RESUMO
The identification and characterization of pathogenicity factors are essential to an understanding of the molecular events that regulate the interaction of plant-pathogenic microbes with their hosts. We have isolated the gene that encodes a host-selective toxic protein produced by the fungus Pyrenophora tritici-repentis and confirmed that this gene functions in the plant as the primary determinant of pathogenicity in the Pyrenophora-wheat interaction. These results demonstrate that a single gene encodes the production of a host-selective toxin and that transformation of this gene into a non-toxin-producing isolate of P. tritici-repentis leads to both toxin production and pathogenicity.
Assuntos
Ascomicetos/patogenicidade , Proteínas Fúngicas , Micoses/genética , Micotoxinas/genética , Doenças das Plantas/genética , Sequência de Aminoácidos , Ascomicetos/genética , Sequência de Bases , Clonagem Molecular , DNA Complementar/química , Dados de Sequência Molecular , Micotoxinas/química , TriticumRESUMO
The purpose of the study was to investigate whether the thermal environment in which babies slept before developing haemorrhagic shock encephalopathy syndrome (HSES) differed from that of other babies. Data were collected by standardised interview from parents of 31 babies who had had HSES before the age of 7 months and compared with equivalent data for 124 control babies, with matching for outside temperature on the relevant night and for age. Multivariate analysis showed a strong association between HSES and covering of the baby's head by bedding, the odds ratio being 30.7 (95% confidence interval, 2.5 to 384). There were weaker associations with other aspects of the thermal environment. This suggests a link between HSES and some cases of cot death, supports the suggestion that HSES may be caused by overheating, and reinforces advice that babies should be placed to sleep in such a way that they are less likely to become totally covered.