Development of predictive models for total phenolics and free p-coumaric acid contents in barley grain by near-infrared spectroscopy.

Barley grains are rich in phenolic compounds, which are associated with reduced risk of chronic diseases. Development of barley cultivars with high phenolic acid content has become one of the main objectives in breeding programs. A rapid and accurate method for measuring phenolic compounds would be helpful for crop breeding. We developed predictive models for both total phenolics (TPC) and p-coumaric acid (PA), based on near-infrared spectroscopy (NIRS) analysis. Regressions of partial least squares (PLS) and least squares support vector machine (LS-SVM) were compared for improving the models, and Monte Carlo-Uninformative Variable Elimination (MC-UVE) was applied to select informative wavelengths. The optimal calibration models generated high coefficients of correlation (rpre) and ratio performance deviation (RPD) for TPC and PA. These results indicated the models are suitable for rapid determination of phenolic compounds in barley grains.

Metabolic analysis of two contrasting wild barley genotypes grown hydroponically reveals adaptive strategies in response to low nitrogen stress.

Nitrogen (N) is an essential macronutrient for plants. The increasingly severe environmental problems caused by N fertilizer application urge alleviation of N fertilizer dependence in crop production. In previous studies, we identified the Tibetan wild barley accessions with high tolerance to low nitrogen (LN). In this study, metabolic analysis was done on two wild genotypes (XZ149, tolerant and XZ56, sensitive) to understand the mechanism of LN tolerance, using a hydroponic experiment. Leaf and root samples were taken at seven time points within 18 d after LN treatment, respectively. XZ149 was much less affected by low N stress than XZ56 in plant biomass. A total of 51 differentially accumulated metabolites were identified between LN and normal N treated plants. LN stress induced tissue-specific changes in carbon and nitrogen partitioning, and XZ149 had a pattern of energy-saving amino acids accumulation and carbon distribution in favor of root growth that contribute to its higher LN tolerance. Moreover, XZ149 is highly capable of producing energy and maintaining the redox homeostasis under LN stress. The current results revealed the mechanisms underlying the wild barley in high LN tolerance and provided the valuable references for developing barley cultivars with LN tolerance.

Manganese(III) acetate promoted regioselective phosphonation of heteroaryl compounds.

[Structure: see text] A new method for direct phosphonation of thiazoles, furans, and pyrroles is introduced. Reactions of the heteroaryl compounds with dimethyl or diethyl phosphites and Mn(OAc)(3).2H2O under mild conditions give phosphonated products in high yield and good regioselectivity.