RESUMEN
Filamentous ascomycetes contain large numbers of histidine kinases (HK) that belong to eleven classes. Members of class III from different species were previously shown to be involved in osmoregulation and resistance to dicarboximide and phenylpyrrole fungicides. We have inactivated the gene encoding the single group III HK, BOS1, in the economically important plant pathogen Botrytis cinerea. BOS1 inactivation had pleiotropic effects on the fungus. Besides the expected osmosensitivity and resistance to fungicides, null mutants presented additional characteristics indicating that BOS1 is necessary for normal macroconidiation and full virulence. On standard culture media, null mutants very rarely formed conidiophores and those few conidiophores failed to produce conidia. This defect could be partially restored with 1 M sorbitol, suggesting that another BOS1-independent signal cascade may be involved in macroconidiation. The mutants were not found to be hypersensitive to various oxidative stresses but were more resistant to menadione. Finally, pathogenicity tests showed that bos1-null mutants were significantly reduced in the ability to infect host plants. Appressorium morphogenesis was not altered; however, in planta growth was severely reduced. To our knowledge, this is the first class III HK characterized as a pathogenicity factor in a plant-pathogenic ascomycete.
Asunto(s)
Botrytis/genética , Proteínas Quinasas/genética , Factores de Virulencia/genética , Southern Blotting , Botrytis/efectos de los fármacos , Botrytis/patogenicidad , Medios de Cultivo/farmacología , Farmacorresistencia Fúngica/genética , Fabaceae/microbiología , Proteínas Fúngicas/genética , Fungicidas Industriales/farmacología , Histidina Quinasa , Solanum lycopersicum/microbiología , Malus/microbiología , Modelos Genéticos , Mutación/genética , Enfermedades de las Plantas/microbiología , Hojas de la Planta/microbiología , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/genética , Esporas Fúngicas/crecimiento & desarrollo , Virulencia/genéticaRESUMEN
The genus Pinguicula is one of the three genera of the carnivorous Lentibulariaceae, comprising approximately 80 species. Phylogeny inference using nucleotide sequences of the chloroplast gene matK and the trnK group II intron, as well as a set of 32 morphological characters revealed five well-supported, major lineages within the genus. These lineages largely reflect radiations in clearly defined geographic regions, whereas most previously recognized sections of the genus are shown to be para- or polyphyletic. A species-rich Mexican-Central American-Caribbean clade has the Eurasian P. alpina and an East Asian clade as successive sisters. All three are characterized by a production of flower buds on winter-resting plants, a specific corolla hair structure and a very large corolla lower central lobe. Another diverse clade is composed of species with primarily European distribution including the widespread type species P. vulgaris. For this clade, vegetative reproduction during dormancy is synapomorphic. Species native to SE North America and the South American Andes and a group of Mediterranean and NE Atlantic coast species together appear in a fifth well-supported clade, that is characterized by a tropical-type growth habit. It is the only clade that has reached temperate zones of the southern hemisphere.
