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Owing to diverse abiotic stresses and global climate deterioration, the agricultural production worldwide is suffering serious losses. Breeding stress-resilient crops with higher quality and yield against multiple environmental stresses via application of transgenic technologies is currently the most promising approach. Deciphering molecular principles and mining stress-associate genes that govern plant responses against abiotic stresses is one of the prerequisites to develop stress-resistant crop varieties. As molecular switches in controlling stress-responsive genes expression, transcription factors (TFs) play crucial roles in regulating various abiotic stress responses. Hence, functional analysis of TFs and their interaction partners during abiotic stresses is crucial to perceive their role in diverse signaling cascades that many researchers have continued to undertake. Here, we review current developments in understanding TFs, with particular emphasis on their functions in orchestrating plant abiotic stress responses. Further, we discuss novel molecular mechanisms of their action under abiotic stress conditions. This will provide valuable information for understanding regulatory mechanisms to engineer stress-tolerant crops.

Topological insulators are materials that behave as insulators in the bulk and as conductors at the edge or surface due to the particular configuration of their bulk band dispersion. However, up to date possible practical applications of this band topology on materials’ bulk properties have remained abstract. Here, we propose and experimentally demonstrate a topological bulk laser. We pattern semiconductor nanodisk arrays to form a photonic crystal cavity showing topological band inversion between its interior and cladding area. In-plane light waves are reflected at topological edges forming an effective cavity feedback for lasing. This band-inversion-induced reflection mechanism induces single-mode lasing with directional vertical emission. Our topological bulk laser works at room temperature and reaches the practical requirements in terms of cavity size, threshold, linewidth, side-mode suppression ratio and directionality for most practical applications according to Institute of Electrical and Electronics Engineers and other industry standards. We believe this bulk topological effect will have applications in near-field spectroscopy, solid-state lighting, free-space optical sensing and communication.The interface between photonic crystals with distinct in-band topologies confines electromagnetic modes and gives rise to lasing emission in the bulk.

Plasmonics enables the manipulation of light beyond the optical diffraction limit 1 – 4 and may therefore confer advantages in applications such as photonic devices 5 – 7 , optical cloaking 8 , 9 , biochemical sensing 10 , 11 and super-resolution imaging 12 , 13 . However, the essential field-confinement capability of plasmonic devices is always accompanied by a parasitic Ohmic loss, which severely reduces their performance. Therefore, plasmonic materials (those with collective oscillations of electrons) with a lower loss than noble metals have long been sought 14 – 16 . Here we present stable sodium-based plasmonic devices with state-of-the-art performance at near-infrared wavelengths. We fabricated high-quality sodium films with electron relaxation times as long as 0.42 picoseconds using a thermo-assisted spin-coating process. A direct-waveguide experiment shows that the propagation length of surface plasmon polaritons supported at the sodium–quartz interface can reach 200 micrometres at near-infrared wavelengths. We further demonstrate a room-temperature sodium-based plasmonic nanolaser with a lasing threshold of 140 kilowatts per square centimetre, lower than values previously reported for plasmonic nanolasers at near-infrared wavelengths. These sodium-based plasmonic devices show stable performance under ambient conditions over a period of several months after packaging with epoxy. These results indicate that the performance of plasmonic devices can be greatly improved beyond that of devices using noble metals, with implications for applications in plasmonics, nanophotonics and metamaterials. A thermo-assisted spin-coating process followed by packaging is used to fabricate sodium films that are stable for several months, enabling the realization of plasmonic devices with state-of-the-art performance at near-infrared wavelengths.

Salinity and drought are major environmental factors limiting the growth and productivity of alfalfa worldwide as this economically important legume forage is sensitive to these kinds of abiotic stress. In this study, transgenic alfalfa lines expressing both tonoplast NXH and H⁺‐PPase genes, ZxNHX and ZxVP1‐1 from the xerophyte Zygophyllum xanthoxylum L., were produced via Agrobacterium tumefaciens‐mediated transformation. Compared with wild‐type (WT) plants, transgenic alfalfa plants co‐expressing ZxNHX and ZxVP1‐1 grew better with greater plant height and dry mass under normal or stress conditions (NaCl or water‐deficit) in the greenhouse. The growth performance of transgenic alfalfa plants was associated with more Na⁺, K⁺ and Ca²⁺ accumulation in leaves and roots, as a result of co‐expression of ZxNHX and ZxVP1‐1. Cation accumulation contributed to maintaining intracellular ions homoeostasis and osmoregulation of plants and thus conferred higher leaf relative water content and greater photosynthesis capacity in transgenic plants compared to WT when subjected to NaCl or water‐deficit stress. Furthermore, the transgenic alfalfa co‐expressing ZxNHX and ZxVP1‐1 also grew faster than WT plants under field conditions, and most importantly, exhibited enhanced photosynthesis capacity by maintaining higher net photosynthetic rate, stomatal conductance, and water‐use efficiency than WT plants. Our results indicate that co‐expression of tonoplast NHX and H⁺‐PPase genes from a xerophyte significantly improved the growth of alfalfa, and enhanced its tolerance to high salinity and drought. This study laid a solid basis for reclaiming and restoring saline and arid marginal lands as well as improving forage yield in northern China.

Plasmonic nanolasers are a new class of amplifiers that generate coherent light well below the diffraction barrier bringing fundamentally new capabilities to biochemical sensing, super-resolution imaging, and on-chip optical communication. However, a debate about whether metals can enhance the performance of lasers has persisted due to the unavoidable fact that metallic absorption intrinsically scales with field confinement. Here, we report plasmonic nanolasers with extremely low thresholds on the order of 10 kW cm −2 at room temperature, which are comparable to those found in modern laser diodes. More importantly, we find unusual scaling laws allowing plasmonic lasers to be more compact and faster with lower threshold and power consumption than photonic lasers when the cavity size approaches or surpasses the diffraction limit. This clarifies the long-standing debate over the viability of metal confinement and feedback strategies in laser technology and identifies situations where plasmonic lasers can have clear practical advantage. Since the first proposal for plasmonic nanolasers there has been a debate about the limitations on performance posed by the inherent losses in metallic systems. Here, the authors compare over 100 plasmonic and photonic laser devices and find sub-wavelength plasmonic lasers to be advantageous.

Background Atriplex canescens is a typical C 4 secretohalophyte with salt bladders on the leaves. Accumulating excessive Na + in tissues and salt bladders, maintaining intracellular K + homeostasis and increasing leaf organic solutes are crucial for A. canescens survival in harsh saline environments, and enhanced photosynthetic activity and water balance promote its adaptation to salt. However, the molecular basis for these physiological mechanisms is poorly understood. Four-week-old A. canescens seedlings were treated with 100 mM NaCl for 6 and 24 h, and differentially expressed genes in leaves and roots were identified, respectively, with Illumina sequencing. Results In A. canescens treated with 100 mM NaCl, the transcripts of genes encoding transporters/channels for important nutrient elements, which affect growth under salinity, significantly increased, and genes involved in exclusion, uptake and vacuolar compartmentalization of Na + in leaves might play vital roles in Na + accumulation in salt bladders. Moreover, NaCl treatment upregulated the transcripts of key genes related to leaf organic osmolytes synthesis, which are conducive to osmotic adjustment. Correspondingly, aquaporin-encoding genes in leaves showed increased transcripts under NaCl treatment, which might facilitate water balance maintenance of A. canescens seedlings in a low water potential condition. Additionally, the transcripts of many genes involved in photosynthetic electron transport and the C 4 pathway was rapidly induced, while other genes related to chlorophyll biosynthesis, electron transport and C 3 carbon fixation were later upregulated by 100 mM NaCl. Conclusions We identified many important candidate genes involved in the primary physiological mechanisms of A. canescens salt tolerance. This study provides excellent gene resources for genetic improvement of salt tolerance of important crops and forages.

Background Under saline conditions, Suaeda salsa , as a typical halophyte, accumulates large amounts of Na + in its leaves during optimal growth. Key transporters involved in Na + accumulation in plants are HKT-type protein, the plasma membrane Na + /H + transporter SOS1, and the tonoplast Na + /H + antiporter NHX1. In this study, the function of SsHKT1;1 and its coordinate expression with SsSOS1 and SsNHX1 to regulate Na + homeostasis in S. salsa was investigated. Results We showed, by yeast complementation assays, that SsHKT1;1 encoded a Na + -selective transporter, which located to the plasma membrane and was preferentially expressed within the stele, and was particularly abundant in xylem parenchyma and pericycle cells. When compared with a treatment of 25 mM NaCl, 150 mM NaCl greatly decreased the transcripts of SsHKT1;1 , but maintained a relatively constant level of the expression of SsSOS1 in roots. Consequently, the synergistic effect of SsHKT1;1 and SsSOS1 would result in greater Na + loading into the xylem under 150 mM NaCl than 25 mM NaCl. In leaves, 150 mM NaCl up-regulated the abundance of SsNHX1 compared with levels in 25 mM NaCl. This enabled the permanent sequestering of Na + into leaf vacuoles. Conclusions Overall, SsHKT1;1 functioned in reducing Na + retrieval from the root xylem, and played an important role in coordinating with SsSOS1 and SsNHX1 to maintain Na + accumulation in S. salsa under saline conditions.

The drift history of the Lhasa terrane is crucial for understanding the tectonic evolution of Tethyan Oceans and Jurassic true polar wander. However, high‐quality Middle Jurassic paleomagnetic data from the Lhasa terrane are limited in number. Here we report a combined paleomagnetic and geochronologic study on the Yeba Formation volcanic rocks, dated at ∼170 Ma, from the Lhasa terrane. Robust field and reversal tests indicate that the characteristic remanent magnetizations are primary. Our results provide a reliable Middle Jurassic (∼170 Ma) paleopole at 29.8°N, 180.7°E with A95 = 5.7° and a paleolatitude of 14.4 ± 5.7°N for the Lhasa area. Compared with previous paleomagnetic and geologic evidence, we propose that the Meso‐Tethys Ocean probably began to close in the eastern part at ∼168 Ma and that the Lhasa terrane underwent a ∼2,900 km southward “monster shift” during the Late Jurassic. Plain Language Summary The formation of the Tibetan Plateau followed the breakup of the Gondwana supercontinent and was associated with the demise of several Tethyan Oceans. The Lhasa terrane, which is a long and narrow continental fragment derived from Gondwana, was isolated in the Tethyan Ocean during the Jurassic and finally accreted to the south margin of the Paleo‐Asia continent, leading to the closure of the Meso‐Tethys Ocean. However, when this Meso‐Tethys Ocean closed is still controversial. Our new robust paleomagnetic result shows that the Lhasa terrane was located at ∼14.4°N at ∼170 Ma. Based on available reliable Jurassic paleomagnetic data from the eastern part of the Lhasa and Qiangtang terranes, we suggest that the Meso‐Tethys Ocean began to close in the eastern part at ∼168 Ma. Integrating our critical Middle Jurassic paleomagnetic data with that of the Late Jurassic from the Lhasa terrane, we argue that the Lhasa terrane suffered a ∼2,900 km southward latitudinal shift during the Late Jurassic, which is known as true polar wander. Key Points The Lhasa terrane was located at ∼14.4 ± 5.7°N at ∼170 Ma The Lhasa terrane experienced a ∼2,900 km southward monster shift during the Late Jurassic The closure of the Meso‐Tethys Ocean in the eastern part most likely occurred at ∼168 Ma

Background and aims Uncontrolled uptake of Na + is the reason that many species are sensitive to salinity. Suberin is a protective barrier found in the walls of root endodermal cells that appears to be important for salt tolerance, yet its specific protective mechanism has not been fully elucidated. Methods Here we investigated the role of aliphatic suberin in protecting plants against salt stress by using a mutant of Arabidopsis, cyp86a1 , which exhibits a significant reduction of root aliphatic suberin. Results We found that NaCl significantly increased suberization in roots of hydroponic-grown wild-type plants, but not in cyp86a1 . Cyp86a1 exhibited a salt-sensitive phenotype. Compared with wild-type, Na + accumulation in shoots was higher in cyp86a1 . We provide evidence that increased Na + uptake was via the root transcellular pathway. Furthermore, cyp86a1 accumulated less K + in shoots than wild-type under NaCl stress, which was a consequence of increased K + efflux from the root vasculature. Additionally, we provide evidence that aliphatic suberin reduces inflow of water across the root endodermis under non-stress conditions but reduces the backflow of water to the medium under salt stress. Conclusions Finally, we propose a model for the role of aliphatic suberin in restricting Na + influx, K + efflux and water backflow in plants under saline conditions.

is a typical salt-excluding halophytic grass with excellent salt tolerance. Plasma membrane Na /H transporter SOS1, HKT-type protein and tonoplast Na /H antiporter NHX1 are key Na transporters involved in plant salt tolerance. Based on our previous research, we had proposed a function model for these transporters in Na homeostasis according to the expression of and Na , K levels in responding to salt stress. Here, we analyzed the expression patterns of , , and in under 25 and 150 mM NaCl to further validate this model by combining previous physiological characteristics. Results showed that the expressions of and in roots were significantly induced and peaked at 6 h under both 25 and 150 mM NaCl. Compared to the control, the expression of significantly increased by 5.8-folds, while that of increased only by 1.2-folds in roots under 25 mM NaCl; on the contrary, the expression of increased by 1.4-folds, whereas that of increased by 2.2-folds in roots under 150 mM NaCl. In addition, was induced instantaneously under 25 mM NaCl, while its expression was much higher and more persistent in shoots under 150 mM NaCl. These results provide stronger evidences for the previous hypothesis and extend the model which highlights that SOS1, HKT1;5, and NHX1 synergistically regulate Na homeostasis by controlling Na transport systems at the whole-plant level under both lower and higher salt conditions. Under mild salinity, PtNHX1 in shoots compartmentalized Na into vacuole slowly, and vacuole potential capacity for sequestering Na would enhance Na loading into the xylem of roots by PtSOS1 through feedback regulation; and consequently, Na could be transported from roots to shoots by transpiration stream for osmotic adjustment. While under severe salinity, Na was rapidly sequestrated into vacuoles of mesophyll cells by PtNHX1 and the vacuole capacity became saturated for sequestering more Na , which in turn regulated long-distance Na transport from roots to shoots. As a result, the expression of was strongly induced so that the excessive Na was unloaded from xylem into xylem parenchyma cells by PtHKT1;5.