作者机构:
[Huang, Xingchuan; Sun, Tongjun; Li, Xin; Xu, Yan; Huang, Jianhua] Univ British Columbia, Michael Smith Labs, Vancouver, BC V6T 1Z4, Canada.;[Sun, Tongjun; Zhang, Yuelin; Li, X; Jetter, Reinhard; Li, Xin; Xu, Yan; Tian, Hainan; Sun, Yulin; Huang, Jianhua] Univ British Columbia, Dept Bot, Vancouver, BC V6T 1Z4, Canada.;[Schafer, Laurel; Jetter, Reinhard; Orduna, Alberto Ruiz; Verma, Vani] Univ British Columbia, Dept Chem, Vancouver, BC V6T 1Z4, Canada.;[Jing, Beibei] Natl Inst Biol Sci, Beijing 102206, Peoples R China.;[Tian, Hainan] Northeast Normal Univ, Sch Life Sci, Changchun, Peoples R China.
通讯机构:
[Li, Xin; Zhang, YL; Li, X] U;Univ British Columbia, Michael Smith Labs, Vancouver, BC V6T 1Z4, Canada.;Univ British Columbia, Dept Bot, Vancouver, BC V6T 1Z4, Canada.
摘要:
Two signal molecules, salicylic acid (SA) and N-hydroxypipecolic acid (NHP), play critical roles in plant immunity. The biosynthetic genes of both compounds are positively regulated by master immune-regulating transcription factors SARD1 and CBP60g. However, the relationship between the SA and NHP pathways is unclear. CALMODULIN-BINDING TRANSCRIPTION FACTOR 1 (CAMTA1), CAMTA2, and CAMTA3 are known redundant negative regulators of plant immunity, but the underlying mechanism also remains largely unknown. In this study, through chromatin immunoprecipitation and electrophoretic mobility shift assays, we uncovered that CBP60g is a direct target of CAMTA3, which also negatively regulates the expression of SARD1, presumably via an indirect effect. The autoimmunity of camta3-1 is suppressed by sard1 cbp60g double mutant as well as ald1 and fmo1, two single mutants defective in NHP biosynthesis. Interestingly, a suppressor screen conducted in the camta1/2/3 triple mutant background yielded various mutants blocking biosynthesis or signaling of either SA or NHP, leading to nearly complete suppression of the extreme autoimmunity of camta1/2/3, suggesting that the SA and NHP pathways can mutually amplify each other. Together, these results reveal that CAMTAs repress the biosynthesis of SA and NHP by modulating the expression of SARD1 and CBP60g, and that the SA and NHP pathways are coordinated to optimize plant immune response.
摘要:
Metal-free g-C3N4 is always limited by low surface area, rapid charge recombination and limited visible light absorption. In this study, novel porous nitrogen self-doped g-C3N4 nanosheets were prepared by a combination of N self-doping and thermal exfoliation process. Compared to the bulk g-C3N4, N self-doped g-C3N4 nanosheets possessed a high specific surface area of 74.79m(2)g(-1), enhanced visible light absorption, improved photogenerated electron-holes separation, and prolonged lifetime of photogenerated charge carriers. As a consequence, N self-doped g-C3N4 nanosheets exhibited higher photocatalytic activity for tetracycline (TC) degradation than that of bulk g-C3N4, N self-doped g-C3N4 and g-C3N4 nanosheets. It also exhibited remarkable stability and repeatability. The detailed photocatalytic mechanism was proposed. The midgap states created by N doping can significantly enlarge the visible light absorption, reduce the recombination and prolong the lifetime of photogenerated charge carries. The nanosheet construction can provide increased surface area, abundant active sites, short charge diffusion distance, fast separation and promoted redox abilities of photoexcited charge carries.
作者:
Wu, Zhongshou;Li, Meng;Dong, Oliver Xiaoou;Xia, Shitou;Liang, Wanwan;...
期刊:
New Phytologist,2019年222(2):938-953 ISSN:0028-646X
通讯作者:
Li, Xin
作者机构:
[Dong, Oliver Xiaoou; Wu, Zhongshou; Liang, Wanwan; Li, Xin; Bao, Yongkang] Univ British Columbia, Michael Smith Labs, Vancouver, BC V6T 1Z4, Canada.;[Wasteneys, Geoffrey; Dong, Oliver Xiaoou; Wu, Zhongshou; Li, Meng; Liang, Wanwan; Li, Xin] Univ British Columbia, Dept Bot, Vancouver, BC V6T 1Z4, Canada.;[Xia, Shitou] Hunan Agr Univ, Hunan Prov Key Lab Phytohormones, Changsha 410128, Hunan, Peoples R China.
通讯机构:
[Li, Xin] U;Univ British Columbia, Michael Smith Labs, Vancouver, BC V6T 1Z4, Canada.;Univ British Columbia, Dept Bot, Vancouver, BC V6T 1Z4, Canada.
摘要:
Emerging contaminants have recently been recognized as new and significant water pollutants and gained great of concerns because of their considerable effects on ecosystems and human health. Current conventional wastewater treatment technologies are not efficient at removing these trace contaminants: novel and lower cost approaches are required. Biochar is well-known as an effective adsorbent for the removal of complex inorganic contaminants and organic contaminants from water. This review provides a summary of recent research on the underlying mechanisms controlling the presence of emerging contaminants in water, as well as their removal and the environmental treatment of soil by biochar. A range of information is also presented regarding the application of this resource: it is clear that a variety of cheap, efficient, modified, and composite biochar that is able to remove emerging contaminants will be required to further advance research progress. (C) 2018 Elsevier Ltd. All rights reserved.
通讯机构:
[Xia, Shitou; Zhao, Bingran] H;[Li, Hongqing] S;Hunan Agr Univ, Coll Biosci & Biotechnol, Hunan Prov Key Lab Phytohormones & Growth Dev, Changsha 410128, Hunan, Peoples R China.;Hunan Hybrid Rice Res Ctr, State Key Lab Hybrid Rice, Changsha 410125, Hunan, Peoples R China.;South China Normal Univ, Guangdong Prov Key Lab Biotechnol Plant Dev, Guangzhou 510631, Guangdong, Peoples R China.
摘要:
Rice grain with excessive cadmium (Cd) is a major source of dietary Cd intake and a serious threat to health for people who consume rice as a staple food. The development of elite rice cultivars with consistently low Cd content is challenging for conventional breeding approaches, and new strategies urgently need to be developed. Here, we report the development of new indica rice lines with low Cd accumulation and no transgenes by knocking out the metal transporter gene OsNramp5 using CRISPR/Cas9 system. Hydroponic culture showed that Cd concentrations in shoots and roots of osnramp5 mutants were dramatically decreased, resulting in rescue of impaired growth in high Cd condition. Cd-contaminated paddy field trials demonstrated that Cd concentration in osnramp5 grains was consistently less than 0.05 mg/kg, in contrast to high Cd concentrations from 0.33 mg/kg to 2.90 mg/kg in grains of Huazhan (the wild-type indica rice). In particular, the plant yield was not significantly affected in osnramp5 mutants. Furthermore, we developed promising hybrid rice lines with extremely low Cd content in grains. Our work supplies a practical approach to developing Cd pollution-safe indica rice cultivars that minimizes Cd contamination risk in grains.
摘要:
Miscanthus is a leading bioenergy candidate for biofuels, and it thus becomes essential to characterize the desire natural Miscanthus germplasm accessions with high biomass saccharification. In this study, total 171 natural Miscanthus accessions were geographically mapped using public database. According to the equation [P(H/L| East) = P(H/L∩East)/P(East)], the probability (P) parameters were calculated on relationships between geographical distributions of Miscanthus accessions in the East of China, and related factors with high(H) or low(L) values including biomass saccahrification under 1% NaOH and 1% H2SO4 pretreatments, lignocellulose features and climate conditions. Based on the maximum P value, a golden cutting line was generated from 42°25’ N, 108°22’ E to 22°58’ N, 116°28’ E on the original locations of Miscanthus accessions with high P(H|East) values (0.800–0.813), indicating that more than 90% Miscanthus accessions were originally located in the East with high biomass saccharification. Furthermore, the averaged insolation showed high P (H|East) and P(East|H) values at 0.782 and 0.754, whereas other climate factors had low P(East|H) values, suggesting that the averaged insolation is unique factor on Miscanthus distributions for biomass saccharification. In terms of cell wall compositions and wall polymer features, both hemicelluloses level and cellulose crystallinity (CrI) of Miscanthus accessions exhibited relative high P values, suggesting that they should be the major factors accounting for geographic distributions of Miscanthus accessions with high biomass digestibility.
摘要:
L-Cysteine is a nutritionally semi-essential amino acid and is present mainly in the form of L-cystine in the extracellular space. With the help of a transport system, extracellular L-cystine crosses the plasma membrane and is reduced to L-cysteine within cells by thioredoxin and reduced glutathione (GSH). Intracellular L-cysteine plays an important role in cellular homeostasis not only as a precursor for protein synthesis, but also for the production of GSH, H2 S, and taurine. L-Cysteine-dependent synthesis of GSH has been investigated in many pathological conditions, while the pathway for L-cysteine metabolism to form H2 S has received little attention with regard to prevention and treatment of disease in humans. The main objective of this review is to highlight the metabolic pathways of L-cysteine catabolism to GSH, H2 S, and taurine, with special emphasis on therapeutic and nutritional use of L-cysteine to improve the health and well-being of animals and humans This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
摘要:
MAX2 (for MORE AXILLARY GROWTH2) has been shown to regulate diverse biological processes, including plant architecture, photomorphogenesis, senescence, and karrikin signaling. Although karrikin is a smoke-derived abiotic signal, a role for MAX2 in abiotic stress response pathways is least investigated. Here, we show that the max2 mutant is strongly hypersensitive to drought stress compared with wild-type Arabidopsis (Arabidopsis thaliana). Stomatal closure of max2 was less sensitive to abscisic acid (ABA) than that of the wild type. Cuticle thickness of max2 was significantly thinner than that of the wild type. Both of these phenotypes of max2 mutant plants correlate with the increased water loss and drought-sensitive phenotype. Quantitative real-time reverse transcription-polymerase chain reaction analyses showed that the expression of stress-responsive genes and ABA biosynthesis, catabolism, transport, and signaling genes was impaired in max2 compared with wild-type seedlings in response to drought stress. Double mutant analysis of max2 with the ABA-insensitive mutants abi3 and abi5 indicated that MAX2 may function upstream of these genes. The expression of ABA-regulated genes was enhanced in imbibed max2 seeds. In addition, max2 mutant seedlings were hypersensitive to ABA and osmotic stress, including NaCl, mannitol, and glucose. Interestingly, ABA, osmotic stress, and drought-sensitive phenotypes were restricted to max2, and the strigolactone biosynthetic pathway mutants max1, max3, and max4 did not display any defects in these responses. Taken together, these results uncover an important role for MAX2 in plant responses to abiotic stress conditions.
关键词:
Rice;Spiders;Drosophila melanogaster;Food web structure;Arthropoda;Genetically modified plants;Pest control;Spider webs
摘要:
Cry proteins are expressed in rice lines for lepidopteran pest control. These proteins can be transferred from transgenic rice plants to non-target arthropods, including planthoppers and then to a predatory spider. Movement of Cry proteins through food webs may reduce fitness of non-target arthropods, although recent publications indicated no serious changes in non-target populations. Nonetheless, Cry protein intoxication influences gene expression in Cry-sensitive insects. We posed the hypothesis that Cry protein intoxication influences enzyme activities in spiders acting in tri-trophic food webs. Here we report on the outcomes of experiments designed to test our hypothesis with two spider species. We demonstrated that the movement of CryAb protein from Drosophila culture medium into fruit flies maintained on the CryAb containing medium and from the flies to the spiders Ummeliata insecticeps and Pardosa pseudoannulata. We also show that the activities of three key metabolic enzymes, acetylcholine esterase (AchE), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were significantly influenced in the spiders after feeding on Cry1Ab-containing fruit flies. We infer from these data that Cry proteins originating in transgenic crops impacts non-target arthropods at the physiological and biochemical levels, which may be one mechanism of Cry protein-related reductions in fitness of non-target beneficial predators.
摘要:
Plants must effectively defend against biotic and abiotic stresses to survive in nature. However, this defense is costly and is often accompanied by significant growth inhibition. How plants coordinate the fluctuating growth-defense dynamics is not well understood and remains a fundamental question. Jasmonate (JA) and gibberellic acid (GA) are important plant hormones that mediate defense and growth, respectively. Binding of bioactive JA or GA ligands to cognate receptors leads to proteasome-dependent degradation of specific transcriptional repressors (the JAZ or DELLA family of proteins), which, at the resting state, represses cognate transcription factors involved in defense (e.g., MYCs) or growth [e.g. phytochrome interacting factors (PIFs)]. In this study, we found that the coi1 JA receptor mutants of rice (a domesticated monocot crop) and Arabidopsis (a model dicot plant) both exhibit hallmark phenotypes of GA-hypersensitive mutants. JA delays GA-mediated DELLA protein degradation, and the della mutant is less sensitive to JA for growth inhibition. Overexpression of a selected group of JAZ repressors in Arabidopsis plants partially phenocopies GA-associated phenotypes of the coi1 mutant, and JAZ9 inhibits RGA (a DELLA protein) interaction with transcription factor PIF3. Importantly, the pif quadruple (pifq) mutant no longer responds to JA-induced growth inhibition, and overexpression of PIF3 could partially overcome JA-induced growth inhibition. Thus, a molecular cascade involving the COI1-JAZ-DELLA-PIF signaling module, by which angiosperm plants prioritize JA-mediated defense over growth, has been elucidated.