Transgenic approaches for improving use efficiency of nitrogen, phosphorus and potassium in crops

The success of the Green Revolution largely relies on fertilizers, and a new Green Revolution is very much needed to use fertilizers more economically and efficiently, as well as with more environmental responsibility. The use efficiency of nitrogen, phosphorus, and potassium is controlled by complex gene networks that co-ordinate uptake, re-distribution, assimilation, and storage of these nutrients. Great progress has been made in breeding nutrient-efficient crops by molecularly engineering root traits desirable for efficient acquisition of nutrients from soil, transporters for uptake, redistribution and homeostasis of nutrients, and enzymes for efficient assimilation. Regulatory and transcription factors modulating these processes are also valuable in breeding crops with improved nutrient use efficiency and yield performance.

Hitchhiking Effect Mapping: A New Approach for Discovering Agronomic Important Genes

Besides the natural selection, the crops cultivated today have experienced two episodes of strong artificial selection, domestic and modern breeding. Domestication led to giant genetic structure differentiation between cultivars and their wild species, while modern breeding made further genetic structure differentiation between the modern varieties and the landraces. In a population, diversity of the loci under strong selection is significantly lower than that of other loci. At the same time, diversity in the genomic regions flanking these selected loci also declines in the process of selection. This phenomenon is called hitchhiking effects or selection sweep in genetics. Genomic regions with selection sweep （haplotype block） could be detected after draft genome scanning （genome typing） with molecular markers in a number of released varieties or natural populations. Marker/trait association analysis in these regions would detect the loci （or QTLs） even the favored alleles （genes） in breeding or natural adaptation. Fine scanning of these genomic regions would help to determine the sizes of haplotype blocks and to discover the key genes, thereby providing very valuable information for isolation of the key genes and molecular design of new varieties. Establishment of high density genetic linkage maps in the major crops and availability of high throughput genotyping platform make it possible to discover agronomic important genes through marker/trait association analysis. On the basis of available publications, we give a brief introduction of the hitchhiking effect mapping approach in this paper using plant height, 1 000-grain weight, and phosphorus-deficiency tolerance as examples in wheat.

Characterization of Quantitative Trait Loci for Grain Minerals in Hexaploid Wheat (Triticum aestivum L.)

Wheat is an important source of essential minerals for human body. Breeding wheat with high grain mineral concentration thus benefits human health. The objective of present study was to identify quantitative trait loci （QTLs） controlling grain mineral concentration and to evaluate the relation between nitrogen （N） and other essential minerals in winter wheat. Wheat grains were harvested from field experiment which conducted in China and analyzed for this purpose. Forty-three QTLs controlling grain mineral concentration and nitrogen-related traits were detected by using a double haploid （DH） population derived from winter wheat varieties Hanxuan 10 and Lumai 14. Chromosomes 4D and 5A might be very important in controlling mineral status in wheat grains. Significant positive correlations were found between grain nitrogen concentration （GNC） and nutrients Fe, Mn, Cu, Mg concentrations （FeGC, MnGC, CuGC, MgGC）. Flag leafN concentration at anthesis （FLNC） significantly and positively correlated with GNC, FeGC, MnGC, and CuGC. The study extended our knowledge on minerals in wheat grains and suggested which interactions between minerals should be considered in future breeding program.

一个含1-甲基咪唑的环状梯型核[V10O20]及特别的电子构型的十核钒氧簇合物的合成、结构及理论计算（英文）

合成并表征了一个稀少的含1-甲基咪唑(L)及混合价的[V14O36F2L2]6-阴离子化合物的晶体结构。该阴离子是由一个环状的[V10O20]梯和2对架于梯上的VO5F及VO3L碎片组成。DFT及键价计算表明架着的VO5F碎片中V是+4价,其余V均为+5价。前线分子轨道分析表明:[V14O36F2L2]^6-阴离子架着的VO5F碎片中,V的d轨道是化学上活性的;而其2e氧化型[V14O36F2L2]^4-阴离子的VO3L碎片中,端基V=O(d-p)π轨道是化学上活性的。从[V14O36F2L2]^4-变成[V14O36F2L2]6-阴离子,2e的引入,导致了[V10O20]梯更加稳固,但架于其上的VO5F及VO3L碎片却越来越活泼(不稳定),并且能隙大幅降低(从1.59eV变为0.53eV)。

白光LED用YAG:Ce3+荧光粉的合成及发光性能研究

采用高温固相法合成YAG:Ce^3+黄色荧光粉材料,用正交分析法研究了煅烧时间、煅烧温度和Ce^3+浓度对荧光粉发光强度的影响。在煅烧温度为1600℃,Ce^3+浓度为0.12mol,煅烧时间为4h的条件下,得到的荧光粉发光性能最佳。硼酸作为助熔剂,当其浓度含量为1.2wt%,荧光粉的发光强度增大约40%。YAG:Ce^3+荧光粉的激发峰呈现双峰特征,其中最大激发峰位于467nm;最大发射峰位于529nm处,因此,YAG:Ce^3+黄色荧光粉可以与蓝光GaN芯片匹配制备双基色LED。

Wheat PROTON GRADIENT REGULATION 5 is Involved in Tolerance to Photoinhibition

Wheat （Triticum aestivum L.） often experiences photoinhibition due to strong light during the grain filling stage. As such, increasing the tolerance of wheat to photoinhibition is very desirable in breeding efforts focused on increasing grain yields. Previous reports have suggested that PROTON GRADIENT REGULATION 5 （PGR5） plays a central role in the generation of a proton gradient across the thylakoid membrane （ApH） and in acclimation to high light intensity conditions. Three PGR5 homoeologues were isolated from wheat, and mapped onto chromosomes 7A, 7B and 7D, respectively. The TaPGR5s shared highly similar genomic sequences and gene structures. The transcripts of TaPGR5s were found to be abundantly expressed in the flag leaves, and were transiently up-regulated by treatment with high light. High light treatment inhibited the net photosynthetic rate （Pn） and the maximal quantum yield ofphotosystem II （Fv/Fm）. Further, these inhibitions were more evident in the leaves with reduced expression of TaPGR5s achieved using virus-induced gene silencing methods. Moreover, reducing TaPGR5 expression impaired the induction of non-photochemical quenching （NPQ）, which caused more severe cell membrane damage and lipid peroxidation in high light. Additionally, we observed that TaPGR5s transcripts were more abundantly expressed in the wheat genotypes with higher ms-delayed light emission （ms-DLE）, a value reflecting transthylakoid ApH. These results suggested that TaPGR5s play important roles in the tolerance of wheat to photoinhibition.

Synthesis, Structure and Geometrical Calculation of a Novel Co-crystal of {[4-Bromo-2-(benzimidazol-2-yl)phenolato][2-(1-butylbenzimidazol-2-yl)phenolato]zinc(Ⅱ)] and Bis[μ-2-(1-butylbenzimidazol-2-yl)phenolato]-1κN^3:2κO;1κO:2κN^3-bis{[2-(1-butylbe

The title compound has been synthesized and characterized crystallographicaUy. It is a co-crystal consisting of two different neutral zinc（H） complexes with Hbpbm （Hbpbm = 4- bromo-2-（benzimidazol-2-yl）phenol） and Hnpbm （Hnpbm = 2-（1-butylbenzimidazol-2-yl）phenol）. One is a monomeric mixed-ligand complex of [Zn（bpbm）（npbm）] 1 and the other a dimer of [Zn2（npbm）4] 2 with their ratio of 2：1. Thus the overall formula for the title compound is 21.2. Adjacent 1 and 2 are connected to each other by intermolecular hydrogen bonding interactions in the lattice. The crystal data： monoclinic, space group P21/c, a = 15.0141（12）, b = 20.9941（17）, c = 18.4686（15） A, β = 97.445（2）°, V = 5772.4（8） A^3, Mr= 2429.68, Z = 2, Dc = 1.398 g/cm^3,μ = 1.579 -1 mm , F（000） = 2504, R = 0.0637 and wR = 0.1771 for 6464 observed reflections （I 〉 2σ（I））. The geometrical structure for 1 has also been theoretically optimized and compared with the experimental one.