Selección de líneas avanzadas de arroz (Oryza sp.) como alternativa para la gestión sostenible de suelos degradados por salinidad

La investigación se centra en las líneas avanzadas desarrolladas a través de cruces interespecíficos entre Oryza sativa L. ssp. japonica x Oryza rufipogon G., y la línea tipo japónica, cuya tolerancia a las sales bajo condiciones de invernadero y campo se sometieron a evaluación. En la primera fase en invernadero, se sembraron 24 líneas avanzadas de arroz F5, cinco líneas parentales y un cultivar comercial SFL-011 (control) en medio líquido con una concentración de 7,0 dS/m CE salinizado con NaCl y control con 0,2.dS/m CE de agua de riego. En la segunda fase en condiciones de campo se evaluaron líneas de arroz F6 en suelos salinos con 7.44 dS/m CE. Se midieron variables agronómicas y de rendimiento. En condiciones de invernadero se destacaron seis líneas: Puyón/JP003 P11-106716, Puyón/JP002 P8-30552, Puyón/JP003 P11-103115, Puyón/JP002 P8-294930, JP002/JP001 P × P 5P 1322 y JP001/JP003 P1 × 11P 413, con mayor tolerancia que el control en cuanto a vigor de planta, panículas por planta, granos por panícula, peso de 1000 granos y rendimiento (g/planta). En condiciones de campo, dos líneas, Puyón/JP003 P11-106716 y Puyón/JP003 P11-103115, se destacaron por tener mejores resultados agronómicos en cultivares y rendimiento. Los resultados mostraron la importancia del uso de cruces interespecíficos entre O. Sativa ssp. japonica x O. rufipogon, y la línea tipo japónica para mejorar la tolerancia a la salinidad del arroz y garantizar altos rendimientos potenciales en suelos salinizados; de ahí la importancia del cruce en términos de rendimientos agrícolas.

Formation of carboxylated and decarboxylated betalains in ripening grains of Chenopodium quinoa by a dual dioxygenase

Chenopodium quinoa (quinoa) is a pseudo-cereal that forms part of the cultural heritage of Andean countries, and its grains have high nutritional value and potential health benefits. Betalains are nitrogenous water-soluble pigments and bioactive molecules that contribute to these health-promoting properties. Betalains are restricted to plants of the order Caryophyllales, to which quinoa belongs. A new family of betalains has been discovered in the form of unconventional decarboxylated pigments. Here, we show that these pigments accumulate in ripening quinoa grains of fluorescent nature, and are putatively based on a dopamine-cleaving activity. This study describes for the first time the purification and molecular and functional characterization of a 4,5-dopamine extradiol dioxygenase enzyme from plants. It is a monomeric protein with a molecular mass of 34.5 kDa characterized by chromatography, electrophoresis, and time-of-flight mass spectrometry. We demonstrate that this key enzyme has a dual function in a square-shaped biosynthetic pathway towards the formation of both carboxylated and decarboxylated pigments. Enzyme kinetic properties are characterized for the production of 6-decarboxy-betalamic acid and 3,4-dihydroxy-l-phenylalanine-derived betalamic acid, the two structural units of plant pigment in nature. The profile of multiple betalains present in quinoa grains has been reproduced in one-pot bioreactors containing the novel enzyme and two competing substrates.

A dopamine-based biosynthetic pathway produces decarboxylated betalains in Chenopodium quinoa

Betalains are the nitrogenous pigments that replace anthocyanins in the plant order Caryophyllales. Here, we describe unconventional decarboxylated betalains in quinoa (Chenopodium quinoa) grains. Decarboxylated betalains are derived from a previously unconsidered activity of the 4,5-DOPA-extradiol-dioxygenase enzyme (DODA), which has been identified as the key enzymatic step in the established biosynthetic pathway of betalains. Here, dopamine is fully characterized as an alternative substrate of the DODA enzyme able to yield an intermediate and structural unit of plant pigments: 6-decarboxy-betalamic acid, which is proposed and described. To characterize this activity, quinoa grains of different colors were analyzed in depth by chromatography, time-of-flight mass spectrometry, and reactions were performed in enzymatic assays and bioreactors. The enzymatic-chemical scheme proposed leads to an uncharacterized family of 6-decarboxylated betalains produced by a hitherto unknown enzymatic activity. All intermediate compounds as well as the final products of the dopamine-based biosynthetic pathway of pigments have been unambiguously determined and the reactions have been characterized from the enzymatic and functional perspectives. Results evidence a palette of molecules in quinoa grains of physiological relevance and which explain minor betalains described in plants of the Caryophyllales order. An entire family of betalains is anticipated.

Development of Betalain Producing Callus Lines from Colored Quinoa Varieties (Chenopodium quinoa Willd)

Betalains are water-soluble plant pigments of hydrophilic nature with promising bioactive potential. Among the scarce edible sources of betalains is the grain crop quinoa (Chenopodium quinoa Willd), with violet, red, and yellow grains being colored by these pigments. In this work, callus cultures have been developed from differently colored plant varieties. Stable callus lines exhibited color and pigment production when maintained on Murashige and Skoog medium supplemented with the plant growth regulators 6-benzylaminopurine (8.88 μM) and 2,4-dichlorophenoxyacetic acid (6.79 μM) with a reduction of the nitrogen source to 5.91 mM. Pigment analysis by HPLC-DAD and ESI-MS/MS fully describes the content of individual pigments in the cell lines and allows the first report on the pigments present in quinoa seedlings. Phyllocactin and vulgaxanthin I are described as novel pigments in the species and show the potential of C. quinoa culture lines in the production of compounds of nutritional value.