RESUMO
Earlier, we have reported that overexpression of Malus hupehensis Non-expressor of pathogenesis related gene 1 (MhNPR1) gene in tobacco could induce the expression of pathogenesis-related genes and enhance resistance to fungus Botrytis cinerea. In this study, we showed that MhNPR1 can be induced by NaCl, PEG6000, low temperature (4 °C), abscisic acid and apple aphids' treatments in M. hupehensis. Heterogonous expression of MhNPR1 gene in tobacco conferred enhanced resistance to NaCl at the stage of seed germination, and conferred resistance to mannitol at the stage of seed germination and to PEG6000 at the stage of seedlings. Furthermore, overexpression of MhNPR1 in transgenic tobacco led to higher expression levels of osmotic-stress related genes compared with wild-type plants. This was the first report of a novel function of NPR1 that overexpression of MhNPR1 gene has a positive effect on salt and osmotic stress in tobacco, which differs from the function that overexpressing of AtNPR1 gene has a negative effect on dehydration and salt stress in rice.
Assuntos
Proteínas de Arabidopsis/genética , Nicotiana/crescimento & desenvolvimento , Nicotiana/genética , Tolerância ao Sal/genética , Regulação da Expressão Gênica de Plantas , Malus/genética , Malus/metabolismo , Pressão Osmótica , Plantas Geneticamente Modificadas , Sais , Cloreto de SódioRESUMO
Fuji is susceptible to fungal diseases like apple powdery mildew. Non-expressor of pathogenesis-related gene 1 (NPR1) plays a key role in regulating salicylic acid (SA)-mediated systemic acquired resistance (SAR). Previous studies show that overexpressing the Malus hupehensis-derived NPR1 (MhNPR1) gene in tobacco induces the transcript expression of pathogenesis-related genes (PRs) and resistance to the fungus Botrytis cinerea. In this study we introduced the MhNPR1 gene into the 'Fuji' apple via Agrobacterium-mediated transformation. Four transgenic apple lines were verified by PCR and RT-PCR. The semi-quantitative RT-PCR results showed that transcript overexpression of the MhNPR1 gene induced the expression of MdPRs and MdMLO genes known to interact with powdery mildew. Furthermore, the transgenic apple plants resisted infection by apple powdery mildew better than the wild-type plants. As a result, transcript overexpression of the MhNPR1 gene induced SAR and enhanced the Fuji apple's resistance to fungal disease.
Assuntos
Malus/genética , Malus/imunologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Proteínas de Plantas/genética , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Malus/microbiologia , Fenótipo , Plantas Geneticamente ModificadasRESUMO
The tomato iron transporter gene (LeIRT2) was introduced to Malus robusta Rehd. via Agrobacterium-mediated transformation to produce iron-deficiency tolerant apple rootstock. A total of 19 putative transformants were obtained, 11 of which were verified by PCR amplification to carry a fragment of the transgene. Among them, nine were confirmed to carry the transgene by Southern blot analysis with one to three copies of the transgene integrated into the plant genome. Two transgenic plants, one carrying one copy and the other three copies of the transgene, were hydroponically cultured to test their tolerance to iron-deficiency, which was found only in the transgenic plant with a single copy, which weighted 21%-4% greater than those of the control plants.