Changes in Whole-Plant Metabolism During Grain-Filling Stage in Sorghum Bicolor L. (Moench) Grown Under Elevated Co2 and Drought

Abstract

Projections indicate an elevation of the atmospheric CO 2 concentration ([CO 2 ]) concomitant with an intensification of drought for this century, increasing the challenges to food security. On the one hand, drought is a main environmental factor responsible for decreasing crop productivity and grain quality, especially when occurring during the grain-filling stage. On the other hand, elevated [CO 2 ] is predicted to mitigate some of the negative effects of drought. Sorghum (Sorghum bicolor) is a C 4 grass that has important economical and nutritional values in many parts of the world. Although the impact of elevated [CO 2 ] and drought in photosynthesis and growth has been well documented for sorghum, the effects of the combination of these two environmental factors on plant metabolism have yet to be determined. To address this question, sorghum plants (cv BRS 330) were grown and monitored at ambient (400 mmol mol 21 ) or elevated (800 mmol mol 21 ) [CO 2 ] for 120 d and subjected to drought during the grainfilling stage. Leaf photosynthesis, respiration, and stomatal conductance were measured at 90 and 120 d after planting, and plant organs (leaves, culm, roots, prop roots, and grains) were harvested. Finally, biochemical composition and intracellular metabolites were assessed for each organ. As expected, elevated [CO 2 ] reduced the stomatal conductance, which preserved soil moisture and plant fitness under drought. Interestingly, the whole-plant metabolism was adjusted and protein content in grains was improved by 60% in sorghum grown under elevated [CO 2 ].Global food demand is projected to increase up to 110% by the middle of this century (Tilman et al., 2011; Alexandratos and Bruinsma, 2012), particularly due to a rise in world population that is likely to plateau at about 9 billion people (Godfray et al., 2010 (NOAA, 2015). According to the A2 emission scenario from the U.S. Environmental Protection Agency, in the absence of explicit climate change policy, atmospheric CO 2 concentrations will reach 800 mmol mol 21 by the end of this century. The increasing atmospheric [CO 2 ] is resulting in global climate changes, such as reduction in water availability and elevation in temperature. These factors are expected to heavily influence food production in the next years (Godfray and Garnett, 2014;Magrin et al., 2014). Sorghum (Sorghum bicolor) is a C 4 grass, considered a staple food grain for millions of the poorest and most food-insecure people in the semiarid tropics of Africa, Asia, and Central America, serving as an important source of energy, proteins, vitamins, and minerals (Taylor et al., 2006). Moreover, this crop is used for animal feed and as industrial raw material in developed countries such as the United States, which is the main world producer (FAO, 2015). With a fully sequenced genome (Paterson et al., 2009) and over 45,000 accessions representing a large geographic and genetic diversity, sorghum is a good model system in which to study the impact of global climate changes in C 4 grasses. ...

Genotypic covariations of traits underlying sorghum stem biomass production and quality and their regulations by water availability: Insight from studies at organ and tissue levels

“…The role of soluble sugar accumulation contributing, in water deficit conditions, to cell osmoregulation and tissue turgor maintenance was already reported (de Souza, Cocuron, Garcia, Alonso, & Buckeridge, 2015). The role of soluble sugar accumulation contributing, in water deficit conditions, to cell osmoregulation and tissue turgor maintenance was already reported (de Souza, Cocuron, Garcia, Alonso, & Buckeridge, 2015).…”

A Combined Metabolomics and Fluxomics Analysis Identifies Steps Limiting Oil Synthesis in Maize Embryos

“…Metabolomics quantify key intermediary compounds involved in primary pathways De Souza et al, 2015;Tsogtbaatar et al, 2015). Alex and LH59 kernels were harvested at 15, 22, and 28 DAP, the embryos were dissected, and their intracellular metabolite were extracted in boiling water as previously described (Alonso et al, 2010b;.…”

BioNetStat: uma ferramenta para análise diferencial de redes biológicas

“…Sabe-se que o metabolismo e enchimento do grão são afetados pelo metabolismo de todos os outros órgãos da planta(de Souza et al 2015). Entretanto, os trabalhos realizados com metabolismo vegetal, em geral, são focados nas respostas de apenas um único órgão(de Souza et al 2015). Sicher e Barnaby (2012), por exemplo, estudaram o metabolismo da folha de milho sem considerar o efeito da resposta do colmo e da raiz aos tratamentos.…”

“…Sicher e Barnaby (2012), por exemplo, estudaram o metabolismo da folha de milho sem considerar o efeito da resposta do colmo e da raiz aos tratamentos. Por esse motivo, um dos objetivos do trabalhode De Souza et al (2015) foi (i) comparar as diferenças nos perfis metabólicos de cinco órgãos de Sorgo (Folha, Colmo, Raiz, Raiz escora e Grãos). O Sorgo (Sorghum bicolor) é uma espécie muito usada como matéria prima da ração para o gado bovino em países desenvolvidos, como os EUA.…”

“…O Sorgo (Sorghum bicolor) é uma espécie muito usada como matéria prima da ração para o gado bovino em países desenvolvidos, como os EUA. Por ter o genoma completamente sequenciado e ser uma espécie com diversidade genética e geográfica, o sorgo é um bom modelo em gramíneas de metabolismo fotossintético C 4(de Souza et al 2015).Os dados produzidos por De Souza et al (2015) estão descritos na seção 2.3.2. Ao construir as redes de metabolismo de sorgo retiramos os metabólitos que não foram identificados em pelo menos uma das unidades amostrais, restando 73 dos 79 metabólitos originais.…”