain Proteins ; genetics ; metabolism ; physiology ; MADS Domain Proteins ; genetics ; metabolism ; Molecular Sequence Data ; Transcription Factors ; genetics ; metabolism ; physiology ; Zinc Fingers