Rice grain with excessive cadmium (Cd) is a major source of dietary Cd intake and a serious threat to health for people who consume rice as a staple food. The development of elite rice cultivars with consistently low Cd content is challenging for conventional breeding approaches, and new strategies urgently need to be developed. Here, we report the development of new indica rice lines with low Cd accumulation and no transgenes by knocking out the metal transporter gene OsNramp5 using CRISPR/Cas9 system. Hydroponic culture showed that Cd concentrations in shoots and roots of osnramp5 mutants were dramatically decreased, resulting in rescue of impaired growth in high Cd condition. Cd-contaminated paddy field trials demonstrated that Cd concentration in osnramp5 grains was consistently less than 0.05 mg/kg, in contrast to high Cd concentrations from 0.33 mg/kg to 2.90 mg/kg in grains of Huazhan (the wild-type indica rice). In particular, the plant yield was not significantly affected in osnramp5 mutants. Furthermore, we developed promising hybrid rice lines with extremely low Cd content in grains. Our work supplies a practical approach to developing Cd pollution-safe indica rice cultivars that minimizes Cd contamination risk in grains.

1,4-Dihydropyridines have been photocatalytically oxidized to pyridines by platinum(II) terpyridyl complexes with the generation of hydrogen in homogeneous solution. The hydrogen production proceeds in quantitative yield and with great catalytic turnover.

The Northern Great Plains grasslands respond differently under various climatic conditions; however, there have been no detailed studies investigating the interannual variability in carbon exchange across the entire Northern Great Plains grassland ecosystem. We developed a piecewise regression model to integrate flux tower data with remotely sensed data and mapped the 8-d and 500-m net ecosystem exchange (NEE) for the years from 2000 to 2006. We studied the interannual variability of NEE, characterized the interannual NEE difference in climatically different years, and identified the drought impact on NEE. The results showed that NEE was highly variable in space and time across the 7 yr. Specifically, NEE was consistently low (235 to 32 g C ? m 22 ? yr 21) with an average annual NEE of 22 6 24 g C ? m 22 ? yr 21 and a cumulative flux of 215 g C ? m 22. The Northern Great Plains grassland was a weak source for carbon during 2000-2006 because of frequent droughts, which strongly affected the carbon balance, especially in the Western High Plains and Northwestern Great Plains. Comparison of the NEE map with a drought monitor map confirmed a substantial correlation between drought and carbon dynamics. If drought severity or frequency increases in the future, the Northern Great Plains grasslands may become an even greater carbon source. Resumen Los pastizales de las grandes planicies del norte responden de manera diferente bajo diversas condiciones climáticas; sin embargo, no ha habido ningún estudio en detalle que investigue la variabilidad entre añ os en el intercambio de carbono a través de todo el ecosistema de los pastizales de las grandes planicies del norte. Desarrollamos un modelo de regresión para integrar los datos de la torre de flujo con datos medidos de forma remota y establecer el intercambio de ecosistema neto (NEE) de 8 días y 500-m durante los años del 2000 al 2006. Estudiamos la variabilidad de NEE entre añ os caracterizando las diferencias climáticas entre añ os, e identificando el impacto de sequía en NEE. Los resultados mostraron que NEE fue demasiado variable en espacio y tiempo a través de los 7 añ os. Específicamente, NEE fue constantemente bajo (235 to 32 g C ? m 22 ? yr 21) con un promedio anual NEE de 22 6 24 g C ? m 22 ? yr 21 y una variación acumulada de 215 g C ? m 22. Los pastizales de las planicies del norte fueron una fuente baja de carbono durante los añ os 2000-2006 debido a las sequías frecuentes, que afectan considerablemente el equilibrio de carbono, especialmente en la parte occidental de las altas planicies y en el noroeste de las grandes planicies. Comparación del registro de NEE con un mapa de monitoreo de la sequía confirmó una sustancial correlación entre la sequía y la dinámica del carbono. Si la gravedad o frecuencia de la sequía es aumenta en el futuro, los pastizales de las grandes planicies del norte pueden convertirse en una fuente de carbono aún mayor.