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Chlorogenic acid is a key chemical in antioxidation and antisepsis. Sambucus chinensis L. is an herbaceous plant rich in chlorogenic acid and a potential genetic resource for breeding high‐chlorogenic acid plants. However, there are few studies on the synthesis pathway of chlorogenic acid in S. chinensis. Our study found chlorogenic acid accumulation in S. chinensis to be organ‐specific, higher in leaves and buds but lower in roots, stems and fruits. A total number of 546,844 CCS (circular consensus sequence), including 402,767 full‐length nonchimeric (FLNC) and 39 annotated sequences related to the synthesis of chlorogenic acid, was obtained by single‐molecule real‐time sequencing technology (SMRT). qRT‐PCR showed that a number of key genes involved in chlorogenic acid synthesis were differentially expressed in various tissues of S. chinensis. Transgenic tobacco revealed that ectopic expression of the HCT homologous gene HCT‐45178 increased the content of chlorogenic acid. Our results should be the first report of full‐length transcriptome data of S. chinensis, which help to understand the basis of chlorogenic acid synthesis and provide a novel strategy for breeding tobacco cultivars with higher levels of chlorogenic acid. [ABSTRACT FROM AUTHOR]

The lack of systematic structural resolution makes it difficult to build specific transition‐metal‐atom‐doped carbonized polymer dots (TMA‐doped CPDs). Herein, the structure‐activity relationship between Cu atoms and CPDs was evaluated by studying the peroxidase‐like properties of Glu−Cu−CPDs prepared by using copper glutamate (Glu) with a Cu−N2O2 initial structure. The results showed that the Cu atoms bound to Glu−Cu−CPDs in the form of Cu−N2C2, indicating that Cu−O bonds changed into Cu−C bonds under hydrothermal conditions. This phenomenon was also observed in other copper‐doped CPDs. Moreover, the carboxyl and amino groups content decreased after copper‐atom doping. Theoretical calculations revealed a dual‐site catalytic mechanism for catalyzing H2O2. The detection of intracellular H2O2 suggested their application prospects. Our study provides an in‐depth understanding of the formation and catalytic mechanism of TMA‐doped‐CPDs, allowing for the generation specific TMA‐doped‐CPDs. [ABSTRACT FROM AUTHOR]

Both rare‐earth doping and microgravity solidification processing bring significant influences upon the structure formation and mechanical properties of various alloys. Herein, the microstructure and performance of 13Cr martensitic stainless steel are modulated by adding minor Ce content and microgravity solidification by means of drop tube technique. The lattice structure of constituent phase α(Fe) is deformed evidently by microgravity solidification, and the lattice parameter variation is 1.8 times of that caused by Ce addition. The microstructures of this steel processed by arc melting consist of lath‐shaped martensites and a few feather‐shaped bainites whose volume fraction increases with the Ce content. The bainite is replaced by ferrite in the rapidly solidified microstructure of 13Cr steel under microgravity condition. Although both microgravity solidification and Ce addition induce the microstructure refinement and inclusion spheroidization, the former effect plays the dominant role. The compressive properties and microhardness decrease moderately with Ce addition due to the slight increase in bainite, however, the microgravity solidification brought the hardening effect and thus the microhardness of the steel droplets increases with undercooling. [ABSTRACT FROM AUTHOR]

Summary: Although increasing experimental evidence demonstrates that histone methylations play important roles in Arabidopsis plant growth and development, little information is available regarding Brassica napus. In this study, we characterized two genes encoding homologues of the Arabidopsis histone 3 lysine 36 (H3K36) methyltransferase SDG8, namely, BnaSDG8.A and BnaSDG8.C. Although no duplication of SDG8 homologous genes had been previously reported to occur during the evolution of any sequenced species, a domain‐duplication was uncovered in BnaSDG8.C. This duplication led to the identification of a previously unknown NNH domain in the SDG8 homologues, providing a useful reference for future studies and revealing the finer mechanism of SDG8 function. One NNH domain is present in BnaSDG8.A, while two adjacent NNH domains are present in BnaSDG8.C. Reverse transcriptase‐quantitative polymerase chain reaction analysis revealed similar patterns but with varied levels of expression of BnaSDG8.A/C in different plant organs/tissues. To directly investigate their function, BnaSDG8.A/C cDNA was ectopically expressed to complement the Arabidopsis mutant. We observed that the expression of either BnaSDG8.A or BnaSDG8.C could rescue the Arabidopsis sdg8 mutant to the wild‐type phenotype. Using RNAi and CRISPR/Cas9‐mediated gene editing, we obtained BnaSDG8.A/C knockdown and knockout mutants with the early flowering phenotype as compared with the control. Further analysis of two types of the mutants revealed that BnaSDG8.A/C are required for H3K36 m2/3 deposition and prevent the floral transition of B. napus by directly enhancing the H3K36 m2/3 levels at the BnaFLC chromatin loci. This observation on the floral transition by epigenetic modification in B. napus provides useful information for breeding early‐flowering varieties. [ABSTRACT FROM AUTHOR]

In tissue culture, the formation of callus from detached explants is a key step in plant regeneration; however, the regenerative abilities in different species are variable. While nearly all parts of organs of the dicot Arabidopsis thaliana are ready for callus formation, mature regions of organs in monocot rice ( Oryza sativa) and other cereals are extremely unresponsive to tissue culture. Whether there is a common molecular mechanism beyond these different regenerative phenomena is unclear. Here we show that the Arabidopsis and rice use different regeneration-competent cells to initiate callus, whereas the cells all adopt WUSCHEL-RELATED HOMEOBOX 11 ( WOX11) and WOX5 during cell fate transition. Different from Arabidopsis which maintains regeneration-competent cells in mature organs, rice exhausts those cells during organ maturation, resulting in regenerative inability in mature organs. Our study not only explains this old perplexity in agricultural biotechnology, but also provides common molecular markers for tissue culture of different angiosperm species. [ABSTRACT FROM AUTHOR]

Cytosolic sulphotransferases have been implicated in inactivation of endogenous steroid hormones and detoxification of xenobiotics in human and animals. Yet, the function of plant sulphotransferases in xenobiotic sulphonation and detoxification has not been reported. In this study, we show that the A rabidopsis sulphotransferase AtSOT12 could sulphonate the bacterial-produced toxin cycloheximide. Loss-of-function mutant sot12 exhibited hypersensitive phenotype to cycloheximide, and expression of AtSOT12 protein in yeast cells conferred resistance to this toxic compound. AtSOT12 exhibited broad specificity and could sulphonate a variety of xenobiotics including phenolic and polycyclic compounds. Enzyme kinetics analysis indicated that AtSOT12 has different selectivity for simple phenolics with different side chains, and the position of the side chain in the simple phenolic compounds affects substrate binding affinity and catalytic efficiency. We proposed that the broad specificity and induced production of AtSOT12 may have rendered this enzyme to not only modify endogenous molecules such as salicylic acid as we previously reported, but also sulphonate pathogen-produced toxic small molecules to protect them from infection. Sulphonation of small molecules in plants may constitute a rapid way to inactivate or change the physiochemical properties of biologically active molecules that could have profound effects on plant growth, development and defence. [ABSTRACT FROM AUTHOR]

BACKGROUND Flowering time is an important agronomic trait, and wide variation in flowering time exists among Brassica napus accessions. GX50 early-flowering mutant, induced from Brassica napus by Ethyl Methane Sulfonate (EMS), exhibits a remarkable early transition from vegetative to reproductive growth. RESULTS GX50 plants flowered about 60 days earlier than the control wild-type plant B. napus XY15 under greenhouse conditions. Cytological examination revealed that the GX50 plants form inflorescences as early as from 5 weeks old, flower primordium from 6 weeks old, and siliques from 10 weeks old, whereas 10-week-old XY15 plants are still at vegetative growth stage. To unravel the molecular mechanisms underlying the GX50 flowering phenotype, we analyzed the expression of several key regulatory genes. Expressions of all five BnaFLCs ( BnaFLC1 to BnaFLC5), BnaFT and BnaSOC1 were detected. Interestingly, BnaFLCs expression levels were lower in GX50 than those in XY15. Among the five BnaFLCs, only the expression pattern of BnaFLC2 corresponded to the timing of floral organ differentiation in GX50. In agreement with previous knowledge that BnaFLCs repress expression of BnaFT and BnaSOC1, increased levels of BnaFT and BnaSOC1 were observed in GX50 compared with XY15. CONCLUSION BnaFLC2, but not the other BnaFLC genes, plays an important role in B. napus GX50 floral transition. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Agrobacterium-mediated transformation is widely used in transgenic plant engineering and has been proven to be a powerful tool for insertional mutagenesis of the plant genome. The transferred DNA (T-DNA) from Agrobacterium is integrated into the plant genome through illegitimate recombination between the T-DNA and the plant DNA. Contrasting to the canonical insertion, here we report on a locus showing a complex mutation associated with T-DNA insertion at the BRI1 gene in Arabidopsis thaliana. We obtained a mutant line, named salade for its phenotype of dwarf stature and proliferating rosette. Molecular characterization of this mutant revealed that in addition to T-DNA a non-T-DNA-localized transposon from bacteria was inserted in the Arabidopsis genome and that a region of more than 11.5 kb of the Arabidopsis genome was deleted at the insertion site. The deleted region contains the brassinosteroid receptor gene BRI1 and the transcription factor gene WRKY13. Our finding reveals non-canonical T-DNA insertion, implicating horizontal gene transfer and cautioning the use of T-DNA as mutagen in transgenic research. [ABSTRACT FROM AUTHOR]

St John's wort extract (SJW; Hypericum perforatum L.) is taken extensively as a putative herbal antidepressant. It has been shown to induce the activity of cytochrome P-450 3A4 (CYP3A4) and to increase the clearance of numerous drugs and steroids such as cortisol and ethinyl estradiol. This study was conducted to determine if SJW exposure also alters the concentrations of circulating androgenic steroid hormones. The study was conducted using healthy volunteers (6M, 6F) studied before and after a 14-day treatment period with a SJW preparation previously demonstrated to induce the activity of CYP3A4. Plasma concentrations of testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG) and the combined concentrations of androsterone sulfate (AoS) and epiandrosterone sulfate (epiAoS) were measured by immunoassay methods. The results of analysis demonstrated that SJW did not significantly alter the majority of the androgens studied (p > 0.05) although the combined concentrations of the 5alpha-reduced steroids, AoS and epiAoS, significantly declined following treatment in all subjects (p = 0.02), and in males (p = 0.04). Furthermore, the testosterone to DHT ratio was increased in both men and women. Although the latter increase did not reach statistical significance, it is also consistent with the possible inhibition of 5alpha-reductase by SJW. It is concluded that despite significant induction of CYP3A4, short term administration of SJW does not significantly alter the concentrations of most circulating androgens in men and women but may produce a dimunition in some of the circulating 5alpha-reduced androgens. [ABSTRACT FROM AUTHOR]