RESUMEN
Aluminum (Al) toxicity is the main factor limiting plant growth and the yield of cereal crops in acidic soils. Al-induced oxidative stress could lead to the excessive accumulation of reactive oxygen species (ROS) and aldehydes in plants. Aldehyde dehydrogenase (ALDH) genes, which play an important role in detoxification of aldehydes when exposed to abiotic stress, have been identified in most species. However, little is known about the function of this gene family in the response to Al stress. Here, we identified an ALDH gene in maize, ZmALDH, involved in protection against Al-induced oxidative stress. Al stress up-regulated ZmALDH expression in both the roots and leaves. The expression of ZmALDH only responded to Al toxicity but not to other stresses including low pH and other metals. The heterologous overexpression of ZmALDH in Arabidopsis increased Al tolerance by promoting the ascorbate-glutathione cycle, increasing the transcript levels of antioxidant enzyme genes as well as the activities of their products, reducing MDA, and increasing free proline synthesis. The overexpression of ZmALDH also reduced Al accumulation in roots. Taken together, these findings suggest that ZmALDH participates in Al-induced oxidative stress and Al accumulation in roots, conferring Al tolerance in transgenic Arabidopsis.
Asunto(s)
Adaptación Fisiológica/genética , Aldehído Deshidrogenasa/genética , Aluminio/toxicidad , Arabidopsis/genética , Arabidopsis/fisiología , Genes de Plantas , Zea mays/genética , Adaptación Fisiológica/efectos de los fármacos , Aldehído Deshidrogenasa/química , Aldehído Deshidrogenasa/metabolismo , Secuencia de Aminoácidos , Antioxidantes/metabolismo , Arabidopsis/efectos de los fármacos , Ascorbato Peroxidasas/metabolismo , Ácido Ascórbico/metabolismo , Clonación Molecular , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Glutatión/metabolismo , Glutatión Reductasa/metabolismo , Peróxido de Hidrógeno/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Filogenia , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Plantas Modificadas Genéticamente , Prolina/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Fracciones Subcelulares/metabolismo , Superóxidos/metabolismo , Nicotiana/metabolismoRESUMEN
The Agrobacterium-mediated transformation system is more and more attractive to scientists of microbiology, molecular biology and crop genetics and breeding due to its unique advantages, which promote its development rapidly in the past decade. Great success has been achieved in the Agrobacterium-mediated genetic transformation system in maize (Zea mays L.), an important food-supply crop. This article highlights the advances of Agrobacterium-mediated transformation system of maize and the major factors of the transformation process. Then, comments on the problems remained and the prospects of this transformation system are made.
Asunto(s)
Transformación Genética , Zea mays , Agrobacterium/genética , Agrobacterium tumefaciens/genética , Plantas Modificadas Genéticamente/genética , Zea mays/genéticaRESUMEN
Using an estrogen-inducible expression XVE (LexA-VP16-Estragon Receptor) system, we have generated approximately 40 000 independent T-DNA insertion lines of Arabidopsis thaliana. Segregation analyses of about 18000 lines indicated that 51.6% of them contain single T-DNA insertions and that the average insertion number is 1.38 copies per line. Mutants displaying a variety of morphological alterations were identified, including those that affect development of roots,hypocotyls, leaves, floral organs and seeds as well as the flowering time.
Asunto(s)
Arabidopsis/genética , ADN Bacteriano/genética , Mutagénesis Insercional/métodos , Plantas Modificadas Genéticamente/genética , Arabidopsis/anatomía & histología , Arabidopsis/crecimiento & desarrollo , Proteínas Bacterianas/genética , Clonación Molecular , Estrógenos/farmacología , Vectores Genéticos/genética , Proteína Vmw65 de Virus del Herpes Simple/genética , Mutagénesis Insercional/efectos de los fármacos , Fenotipo , Plantas Modificadas Genéticamente/anatomía & histología , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Plásmidos/genética , Receptores de Estrógenos/genética , Serina Endopeptidasas/genética , Activación Transcripcional/efectos de los fármacosRESUMEN
Antifreeze proteins are a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival under the subzero environments. Ammopiptanthus nanus is the unique evergreen broadleaf bush endemic to the Mid-Asia deserts. It survives at the west edge of the Tarim Basin from the disappearance of the ancient Mediterranean in the Tertiary Period. Its distribution region is characterized by the arid climate and extreme temperatures, where the extreme temperatures range from -30 °C to 40 °C. In the present study, the antifreeze protein gene AnAFP of A. nanus was used to transform Escherichia coli and tobacco, after bioinformatics analysis for its possible function. The transformed E. coli strain expressed the heterologous AnAFP gene under the induction of isopropyl ß-D-thiogalactopyranoside, and demonstrated significant enhancement of cold tolerance. The transformed tobacco lines expressed the heterologous AnAFP gene in response to cold stress, and showed a less change of relative electrical conductivity under cold stress, and a less wilting phenotype after 16 h of -3 °C cold stress and thawing for 1h than the untransformed wild-type plants. All these results imply the potential value of the AnAFP gene to be used in genetic modification of commercially important crops for improvement of cold tolerance.
Asunto(s)
Proteínas Anticongelantes/genética , Respuesta al Choque por Frío/genética , Escherichia coli/genética , Fabaceae/genética , Nicotiana/genética , Adaptación Fisiológica/genética , Proteínas Anticongelantes/biosíntesis , Proteínas Anticongelantes/metabolismo , Frío/efectos adversos , Escherichia coli/citología , Escherichia coli/metabolismo , Fabaceae/metabolismo , Congelación , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Regiones Promotoras Genéticas , Nicotiana/citología , Nicotiana/metabolismo , Transformación GenéticaRESUMEN
Aluminum (Al) stress is one of the most important factors affecting the plant growth on acid soil. Currently, global soil acidification further intensifies the Al stress. Plants can detoxify Al via the chelation of ionic Al and organic acids to store the ionic Al in vacuoles and extrude it from roots. The Al extrusion is mainly performed by the membrane-localized anion channel proteins Al(3+)-activated malate transporter (ALMT) and multi-drug and toxin extrusion (MATE). The genes encoding ABC transporter and zinc-finger protein conferred plant Al tolerance have also been found. The identification of these Al-resistant genes makes it possible to increase the Al resistance of crop plants and enhance their production by the biological methods such as gene transformation and mark-associated breeding. The key problems needed to be solved and the possible directions in the researches of plant Al stress resistance were proposed.