Integration of BpMADS4 on various linkage groups improves the utilization of the rapid cycle breeding system in apple

Rapid cycle breeding in apple is a new approach for the rapid introgression of agronomically relevant traits (e.g. disease resistances) from wild apple species into domestic apple cultivars (Malus × domestica Borkh.). This technique drastically shortens the long‐lasting juvenile phase of apple. The utilization of early‐flowering apple lines overexpressing the BpMADS4 gene of the European silver birch (Betula pendula Roth.) in hybridization resulted in one breeding cycle per year. Aiming for the selection of non‐transgenic null segregants at the end of the breeding process, the flower‐inducing transgene and the gene of interest (e.g. resistance gene) that will be introgressed by hybridization need to be located on different chromosomes. To improve the flexibility of the existing approach in apple, this study was focused on the development and characterization of eleven additional BpMADS4 overexpressing lines of four different apple cultivars. In nine lines, the flowering gene was mapped to different linkage groups. The differences in introgressed T‐DNA sequences and plant genome deletions post‐transformation highlighted the unique molecular character of each line. However, transgenic lines demonstrated no significant differences in flower organ development and pollen functionality compared with non‐transgenic plants. Hybridization studies using pollen from the fire blight‐resistant wild species accession Malus fusca MAL0045 and the apple scab‐resistant cultivar ‘Regia’ indicated that BpMADS4 introgression had no significant effect on the breeding value of each transgenic line.     

Evidence for reductive genome evolution and lateral acquisition of virulence functions in two Corynebacterium pseudotuberculosis strains

Background

Corynebacterium pseudotuberculosis, a Gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity.

Methodology and Findings

We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer.

Conclusions

These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/genbank/) under accession numbers {"type":"entrez-nucleotide","attrs":{"text":"CP001809","term_id":"340539261","term_text":"CP001809"}}CP001809 and {"type":"entrez-nucleotide","attrs":{"text":"CP001829","term_id":"302205157","term_text":"CP001829"}}CP001829.     

Frequency of lactase persistence genotype in a healthy Polish population

The majority of mammals are unable to digest lactose due to post-weaning deactivation of the LCT gene, which is responsible for encoding the enzyme lactase (i.e., adult-type hypolactasia). A substitution of C with T at position −13910 bp upstream of the LCT gene has been linked to the lactase persistence phenotype in European populations. We investigated the frequency of LCT-13910C>T polymorphism in 223 blood donors from central Poland. All samples were genotyped by polymerase chain reaction and direct sequencing. The LCT-13910 T allele (lactase persistence) was present in 51% of individuals sampled from the Polish population. We did not find any non-European variants associated with lactase persistence (LCT-13907C>G, LCT-13913T>C, LCT-13915T>G), or any new polymorphisms within the sequenced region. Allele frequencies obtained are in agreement with results from other countries and confirm the unique pattern of distribution of the LCT-13910C>T genotype in Europe.     

Advancing cartilage tissue engineering: the application of stem cell technology

The treatment of cartilage pathology and trauma face the challenges of poor regenerative potential and inferior repair. Nevertheless, recent advances in tissue engineering indicate that adult stem cells could provide a source of chondrocytes for tissue engineering that the isolation of mature chondrocytes has failed to achieve. Various adjuncts to their propagation and differentiation have been explored, such as biomaterials, bioreactors and growth hormones. To date, all tissue engineered cartilage has been significantly mechanically inferior to its natural counterparts and further problems in vivo relate to poor integration and deterioration of tissue quality over time. However, adult stem cells--with their high rate of proliferation and ease of isolation--are expected to greatly further the development and usefulness of tissue engineered cartilage.     

Heavy metals and thiol pool in three strains of <Emphasis Type="Italic">Tetracladium marchalianum</Emphasis>

Growth of three strains of Tetracladium marchalianum was inhibited by Cd-, and, to a lesser extent, by Cu-and Zn-chloride. In the presence of 50 μM Cd(II), all strains increased total thiol and glutathione production to 6, 11, and 21 μmoles · mg⁻¹ dry mass, respectively. Cd(II) also induced the synthesis of one to several compounds reacting with 5,5′-dithio-bis-(2-nitrobenzoic acid). In order to identify buffer-soluble thiolic compounds other than cysteine, γ-EC and γ-ECG (glutathione) were analyzed and confirmed by mass spectrometry. No water soluble sulfides were detectable in any of the culture filtrates, but Cd(II) exposure at a concentration of 50 μM raised sulfide levels in the mycelia of two of the strains between 3 and 7-fold, Cu(II) and Zn(II) had no effect. Energy Dispersive X-ray-analysis (EDX) and Electron Spectrometry-Images (ES-I) of one strain revealed increased levels of Cu and Zn in the cytoplasm and even higher levels in vacuolar precipitates. Zn and Cu are accumulated in the vacuoles as polyphosphates, identified by Electron Energy Loss-Spectrometry (EELS). Cd was found only in the vacuoles.     

Methylotrophic extremophilic yeast Trichosporon sp.: a soil-derived isolate with potential applications in environmental biotechnology

A yeast isolate revealing unique enzymatic activities and substrate-dependent polymorphism was obtained from autochthonous microflora of soil heavily polluted with oily slurries. By means of standard yeast identification procedures the strain was identified as Trichosporon cutaneum. Further molecular PCR product analyses of ribosomal DNA confirmed the identity of the isolate with the genus Trichosporon. As it grew on methanol as a sole carbon source, the strain appeared to be methylotrophic. Furthermore, it was also able to utilize formaldehyde. A multi-substrate growth potential was shown with several other carbon sources: glucose, glycerol, ethanol as well as petroleum derivatives and phenol. Optimum growth temperature was determined at 25 degrees C, and strong inhibition of growth at 37 degrees C together with the original soil habitat indicated lack of pathogenicity in warm-blooded animals and humans. The unusually high tolerance to xenobiotics such as diesel oil (>30 g/l), methanol (50 g/l), phenol (2 g/l) and formaldehyde (7.5 g/l) proved that the isolate was an extremophilic organism. With high-density cultures, formaldehyde was totally removed at initial concentrations up to 7.5 g/l within 24 h, which is the highest biodegradation capability ever reported. Partial biodegradation of methanol (13 g/l) and diesel fuel (20 g/l) was also observed. Enzymatic studies revealed atypical methylotrophic pathway reactions, lacking alcohol oxidase, as compared with the conventional methylotroph Hansenula polymorpha. However, the activities of glutathione-dependent formaldehyde dehydrogenase, formaldehyde reductase, formate dehydrogenase and unspecific aldehyde dehydrogenase(s) were present. An additional glutathione-dependent aldehyde dehydrogenase activity was also detected. Metabolic and biochemical characteristics of the isolated yeast open up new possibilities for environmental biotechnology. Some potential applications in soil bioremediation and wastewater decontamination are discussed.