Metabolomics Reveals Distinct Carbon and Nitrogen Metabolic Responses to Magnesium Deficiency in Leaves and Roots of Soybean [Glycine max (Linn.) Merr.]

Magnesium (Mg) deficiency, a widespread yet overlooked problem in agriculture, has been reported to retard plant growth and development, through affecting key metabolic pathways. However, the metabolic responses of plant to Mg deficiency is still not fully understood. Here we report a metabolomic study to evaluate the metabolic responses to Mg deficiency in soybean leaves and roots. Hydroponic grown soybean were exposed to Mg starvation for 4 and 8 days, respectively. Metabolic changes in the first mature trifoliolate leaves and roots were quantified by conducting GC-TOF-MS based metabolomic analysis. Principal component analysis (PCA) showed that Mg deficient plants became distinguishable from controls at 4 days after stress (DAS) at metabolic level, and were clearly discriminated at 8 DAS. Mg deficiency could cause large metabolite alterations on carbon and nitrogen metabolism. At 8 DAS, carbon allocation from shoot to root is decreased by Mg deficiency. Remarkably, most amino acids (such as phenylalanine, asparagine, leucine, isoleucine, glycine, glutamine, and serine) showed pronounced accumulation in the leaves, while most organic acids (including pyruvic acid, citric acid, 2-keto-glutaric acid, succinic acid, fumaric acid, and malic acid) were significantly decreased in the roots. Our study shows that the carbon and nitrogen metabolic responses are distinct in leaves and roots under Mg deficiency

Mechanism of Synergy between Piceatannol and Ciprofloxacin against <i>Staphylococcus aureus</i>

Piceatannol (PIC) is a natural stilbene extracted from grape skins that exhibits biological activities such as antibacterial, antitumor, and antioxidant activities. The present study was carried out to further investigate the effect of PIC on the antibacterial activity of different antibiotics and to reveal the antibacterial mechanism of PIC. We found that PIC had an inhibitory effect against Staphylococcus aureus (S. aureus); its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 128 μg/mL and 256 μg/ mL, respectively. Additionally, we measured the fractional inhibitory concentration (FIC) of PIC combined with antibiotics via the checkerboard method. The results showed that when PIC and ciprofloxacin (CIP) were combined, they displayed a synergistic effect against S. aureus. Moreover, this synergistic effect was verified by time–kill assays. Further, the results of the membrane permeability assay and proton motive force assay revealed that PIC could enhance the sensitivity of S. aureus to CIP by dissipating the bacterial proton motive force (PMF), particularly the ∆ψ component, rather than increasing membrane permeability. PIC also inhibited bacterial adenosine triphosphate (ATP) synthesis and was less likely to induce bacterial resistance but exhibited slight hemolytic activity on mammalian erythrocytes. In summary, the combination of PIC and CIP is expected to become a new drug combination to combat S. aureus

Multiplex genome editing targeting soybean with ultra-low anti-nutritive oligosaccharides

Soybean is the primary source of plant protein for humans. Owing to the indigestibility of the raffinose family of oligosaccharides (RFO), raffinose and stachyose are considered anti-nutritive factors in soybean seeds. Low-RFO soybean cultivars are generated by mutagenesis of RFO biosynthesis genes, but the carbohydrate profiles invite further modification to lower RFOs. This study employed a pooled multiplex genome editing approach to target four seed-specifically expressed genes mediating RFO biosynthesis, encoding three raffinose synthases (RS2, RS3, and RS4) and one stachyose synthase. In T1 progeny, rs2/rs3 and rs4/sts homozygous double mutants and a rs2/rs3/rs4/sts quadruple mutant (rfo-4m) were characterized. The rs2/rs3 mutant showed reduced raffinose and stachyose contents, but the rs4/sts mutant showed only reduced stachyose in seeds. The RFO contents in the rfo-4m mutant were almost eliminated. Metabolomic analysis showed that the mutation of four RFO biosynthesis genes led to a shift of metabolic profile in the seeds, including the accumulation of several oligosaccharides-related metabolites. These mutants could contribute to precision breeding of soybean cultivars for soy food production

Ensiling characteristics, in vitro rumen fermentation profile, methane emission and archaeal and protozoal community of silage prepared with alfalfa, sainfoin and their mixture

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NTIRE 2019 Challenge on Real Image Super-Resolution: Methods and Results

This paper reviewed the 3rd NTIRE challenge on single-image super-resolution (restoration of rich details in a low-resolution image) with a focus on proposed solutions and results. The challenge had 1 track, which was aimed at the real-world single image super-resolution problem with an unknown scaling factor. Participants were mapping low-resolution images captured by a DSLR camera with a shorter focal length to their high-resolution images captured at a longer focal length. With this challenge, we in-troduced a novel real-world super-resolution dataset (Re-alSR). The track had 403 registered participants, and 36 teams competed in the final testing phase. They gauge the state-of-the-art in real-world single image super-resolution