Effects of three fertilizer application patterns on wheat sowed by machinery in slope cropland of Western Hubei, China.

Unscientific fertilization, unstable grain quality, and low profit are the key problems on wheat production in slope cropland of Western Hubei. To solve these problems, three optimized planting patterns (high nitrogen and potassium reduction, HNPR; medium nitrogen and potassium reductionm, MNPR; low nitrogen and potassium reduction, LNPR) were conducted during two consecutive years to assess their effects on wheat yield, quality, profit, and fertilizer use efficiency in Danjiangkou Reservoir area, a typical slope cropland region with wheat-maize rotation. The results showed that the application of chemical fertilizer significantly increased grain yield (GY) and wet gluten content (WGC) of wheat. Compared with the conventional planting pattern (CK), the partial factor productivity (PFPK) and agricultural fertilizer use efficiency (AFUEK) of potassium were significantly improved in the three optimized planting patterns. The dry matter amount (DMA), GY, and crude protein content (CPC) were the highest under HNPR, which increased by 9.4%, 19.4%, and 7.8% than CK, respectively. Such a result indicated that HNPR benefited wheat to exploit high yield potential. WGC and falling number (FN) were the highest under MNPR, and increased by 3.9%, and 9.3% than CK, respectively, which was suitable for high-efficiency production of medium-gluten wheat. PFPN, AFUEN, PFPK, AFUEK, and net profit were the highest under LNPR, which increased by 15.7%, 134.1%, 131.3%, 368.2%, and 37.3% than CK, respectively, while the CPC and WGC were decreased by 2.1% and 2.6% than CK, respectively, suggesting it was suitable for environment-friendly and simplified production of weak-gluten wheat production. Our results could provide a reference for wheat production in the slope cropland.

RBX1 prompts degradation of EXO1 to limit the homologous recombination pathway of DNA double-strand break repair in G1 phase.

End resection of DNA double-strand breaks (DSBs) to form 3' single-strand DNA (ssDNA) is critical to initiate the homologous recombination (HR) pathway of DSB repair. HR pathway is strictly limited in the G1-phase cells because of lack of homologous DNA as the templates. Exonuclease 1 (EXO1) is the key molecule responsible for 3' ssDNA formation of DSB end resection. We revealed that EXO1 is inactivated in G1-phase cells via ubiquitination-mediated degradation, resulting from an elevated expression level of RING-box protein 1 (RBX1) in G1 phase. The increased RBX1 significantly prompted the neddylation of Cullin1 and contributed to the G1 phase-specific degradation of EXO1. Knockdown of RBX1 remarkedly attenuated the degradation of EXO1 and increased the end resection and HR activity in γ-irradiated G1-phase cells, as demonstrated by the increased formation of RPA32, BrdU, and RAD51 foci. And EXO1 depletion mitigated DNA repair defects due to RBX1 reduction. Moreover, increased autophosphorylation of DNA-PKcs at S2056 was found to be responsible for the higher expression level of the RBX1 in the G1 phase. Inactivation of DNA-PKcs decreased RBX1 expression, and simultaneously increased EXO1 expression and DSB end resection in G1-phase cells. This study demonstrates a new mechanism for restraining the HR pathway of DNA DSB repair in G1 phase via RBX1-prompted inactivation of EXO1.

[Study on Characteristics of Terahertz Spectra of Organic Functional Groups].

Fourier transform infrared (FTIR) was exploited to measure terahertz (THz) spectra in the wave number range of 30-300 cm(-1) for saturated straight chain organic molecules at room temperature. The results reveal that different organic functional groups exhibit different THz spectral characteristics. The absorption peaks of vibration modes of organic crystal lattice locate in high frequency range of THz, while those of vibration modes of intermolecular hydrogen (H) bonds appear in low frequency range of THz. Moreover, a typical absorption peak of intermolecular H bonds caused by saturated straight-chain monohydric alcohol hydroxyl functional groups locates at 57 cm(-1), while a characteristic absorption peak of intermolecular hydrogen bonds caused by triacontanoic acid carboxyl functional groups appears at 74 cm(-1). The intermolecular H bonds not only result in that the THz absorbing abilities of triacontanol and triacontanoic acid are significantly stronger than that of triacontane, but also cause regular red-shift and blue-shift of the THz absorption peaks of triacontanoic acid, as compared with those of triacontanol. In addition, density functional theory (DFT) B3LYP/6-311G(d,p) basis set was employed to simulate the THz spectra of saturated straight-chain alkane, alkanol and acid, respectively. The simulation results indicate that for the organic molecules with stronger intermolecular H bonds, lower consistent degree of the THz spectrum simulated from monomer molecule with the THz spectrum experimentally measured will occur. Moreover, the simulation results of dimer structures agree well with the measured spectra as compared to those simulated from monomer molecule structures. The results presented in this work are of great significance not only to the study of the THz spectral characteristics of other organic functional groups, but also to the clarification of the vibration modes of organic molecules. Particularly, our results are also helpful for clarifying the THz response theory of organics, and for exploiting the applications of organic materials in THz devices.

Wheat-specific gene, ribosomal protein l21, used as the endogenous reference gene for qualitative and real-time quantitative polymerase chain reaction detection of transgenes.

Wheat-specific ribosomal protein L21 (RPL21) is an endogenous reference gene suitable for genetically modified (GM) wheat identification. This taxon-specific RPL21 sequence displayed high homogeneity in different wheat varieties. Southern blots revealed 1 or 3 copies, and sequence analyses showed one amplicon in common wheat. Combined analyses with sequences from common wheat (AABBDD) and three diploid ancestral species, Triticum urartu (AA), Aegilops speltoides (BB), and Aegilops tauschii (DD), demonstrated the presence of this amplicon in the AA genome. Using conventional qualitative polymerase chain reaction (PCR), the limit of detection was 2 copies of wheat haploid genome per reaction. In the quantitative real-time PCR assay, limits of detection and quantification were about 2 and 8 haploid genome copies, respectively, the latter of which is 2.5-4-fold lower than other reported wheat endogenous reference genes. Construct-specific PCR assays were developed using RPL21 as an endogenous reference gene, and as little as 0.5% of GM wheat contents containing Arabidopsis NPR1 were properly quantified.

[Characterization and simulation of far-infrared spectroscopy for saturated monohydric alcohols].

Fourier transform infrared-attenuated total reflection (FTIR-ATR) was employed to measure the far-infrared (FIR) spectra in wavenumbers of 30-300 cm(-1) for six kinds of saturated monohydric alcohols, namely: methanol, ethanol, propanol, isopropanol, butanol and isobutanol. Further analysis of the FIR spectra for these monohydric alcohols with similar chemical structures reveals that absorption peaks are observed obviously for these alcohols in the 30-150 cm(-1) band, whereas not obvious peaks are measured in the 150-300 cm(-1) band. Moreover, it was found that the monohydric alcohols with higher hydroxy concentration possess lower average FIR transmission. In addition, the average FIR transmissions of linear chain monohydric alcohols are higher than those of the branched chain ones. Furthermore, the density functional theory (DFT) B3LYP/6-311G(d,p) basis set was employed to simulate the structures optimization and to calculate the responding frequencies of the methanol monomer and polymer. Simulation result indicates that no absorption peaks are found in the 30-150 cm(-1) band for the methanol monomer molecule, whereas there are obvious absorption peaks for the methanol polymers in the same band. In addition, the simulated absorption peak positions for the methanol polymers are in agreement with those experimentally measured. Both results indicate that the absorption of the methanol in Terahertz (THz) is attributed to the collective vibrations of different kinds of polymer, and that the polymer for methanol is mainly trimmer. This paper not only provides a new way to investigate the responding frequencies of organic molecule in THz band, but also is helpful for the FTIR-ATR study of other organic molecules.

Trehalose 6-phosphate phosphatase is required for development, virulence and mycotoxin biosynthesis apart from trehalose biosynthesis in Fusarium graminearum.

Trehalose 6-phosphate synthase (TPS1) and trehalose 6-phosphate phosphatase (TPS2) are required for trehalose biosynthesis in yeast and filamentous fungi, including Fusarium graminearum. Three null mutants Δtps1, Δtps2 and Δtps1-Δtps2, each carrying either a single deletion of TPS1 or TPS2 or a double deletion of TPS1-TPS2, were generated from a toxigenic F. graminearum strain and were not able to synthesize trehalose. In contrast to its reported function in yeasts and filamentous fungi, TPS1 appeared dispensable for development and virulence. However, deletion of TPS2 abolished sporulation and sexual reproduction; it also altered cell polarity and ultrastructure of the cell wall in association with reduced chitin biosynthesis. The cell polarity alteration was exhibited as reduced apical growth and increased lateral growth and branching with increased hyphal and cell wall widths. Moreover, the TPS2-deficient strain displayed abnormal septum development and nucleus distribution in its conidia and vegetative hyphae. The Δtps2 mutant also had 62% lower mycelial growth on potato dextrose agar and 99% lower virulence on wheat compared with the wild-type. The Δtps1, Δtps2 and Δtps1-Δtps2 mutants synthesized over 3.08-, 7.09- and 2.47-fold less mycotoxins, respectively, on rice culture compared with the wild-type. Comparative transcriptome analysis revealed that the Δtps1, Δtps2 and Δtps1-Δtps2 mutants had 486, 1885 and 146 genotype-specific genes, respectively, with significantly changed expression profiles compared with the wild-type. Further dissection of this pathway will provide new insights into regulation of fungal development, virulence and trichothecene biosynthesis.