Mechanisms controlling the selective iron and zinc biofortification of rice

L’arròs es un cultiu bàsic, consumit per mes de 3 billons de persones. Es una font pobra en ferro (Fe) i zinc (Zn) per la qual cosa les poblacions pobres que depenen de l’arros per a la seva supervivència, sofreixen d’anèmia por deficiència de ferro (IDA) i zinc (ZnD). La desnutrició es un repte important, especialment en els països en desenvolupament on no hi ha les mesures nutritives comunes als països industrialitzats (una dieta variada, programes de fortificació i suplements dietètics). El bio-enriquiment mitjançant l’enginyeria genètica del contingut de Fe y Zn en arròs es una estratègia prometedora y pot resultar en un augmentant de les seves concentracions. Amb l’objectiu d’aconseguir arròs que acumuli nivells mes elevats de Fe y Zn he obtingut una població d’arròs transgènic mitjançant transformació combinatòria amb quatre gens implicats en l’absorció, transport, acumulació i biodisponibilitat d’aquestos dos minerals. Aquesta població combinatòria m’ha servit per a identificar els mecanismes antagònics i sinèrgics que son essencials per a controlar l’acumulació de Fe i Zn.El arroz es un cultivo básico para más de 3 billones de personas. El arroz es una fuente pobre de hierro (Fe) y zinc (Zn) por lo cual las poblaciones pobres que dependen del arroz para su supervivencia, sufren de anemia por deficiencia de hierro (IDA) y zinc (ZnD). La desnutrición es un reto importante, especialmente en los países en desarrollo donde están ausentes las medidas que son comunes en los países industrializados (dieta variada, programas de fortificación y suplementos dietéticos). El bio-enriquecimiento mediante la ingeniería genética del contenido de Fe y Zn en arroz es una estrategia prometedora para aumentar sus concentraciones. Con el objetivo de producir granos con más alto nivel de Fe y Zn he obtenido una población de arroz transgénico mediante transformación combinatoria con cuatro genes implicados en la absorción, transporte, acumulación y biodisponibilidad de estos dos minerales. Esta población combinatoria me sirvió para identificar los mecanismos antagónicos y sinérgicos que son esenciales para controlar la acumulación de Fe y Zn.Rice is staple crop for more than 3 billion people, since rice is poor source of iron (Fe) and zinc (Zn) world’s poorest people who depend on rice for their survival suffer from iron deficiency anaemia (IDA) and zinc deficiency (ZnD). Malnutrition is a significant challenge, particularly in the developing world where measures that are commonplace in industrialized countries (varied diet, fortification schemes, and dietary supplements) are largely absent. Biofortification of rice with Fe and Zn by genetic engineering is a promising strategy to increase Fe and Zn concentration. I established a combinatorial transgenic rice population by transformation with four genes involved in uptake, transport, accumulation and bioavailability of Fe and Zn, aiming to produce grains containing higher level of these two minerals. This combinatorial population helped to identify key antagonistic and synergistic mechanisms controlling Fe and Zn accumulation

Mechanisms controlling the selective iron and zinc biofortification of rice

L’arròs es un cultiu bàsic, consumit per mes de 3 billons de persones. Es una font pobra en ferro (Fe) i zinc (Zn) per la qual cosa les poblacions pobres que depenen de l’arros per a la seva supervivència, sofreixen d’anèmia por deficiència de ferro (IDA) i zinc (ZnD). La desnutrició es un repte important, especialment en els països en desenvolupament on no hi ha les mesures nutritives comunes als països industrialitzats (una dieta variada, programes de fortificació i suplements dietètics). El bio-enriquiment mitjançant l’enginyeria genètica del contingut de Fe y Zn en arròs es una estratègia prometedora y pot resultar en un augmentant de les seves concentracions. Amb l’objectiu d’aconseguir arròs que acumuli nivells mes elevats de Fe y Zn he obtingut una població d’arròs transgènic mitjançant transformació combinatòria amb quatre gens implicats en l’absorció, transport, acumulació i biodisponibilitat d’aquestos dos minerals. Aquesta població combinatòria m’ha servit per a identificar els mecanismes antagònics i sinèrgics que son essencials per a controlar l’acumulació de Fe i Zn.El arroz es un cultivo básico para más de 3 billones de personas. El arroz es una fuente pobre de hierro (Fe) y zinc (Zn) por lo cual las poblaciones pobres que dependen del arroz para su supervivencia, sufren de anemia por deficiencia de hierro (IDA) y zinc (ZnD). La desnutrición es un reto importante, especialmente en los países en desarrollo donde están ausentes las medidas que son comunes en los países industrializados (dieta variada, programas de fortificación y suplementos dietéticos). El bio-enriquecimiento mediante la ingeniería genética del contenido de Fe y Zn en arroz es una estrategia prometedora para aumentar sus concentraciones. Con el objetivo de producir granos con más alto nivel de Fe y Zn he obtenido una población de arroz transgénico mediante transformación combinatoria con cuatro genes implicados en la absorción, transporte, acumulación y biodisponibilidad de estos dos minerales. Esta población combinatoria me sirvió para identificar los mecanismos antagónicos y sinérgicos que son esenciales para controlar la acumulación de Fe y Zn.Rice is staple crop for more than 3 billion people, since rice is poor source of iron (Fe) and zinc (Zn) world’s poorest people who depend on rice for their survival suffer from iron deficiency anaemia (IDA) and zinc deficiency (ZnD). Malnutrition is a significant challenge, particularly in the developing world where measures that are commonplace in industrialized countries (varied diet, fortification schemes, and dietary supplements) are largely absent. Biofortification of rice with Fe and Zn by genetic engineering is a promising strategy to increase Fe and Zn concentration. I established a combinatorial transgenic rice population by transformation with four genes involved in uptake, transport, accumulation and bioavailability of Fe and Zn, aiming to produce grains containing higher level of these two minerals. This combinatorial population helped to identify key antagonistic and synergistic mechanisms controlling Fe and Zn accumulation

The expression of heterologous Fe (III) phytosiderophore transporter HvYS1 in rice increases Fe uptake, translocation and seed loading and excludes heavy metals by selective Fe transport

10 Pags.- 1 Tabl.- 6 Figs. Copyrights, the Authors. Plant Biotechnology Journal is published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Many metal transporters in plants are promiscuous, accommodating multiple divalent cations including some which are toxic to humans. Previous attempts to increase the iron (Fe) and zinc (Zn) content of rice endosperm by overexpressing different metal transporters have therefore led unintentionally to the accumulation of copper (Cu), manganese (Mn) and cadmium (Cd). Unlike other metal transporters, barley Yellow Stripe 1 (HvYS1) is specific for Fe. We investigated the mechanistic basis of this preference by constitutively expressing HvYS1 in rice under the control of the maize ubiquitin1 promoter and comparing the mobilization and loading of different metals. Plants expressing HvYS1 showed modest increases in Fe uptake, root-to-shoot translocation, seed accumulation and endosperm loading, but without any change in the uptake and root-to-shoot translocation of Zn, Mn or Cu, confirming the selective transport of Fe. The concentrations of Zn and Mn in the endosperm did not differ significantly between the wild-type and HvYS1 lines, but the transgenic endosperm contained significantly lower concentrations of Cu. Furthermore, the transgenic lines showed a significantly reduced Cd uptake, root-to-shoot translocation and accumulation in the seeds. The underlying mechanism of metal uptake and translocation reflects the down-regulation of promiscuous endogenous metal transporters revealing an internal feedback mechanism that limits seed loading with Fe. This promotes the preferential mobilization and loading of Fe, therefore displacing Cu and Cd in the seed.We acknowledge support from the European Research Council IDEAS Advanced Grant Program (BIOFORCE) to P.C., and the Spanish Ministry of Economy and Competitivity (MINECO; projects AGL2013-42175-R, co-financed with FEDER) and the Aragón Government (Group A03) to J.A. R.B was supported by a PhD fellowship from the University of Lleida, Spain.Peer reviewe

Bacillus thuringiensis : a century of research, development and commercial applications

Bacillus thuringiensis (Bt) is a soil bacterium that forms spores during the stationary phase of its growth cycle. The spores contain crystals, predominantly comprising one or more Cry and/or Cyt proteins (also known as δ-endotoxins) that have potent and specific insecticidal activity. Different strains of Bt produce different types of toxin, each of which affects a narrow taxonomic group of insects. Therefore, Bt toxins have been used as topical pesticides to protect crops, and more recently the proteins have been expressed in transgenic plants to confer inherent pest resistance. Bt transgenic crops have been overwhelmingly successful and beneficial, leading to higher yields and reducing the use of chemical pesticides and fossil fuels. However, their deployment has attracted some criticism particularly with regard to the potential evolution of pest-resistant insect strains. Here, we review recent progress in the development of Bt technology and the countermeasures that have been introduced to prevent the evolution of resistant insect populations

The ratio of phytosiderophores nicotianamine to deoxymugenic acid controls metal homeostasis in rice

Main conclusion The ratio of nicotianamine to deoxymugenic acid controls tissue-specific metal homeostasis in rice and regulates metal delivery to the endosperm. Abstract The metal-chelating phytosiderophores nicotianamine (NA) and 2′deoxymugenic acid (DMA) are significant factors for the control of metal homeostasis in graminaceous plants. These compounds are thought to influence metal homeostasis, but their individual roles and the effect of altering the NA:DMA ratio are unknown. We purposely generated rice lines with high and low NA:DMA ratios (HND and LND lines, respectively). The HND lines accumulated more iron (Fe), zinc (Zn), manganese (Mn) and copper (Cu) in the endosperm through the mobilization of Fe, Zn and Mn from the seed husk to the endosperm. In contrast, Fe, Zn and Mn were mobilized to the husk in the LND lines, whereas Cu accumulated in the endosperm. Different groups of metals are, therefore, taken up, transported and sequestered in vegetative tissues in the HND and LND lines to achieve this metal distribution pattern in the seeds. We found that different sets of endogenous metal homeostasis genes were modulated in the HND and LND lines to achieve differences in metal homeostasis. Our findings demonstrate that the NA:DMA ratio is a key factor regulating metal homeostasis in graminaceous plants. These findings can help formulate refined strategies to improve nutrient composition and nutrient use efficiency in crop plants.We acknowledge support from the European Research Council IDEAS Advanced Grant Program (BIOFORCE) to P.C., Generalitat de Catalunya Grant 2017 SGR 828 to ABBU (BIO2014-54426-P) and the Spanish Ministry of Economy and Competitivity (MINECO; projects AGL2016-75226-R, co-financed with FEDER) and the Aragón Government (Group A09_17R) to J.A. R.B was supported by a PhD fellowship from the University of Lleida, Spain.Peer reviewe