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研究发现增强植物根内共生和养分获取能力的新思路 快报文章
资源环境快报,2025年第2期
作者:  董利苹,杜海霞
Microsoft Word(15Kb)  |  收藏  |  浏览/下载:462/0  |  提交时间:2025/01/31
Autoactive CNGC15  Root Endosymbiosis  Enhance  
Strain engineering and epitaxial stabilization of halide perovskites 期刊论文
NATURE, 2020, 577 (7789) : 209-+
作者:  Chen, Yimu;  Lei, Yusheng;  Li, Yuheng;  Yu, Yugang;  Cai, Jinze;  Chiu, Ming-Hui;  Rao, Rahul;  Gu, Yue;  Wang, Chunfeng;  Choi, Woojin;  Hu, Hongjie;  Wang, Chonghe;  Li, Yang;  Song, Jiawei;  Zhang, Jingxin;  Qi, Baiyan;  Lin, Muyang;  Zhang, Zhuorui;  Islam, Ahmad E.;  Maruyama, Benji;  Dayeh, Shadi;  Li, Lain-Jong;  Yang, Kesong;  Lo, Yu-Hwa;  Xu, Sheng
收藏  |  浏览/下载:48/0  |  提交时间:2020/07/03

Strain engineering is a powerful tool with which to enhance semiconductor device performance(1,2). Halide perovskites have shown great promise in device applications owing to their remarkable electronic and optoelectronic properties(3-5). Although applying strain to halide perovskites has been frequently attempted, including using hydrostatic pressurization(6-8), electrostriction(9), annealing(10-12), van der Waals force(13), thermal expansion mismatch(14), and heat-induced substrate phase transition(15), the controllable and device-compatible strain engineering of halide perovskites by chemical epitaxy remains a challenge, owing to the absence of suitable lattice-mismatched epitaxial substrates. Here we report the strained epitaxial growth of halide perovskite single-crystal thin films on lattice-mismatched halide perovskite substrates. We investigated strain engineering of a-formamidinium lead iodide (alpha-FAPbI(3)) using both experimental techniques and theoretical calculations. By tailoring the substrate composition-and therefore its lattice parameter-a compressive strain as high as 2.4 per cent is applied to the epitaxial alpha-FAPbI(3) thin film. We demonstrate that this strain effectively changes the crystal structure, reduces the bandgap and increases the hole mobility of alpha-FAPbI(3). Strained epitaxy is also shown to have a substantial stabilization effect on the alpha-FAPbI(3) phase owing to the synergistic effects of epitaxial stabilization and strain neutralization. As an example, strain engineering is applied to enhance the performance of an alpha-FAPbI(3)-based photodetector.


  
Confinement of atomically defined metal halide sheets in a metal-organic framework 期刊论文
NATURE, 2020, 577 (7788) : 64-+
作者:  Gonzalez, Miguel I.;  Turkiewicz, Ari B.;  Darago, Lucy E.;  Oktawiec, Julia;  Bustillo, Karen;  Grandjean, Fernande;  Long, Gary J.;  Long, Jeffrey R.
收藏  |  浏览/下载:24/0  |  提交时间:2020/07/03

The size-dependent and shape-dependent characteristics that distinguish nanoscale materials from bulk solids arise from constraining the dimensionality of an inorganic structure(1-3). As a consequence, many studies have focused on rationally shaping these materials to influence and enhance their optical, electronic, magnetic and catalytic properties(4-6). Although a select number of stable clusters can typically be synthesized within the nanoscale regime for a specific composition, isolating clusters of a predetermined size and shape remains a challenge, especially for those derived from two-dimensional materials. Here we realize a multidentate coordination environment in a metal-organic framework to stabilize discrete inorganic clusters within a porous crystalline support. We show confined growth of atomically defined nickel(ii) bromide, nickel(ii) chloride, cobalt(ii) chloride and iron(ii) chloride sheets through the peripheral coordination of six chelating bipyridine linkers. Notably, confinement within the framework defines the structure and composition of these sheets and facilitates their precise characterization by crystallography. Each metal(ii) halide sheet represents a fragment excised from a single layer of the bulk solid structure, and structures obtained at different precursor loadings enable observation of successive stages of sheet assembly. Finally, the isolated sheets exhibit magnetic behaviours distinct from those of the bulk metal halides, including the isolation of ferromagnetically coupled large-spin ground states through the elimination of long-range, interlayer magnetic ordering. Overall, these results demonstrate that the pore environment of a metal-organic framework can be designed to afford precise control over the size, structure and spatial arrangement of inorganic clusters.


  
RGF1 controls root meristem size through ROS signalling 期刊论文
NATURE, 2020, 577 (7788) : 85-+
作者:  Yamada, Masashi;  Han, Xinwei;  Benfey, Philip N.
收藏  |  浏览/下载:25/0  |  提交时间:2020/07/03

The stem cell niche and the size of the root meristem in plants are maintained by intercellular interactions and signalling networks involving a peptide hormone, root meristem growth factor 1 (RGF1)(1). Understanding how RGF1 regulates the development of the root meristem is essential for understanding stem cell function. Although five receptors for RGF1 have been identified(2-4), the downstream signalling mechanism remains unknown. Here we report a series of signalling events that follow RGF1 activity. We find that the RGF1-receptor pathway controls the distribution of reactive oxygen species (ROS) along the developmental zones of the Arabidopsis root. We identify a previously uncharacterized transcription factor, RGF1-INDUCIBLE TRANSCRIPTION FACTOR 1 (RITF1), that has a central role in mediating RGF1 signalling. Manipulating RITF1 expression leads to the redistribution of ROS along the root developmental zones. Changes in ROS distribution in turn enhance the stability of the PLETHORA2 protein, a master regulator of root stem cells. Our results thus clearly depict a signalling cascade that is initiated by RGF1, linking this peptide to mechanisms that regulate ROS.


  
Internal state dynamics shape brainwide activity and foraging behaviour 期刊论文
NATURE, 2020, 577 (7789) : 239-+
作者:  Marques, Joao C.;  Li, Meng;  Schaak, Diane;  Robson, Drew N.;  Li, Jennifer M.
收藏  |  浏览/下载:20/0  |  提交时间:2020/07/03

The brain has persistent internal states that can modulate every aspect of an animal'  s mental experience(1-4). In complex tasks such as foraging, the internal state is dynamic(5-8). Caenorhabditis elegans alternate between local search and global dispersal(5). Rodents and primates exhibit trade-offs between exploitation and exploration(6,7). However, fundamental questions remain about how persistent states are maintained in the brain, which upstream networks drive state transitions and how state-encoding neurons exert neuromodulatory effects on sensory perception and decision-making to govern appropriate behaviour. Here, using tracking microscopy to monitor whole-brain neuronal activity at cellular resolution in freely moving zebrafish larvae(9), we show that zebrafish spontaneously alternate between two persistent internal states during foraging for live prey (Paramecia). In the exploitation state, the animal inhibits locomotion and promotes hunting, generating small, localized trajectories. In the exploration state, the animal promotes locomotion and suppresses hunting, generating long-ranging trajectories that enhance spatial dispersion. We uncover a dorsal raphe subpopulation with persistent activity that robustly encodes the exploitation state. The exploitation-state-encoding neurons, together with a multimodal trigger network that is associated with state transitions, form a stochastically activated nonlinear dynamical system. The activity of this oscillatory network correlates with a global retuning of sensorimotor transformations during foraging that leads to marked changes in both the motivation to hunt for prey and the accuracy of motor sequences during hunting. This work reveals an important hidden variable that shapes the temporal structure of motivation and decision-making.


  
Brain control of humoral immune responses amenable to behavioural modulation 期刊论文
NATURE, 2020, 581 (7807)
作者:  Yang, C. H.;  Leon, R. C. C.;  Hwang, J. C. C.;  Saraiva, A.;  Tanttu, T.;  Huang, W.;  Lemyre, J. Camirand;  Chan, K. W.;  Tan, K. Y.;  Hudson, F. E.;  Itoh, K. M.;  Morello, A.;  Pioro-Ladriere, M.;  Laucht, A.;  Dzurak, A. S.
收藏  |  浏览/下载:27/0  |  提交时间:2020/07/03

It has been speculated that brain activities might directly control adaptive immune responses in lymphoid organs, although there is little evidence for this. Here we show that splenic denervation in mice specifically compromises the formation of plasma cells during a T cell-dependent but not T cell-independent immune response. Splenic nerve activity enhances plasma cell production in a manner that requires B-cell responsiveness to acetylcholine mediated by the alpha 9 nicotinic receptor, and T cells that express choline acetyl transferase(1,2) probably act as a relay between the noradrenergic nerve and acetylcholine-responding B cells. We show that neurons in the central nucleus of the amygdala (CeA) and the paraventricular nucleus (PVN) that express corticotropin-releasing hormone (CRH) are connected to the splenic nerve  ablation or pharmacogenetic inhibition of these neurons reduces plasma cell formation, whereas pharmacogenetic activation of these neurons increases plasma cell abundance after immunization. In a newly developed behaviour regimen, mice are made to stand on an elevated platform, leading to activation of CeA and PVN CRH neurons and increased plasma cell formation. In immunized mice, the elevated platform regimen induces an increase in antigen-specific IgG antibodies in a manner that depends on CRH neurons in the CeA and PVN, an intact splenic nerve, and B cell expression of the alpha 9 acetylcholine receptor. By identifying a specific brain-spleen neural connection that autonomically enhances humoral responses and demonstrating immune stimulation by a bodily behaviour, our study reveals brain control of adaptive immunity and suggests the possibility to enhance immunocompetency by behavioural intervention.


Neuronal activities in the central amygdala and paraventricular nucleus are transmitted via the splenic nerve to increase plasma cell formation after immunization, and this process can be behaviourally enhanced in mice.


  
Plant 22-nt siRNAs mediate translational repression and stress adaptation 期刊论文
NATURE, 2020, 581 (7806) : 89-+
作者:  Roulis, Manolis;  Kaklamanos, Aimilios;  Schernthanner, Marina;  Bielecki, Piotr;  Zhao, Jun;  Kaffe, Eleanna;  Frommelt, Laura-Sophie;  Qu, Rihao;  Knapp, Marlene S.;  Henriques, Ana;  Chalkidi, Niki;  Koliaraki, Vasiliki;  Jiao, Jing;  Brewer, J. Richard;  Bacher, Maren;  Blackburn, Holly N.;  Zhao, Xiaoyun;  Breyer, Richard M.;  Aidinis, Vassilis;  Jain, Dhanpat;  Su, Bing;  Herschman, Harvey R.;  Kluger, Yuval;  Kollias, George;  Flavell, Richard A.
收藏  |  浏览/下载:54/0  |  提交时间:2020/07/03

Characterization of 22-nucleotide short interfering RNAs in plants finds that they accumulate in response to environmental stress, causing translational repression, inhibition of plant growth and enhanced stress responses.


Small interfering RNAs (siRNAs) are essential for proper development and immunity in eukaryotes(1). Plants produce siRNAs with lengths of 21, 22 or 24 nucleotides. The 21- and 24-nucleotide species mediate cleavage of messenger RNAs and DNA methylation(2,3), respectively, but the biological functions of the 22-nucleotide siRNAs remain unknown. Here we report the identification and characterization of a group of endogenous 22-nucleotide siRNAs that are generated by the DICER-LIKE 2 (DCL2) protein in plants. When cytoplasmic RNA decay and DCL4 are deficient, the resulting massive accumulation of 22-nucleotide siRNAs causes pleiotropic growth disorders, including severe dwarfism, meristem defects and pigmentation. Notably, two genes that encode nitrate reductases-NIA1 and NIA2-produce nearly half of the 22-nucleotide siRNAs. Production of 22-nucleotide siRNAs triggers the amplification of gene silencing and induces translational repression both gene specifically and globally. Moreover, these 22-nucleotide siRNAs preferentially accumulate upon environmental stress, especially those siRNAs derived from NIA1/2, which act to restrain translation, inhibit plant growth and enhance stress responses. Thus, our research uncovers the unique properties of 22-nucleotide siRNAs, and reveals their importance in plant adaptation to environmental stresses.


  
The fate of carbon in a mature forest under carbon dioxide enrichment 期刊论文
NATURE, 2020, 580 (7802) : 227-+
作者:  Sun, P. Z.;  Yang, Q.;  Kuang, W. J.;  Stebunov, Y. V.;  Xiong, W. Q.;  Yu, J.;  Nair, R. R.;  Katsnelson, M. I.;  Yuan, S. J.;  Grigorieva, I. V.;  Lozada-Hidalgo, M.;  Wang, F. C.;  Geim, A. K.
收藏  |  浏览/下载:89/0  |  提交时间:2020/05/13

Carbon dioxide enrichment of a mature forest resulted in the emission of the excess carbon back into the atmosphere via enhanced ecosystem respiration, suggesting that mature forests may be limited in their capacity to mitigate climate change.


Atmospheric carbon dioxide enrichment (eCO(2)) can enhance plant carbon uptake and growth(1-5), thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO2 concentration(6). Although evidence gathered from young aggrading forests has generally indicated a strong CO2 fertilization effect on biomass growth(3-5), it is unclear whether mature forests respond to eCO(2) in a similar way. In mature trees and forest stands(7-10), photosynthetic uptake has been found to increase under eCO(2) without any apparent accompanying growth response, leaving the fate of additional carbon fixed under eCO(2) unclear(4,5,7-11). Here using data from the first ecosystem-scale Free-Air CO2 Enrichment (FACE) experiment in a mature forest, we constructed a comprehensive ecosystem carbon budget to track the fate of carbon as the forest responded to four years of eCO(2) exposure. We show that, although the eCO(2) treatment of +150 parts per million (+38 per cent) above ambient levels induced a 12 per cent (+247 grams of carbon per square metre per year) increase in carbon uptake through gross primary production, this additional carbon uptake did not lead to increased carbon sequestration at the ecosystem level. Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone accounting for half of the total uptake surplus. Our results call into question the predominant thinking that the capacity of forests to act as carbon sinks will be generally enhanced under eCO(2), and challenge the efficacy of climate mitigation strategies that rely on ubiquitous CO2 fertilization as a driver of increased carbon sinks in global forests.


  
Fundamental bounds on the fidelity of sensory cortical coding 期刊论文
NATURE, 2020
作者:  Rempel, S.;  Gati, C.;  Nijland, M.;  Thangaratnarajah, C.;  Karyolaimos, A.;  de Gier, J. W.;  Guskov, A.;  Slotboom, D. J.
收藏  |  浏览/下载:29/0  |  提交时间:2020/07/03

How the brain processes information accurately despite stochastic neural activity is a longstanding question(1). For instance, perception is fundamentally limited by the information that the brain can extract from the noisy dynamics of sensory neurons. Seminal experiments(2,3) suggest that correlated noise in sensory cortical neural ensembles is what limits their coding accuracy(4-6), although how correlated noise affects neural codes remains debated(7-11). Recent theoretical work proposes that how a neural ensemble'  s sensory tuning properties relate statistically to its correlated noise patterns is a greater determinant of coding accuracy than is absolute noise strength(12-14). However, without simultaneous recordings from thousands of cortical neurons with shared sensory inputs, it is unknown whether correlated noise limits coding fidelity. Here we present a 16-beam, two-photon microscope to monitor activity across the mouse primary visual cortex, along with analyses to quantify the information conveyed by large neural ensembles. We found that, in the visual cortex, correlated noise constrained signalling for ensembles with 800-1,300 neurons. Several noise components of the ensemble dynamics grew proportionally to the ensemble size and the encoded visual signals, revealing the predicted information-limiting correlations(12-14). Notably, visual signals were perpendicular to the largest noise mode, which therefore did not limit coding fidelity. The information-limiting noise modes were approximately ten times smaller and concordant with mouse visual acuity(15). Therefore, cortical design principles appear to enhance coding accuracy by restricting around 90% of noise fluctuations to modes that do not limit signalling fidelity, whereas much weaker correlated noise modes inherently bound sensory discrimination.


A microscopy system that enables simultaneous recording from hundreds of neurons in the mouse visual cortex reveals that the brain enhances its coding capacity by representing visual inputs in dimensions perpendicular to correlated noise.


  
Control and single-shot readout of an ion embedded in a nanophotonic cavity 期刊论文
NATURE, 2020, 580 (7802) : 201-+
作者:  Rollie, Clare;  Chevallereau, Anne;  Watson, Bridget N. J.;  Chyou, Te-yuan;  Fradet, Olivier;  McLeod, Isobel;  Fineran, Peter C.;  Brown, Chris M.;  Gandon, Sylvain;  Westra, Edze R.
收藏  |  浏览/下载:44/0  |  提交时间:2020/07/03

Distributing entanglement over long distances using optical networks is an intriguing macroscopic quantum phenomenon with applications in quantum systems for advanced computing and secure communication(1,2). Building quantum networks requires scalable quantum light-matter interfaces(1) based on atoms(3), ions(4) or other optically addressable qubits. Solid-state emitters(5), such as quantum dots and defects in diamond or silicon carbide(6-10), have emerged as promising candidates for such interfaces. So far, it has not been possible to scale up these systems, motivating the development of alternative platforms. A central challenge is identifying emitters that exhibit coherent optical and spin transitions while coupled to photonic cavities that enhance the light-matter interaction and channel emission into optical fibres. Rare-earth ions in crystals are known to have highly coherent 4f-4f optical and spin transitions suited to quantum storage and transduction(11-15), but only recently have single rare-earth ions been isolated(16,17) and coupled to nanocavities(18,19). The crucial next steps towards using single rare-earth ions for quantum networks are realizing long spin coherence and single-shot readout in photonic resonators. Here we demonstrate spin initialization, coherent optical and spin manipulation, and high-fidelity single-shot optical readout of the hyperfine spin state of single Yb-171(3+) ions coupled to a nanophotonic cavity fabricated in an yttrium orthovanadate host crystal. These ions have optical and spin transitions that are first-order insensitive to magnetic field fluctuations, enabling optical linewidths of less than one megahertz and spin coherence times exceeding thirty milliseconds for cavity-coupled ions, even at temperatures greater than one kelvin. The cavity-enhanced optical emission rate facilitates efficient spin initialization and single-shot readout with conditional fidelity greater than 95 per cent. These results showcase a solid-state platform based on single coherent rare-earth ions for the future quantum internet.


Single ytterbium ion qubits in nanophotonic cavities have long coherence times and can be optically read out in a single shot, establishing them as excellent candidates for optical quantum networks.