RESUMO
Cereal crops are significant contributors to global diets. As climate change disrupts weather patterns and wreaks havoc on crops, the need for generating stress-resilient, high-yielding varieties is more urgent than ever. One extremely promising avenue in this regard is to exploit the tremendous genetic diversity expressed by the wild ancestors of current day crop species. These crop wild relatives thrive in a range of environments and accordingly often harbor an array of traits that allow them to do so. The identification and introgression of these traits into our staple cereal crops can lessen yield losses in stressful environments. In the last decades, a surge in extreme drought and flooding events have severely impacted cereal crop production. Climate models predict a persistence of this trend, thus reinforcing the need for research on water stress resilience. Here we review: (i) how water stress (drought and flooding) impacts crop performance; and (ii) how identification of tolerance traits and mechanisms from wild relatives of the main cereal crops, that is, rice, maize, wheat, and barley, can lead to improved survival and sustained yields in these crops under water stress conditions.
Assuntos
Desidratação , Grão Comestível , Mudança Climática , Produtos Agrícolas/genética , Grão Comestível/genética , Zea maysRESUMO
Sugar supply is a key component of hypoxia tolerance and acclimation in plants. However, a striking gap remains in our understanding of mechanisms governing sugar impacts on low-oxygen responses. Here, we used a maize (Zea mays) root-tip system for precise control of sugar and oxygen levels. We compared responses to oxygen (21 and 0.2%) in the presence of abundant versus limited glucose supplies (2.0 and 0.2%). Low-oxygen reconfigured the transcriptome with glucose deprivation enhancing the speed and magnitude of gene induction for core anaerobic proteins (ANPs). Sugar supply also altered profiles of hypoxia-responsive genes carrying G4 motifs (sources of regulatory quadruplex structures), revealing a fast, sugar-independent class followed more slowly by feast-or-famine-regulated G4 genes. Metabolite analysis showed that endogenous sugar levels were maintained by exogenous glucose under aerobic conditions and demonstrated a prominent capacity for sucrose re-synthesis that was undetectable under hypoxia. Glucose abundance had distinctive impacts on co-expression networks associated with ANPs, altering network partners and aiding persistence of interacting networks under prolonged hypoxia. Among the ANP networks, two highly interconnected clusters of genes formed around Pyruvate decarboxylase 3 and Glyceraldehyde-3-phosphate dehydrogenase 4. Genes in these clusters shared a small set of cis-regulatory elements, two of which typified glucose induction. Collective results demonstrate specific, previously unrecognized roles of sugars in low-oxygen responses, extending from accelerated onset of initial adaptive phases by starvation stress to maintenance and modulation of co-expression relationships by carbohydrate availability.
Assuntos
Oxigênio/metabolismo , Proteínas de Plantas/genética , Açúcares/metabolismo , Transcriptoma , Zea mays/metabolismo , Anaerobiose , Glucose/metabolismo , Gliceraldeído-3-Fosfato Desidrogenases/genética , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Piruvato Descarboxilase/genética , Estresse Fisiológico , Zea mays/genéticaRESUMO
En el presente estudio se evaluó el crecimiento y la eficiencia fotosintética de Ludwigia decurrens (Onagraceae), a partir de la estimación de la fluorescencia de la clorofila bajo diferentes concentraciones de nitrógeno (0 mg/L, 465 mg/L y 930 mg/L) en condiciones de laboratorio. Como parámetros de crecimiento se utilizaron la longitud total del tallo y el área foliar. Durante el periodo de estudio se observó un incremento en el crecimiento y la eficiencia quántica con el aumento en la concentración de nitrógeno. Sin embargo, no se presentaron diferencias significativas (p Ludwigia decurrens crece en ambientes relativamente altos de nitrógeno.
Growth parameters and quantum efficiency measurements of the photosynthesis were evaluated on the emergent macrophyte Ludwigia decurrens under different concentrations of nitrogen (0 mg/L, 465 mg/L y 930 mg/L). Growth was determined as measurements of total length and leaf area, and the emission of chlorophyll fluorescence was used as a measure of real quantum efficiency of the photosystem II. During the study period, a general tendency of increase of growth parameters and quantum efficiency with increase of nitrogen supply was noted. However, there was no significant difference (pLudwigia decurrens can grow on enriched nitrogen environments.