Proteomic Profiling for Metabolic Pathways Involved in Interactive Effects of Elevated Carbon Dioxide and Nitrogen on Leaf Growth in a Perennial Grass Species

CO2 enhances low-nitrogen adaption by promoting amino acid metabolism in Brassica napus

Increasing concentrations of atmospheric CO2 are driving climate change and negatively impacting the carbon-nitrogen (C/N) balance in crops, which in turn alters fertilizer use efficiency. In this study, Brassica napus was cultivated under different CO2 and NO3--N concentrations to study the impact of C/N ratio on plant growth. Elevated CO2 enhanced biomass and nitrogen assimilation efficiency under low NO3--N conditions, indicating an adaptation by Brassica napus. Transcriptome and metabolome analyses revealed that elevated CO2 promoted amino acid catabolism under low NO3--N conditions. This study provides new insights into how Brassica napus adapts to environmental change.

Effect of the Interaction between Elevated Carbon Dioxide and Iron Limitation on Proteomic Profiling of Soybean

Elevated atmospheric CO2 (eCO2) and iron (Fe) availability are important factors affecting plant growth that may impact the proteomic profile of crop plants. In this study, soybean plants treated under Fe-limited (0.5 mM) and Fe-sufficient (20 mM) conditions were grown at ambient (400 μmol mol−1) and eCO2 (800 μmol mol−1) in hydroponic solutions. Elevated CO2 increased biomass from 2.14 to 3.14 g plant−1 and from 1.18 to 2.91 g plant−1 under Fe-sufficient and Fe-limited conditions, respectively, but did not affect leaf photosynthesis. Sugar concentration increased from 10.92 to 26.17 μmol g FW−1 in roots of Fe-sufficient plants and from 8.75 to 19.89 μmol g FW−1 of Fe-limited plants after exposure to eCO2. In leaves, sugar concentration increased from 33.62 to 52.22 μmol g FW−1 and from 34.80 to 46.70 μmol g FW−1 in Fe-sufficient and Fe-limited conditions, respectively, under eCO2. However, Fe-limitation decreases photosynthesis and biomass. Pathway enrichment analysis showed that cell wall organization, glutathione metabolism, photosynthesis, stress-related proteins, and biosynthesis of secondary compounds changed in root tissues to cope with Fe-stress. Moreover, under eCO2, at sufficient or limited Fe supply, it was shown an increase in the abundance of proteins involved in glycolysis, starch and sucrose metabolism, biosynthesis of plant hormones gibberellins, and decreased levels of protein biosynthesis. Our results revealed that proteins and metabolic pathways related to Fe-limitation changed the effects of eCO2 and negatively impacted soybean production.

Suppression of GhGLU19 encoding β-1,3-glucanase promotes seed germination in cotton

BACKGROUND

In eudicots, germination begins with water uptake by the quiescent dry seed and is greatly related to the permeability of micropyle enriched callose layers. Once imbibition starts, seeds undergo a cascade of physiological, biochemical, and molecular events to initiate cellular activities. However, the effects of callose on water uptake and following seed metabolic events during germination are largely unknown. Cotton (Gossypium hirsutum) is a eudicot plant with natural fiber and edible oil production for humans. Here, we addressed this question by examining the role of GhGLU19, a gene encoding β-1,3-glucanase, in cotton seed germination.

RESULTS

GhGLU19 belongs to subfamily B and was expressed predominately in imbibed seeds and early seedlings. Compared to wild type, GhGLU19-suppressing and GhGLU19-overexpressing transgenic cotton lines showed the higher and lower seed germination percentage, respectively. Callose was enriched more at inner integument (ii) than that in embryo and seed coat in cotton seeds. In GhGLU19-suppressing lines, callose at ii of cotton seeds was greatly increased and brought about a prolonged water uptake process during imbibition. Both proteomic and transcriptomic analysis revealed that contrary to GhGLU19-overexpressing lines, the glycolysis and pyruvate metabolism was decreased, and abscisic acid (ABA) biosynthesis related genes were downregulated in imbibed seeds of GhGLU19-suppressing lines. Also, endogenous ABA was significantly decreased in GhGLU19-suppressing line while increased in GhGLU19-overexpressing line.

CONCLUSIONS

Our results demonstrate that suppression of GhGLU19 improves cotton seed germination via accumulating callose of inner integument, modulating glycolysis and pyruvate metabolism, and decreasing ABA biosynthesis. This study provides a potential way for improving germination percentage in cotton seed production, and other eudicot crops.

Reallocation of Soluble Sugars and IAA Regulation in Association with Enhanced Stolon Growth by Elevated CO2 in Creeping Bentgrass

Extensive stolon development and growth are superior traits for rapid establishment as well as post-stress regeneration in stoloniferous grass species. Despite the importance of those stoloniferous traits, the regulation mechanisms of stolon growth and development are largely unknown. The objectives of this research were to elucidate the effects of the reallocation of soluble sugars for energy reserves and endogenous hormone levels for cell differentiation and regeneration in regulating stolon growth of a perennial turfgrass species, creeping bentgrass (Agrostis stolonifera L.). Plants were grown in growth chambers with two CO₂ concentrations: ambient CO₂ concentration (400 ± 10 µmol mol⁻¹) and elevated CO₂ concentration (800 ± 10 µmol mol⁻¹). Elevated CO₂ enhanced stolon growth through increasing stolon internode number and internode length in creeping bentgrass, as manifested by the longer total stolon length and greater shoot biomass. The content of glucose, sucrose, and fructose as well as endogenous IAA were accumulated in stolon nodes and internodes but not in leaves or roots under elevated CO₂ concentration. These results illustrated that the production and reallocation of soluble sugars to stolons as well as the increased level of IAA in stolon nodes and internodes could contribute to the enhancement of stolon growth under elevated CO₂ in creeping bentgrass.

Hepatic Proteomic Changes and Sirt1/AMPK Signaling Activation by Oxymatrine Treatment in Rats With Non-alcoholic Steatosis

Background

Currently, active ingredients of herbal extracts that can suppress lipid accumulation in the liver have been considered a potential treatment option for non-alcoholic fatty liver disease.

Methods

Steatosis rat model was created by high fat and high sucrose diet feeding and treated with oxymatrine (OMT). Serum biochemical parameters, liver histology and lipid profiles were examined. Hepatic differentially expressed proteins (DEPs) which were significantly changed by OMT treatment were identified by iTRAQ analysis. The expressions of representative DEPs, Sirt1 and AMPKα were evaluated by western blotting.

Results

OMT significantly reduced the body weight and liver weight of steatosis animals, decreased the serum levels of triglyceride and total cholesterol as well as the hepatic triglyceride and free fatty acid levels, and effectively alleviated fatty degeneration in the liver. A list of OMT-related DEPs have been screened and evaluated by bioinformatics analysis. OMT significantly decreased the expressions of L-FABP, Plin2, FASN and SCD1 and increased Sirt1 expression and AMPKα phosphorylation in the liver of rats with steatosis.

Conclusion

The present study has confirmed the significant efficacy of OMT for improving steatosis and revealed hepatic proteomic changes and Sirt1/AMPK signaling activation by OMT treatment in rats with steatosis.