Stability and modulated expression of a hygromycin resistance gene integrated in Botrytis cinerea transformants.

When transformation of Botrytis cinerea occurred in mononucleated protoplasts the hygromycin resistance phenotype was stable and integrated plasmid DNA although rearranged was transmitted through meiosis. We observed that transformants were often heterokaryotic and using serial conidial transfer, we showed failure of expression of the entire copies of integrated plasmids in some conidial isolates. A non-Mendelian segregation of the hygromycin resistance phenotype was observed in most crosses between these transformants and sensitive strains. However, a 1:1 segregation ratio of plasmid DNA hybridisation was observed. Mechanisms of gene silencing in B. cinerea, in both the asexual and the sexual cycle, are discussed.

Transformation of Botrytis cinerea with the hygromycin B resistance gene, hph.

A transformation method has been developed for the phytopathogenic fungus Botrytis cinerea. Protoplasts were transformed with pAN7-1 plasmid carrying the Escherichia coli hygromycin phosphotransferase gene (hph), conferring hygromycin B resistance, downstream from an Aspergillus nidulans promoter. Molecular analysis, showed that transformation resulted in an integration of the plasmid into different regions of the B. cinerea genome and occurred through non-homologous recombination. The frequency was 2-10 transformants per micrograms of DNA. Transformants expressed phosphotransferase activity confirming that the hph gene conferred the hygromycin-resistance phenotype. All transformants analysed so far proved to be stable after several subcultures without any selective pressure.

[Inhibitory effect of various hydrazine derivatives on the activity of L-phenylalanine ammonia-lyase from Rhodotorula glutinis]. / Effet inhibiteur de divers dérivés de l'hydrazine sur l'activité de la L-phénylalanine ammonialyase de Rhodotorula glutinis.

The inhibitory activities of hydrazinoacetic acid (HAA), 2-hydrazinoethanol (HE) and ethyl hydrazino-acetate (EHA) are characterized and compared with those of L-or D-alpha-hydrazino-beta-phenylpropionic acid (L-or D-HPPA), 2-phenylethylhydrazine (PEH), hydrazine (H), alpha, beta-dihydrocinnamic acid (DHCA) and D-phenylalanine (D-Phe). Inhibitors can be arranged in order of increasing activity: HE less than EHA less than H less than D-Phe less than HAA less than D-HPPA less than DHCA less than PEH less than L-HPPA. Relations between activity and structure of inhibitors are discussed.