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SUMMARYDrought and salt stress severely inhibit plant growth and development; however, the regulatory mechanisms of plants in response to these stresses are not fully understood. Here we report that the expression of a WRKY transcription factor WRKY46 is rapidly induced by drought, salt and oxidative stresses. T-DNA insertion of WRKY46 leads to more sensitivity to drought and salt stress, whereas overexpression of WRKY46 (OV46) results in hypersensitivity in soil-grown plants, with a higher water loss rate, but with increased tolerance on the sealed agar plates. Stomatal closing in the OV46 line is insensitive to ABA because of a reduced accumulation of reactive oxygen species (ROS) in the guard cells. We further find that WRKY46 is expressed in guard cells, where its expression is not affected by dehydration, and is involved in light-dependent stomatal opening. Microarray analysis reveals that WRKY46 regulates a set of genes involved in cellular osmoprotection and redox homeostasis under dehydration stress, which is confirmed by ROS and malondialdehyde (MDA) levels in stressed seedlings. Moreover, WRKY46 modulates light-dependent starch metabolism in guard cells via regulating QUA-QUINE STARCH (QQS) gene expression. Taken together, we demonstrate that WRKY46 plays dual roles in regulating plant responses to drought and salt stress and light-dependent stomatal opening in guard cells.

SUMMARYAluminum (Al) toxicity is the major limiting factor for crop production on acid soils, but the transcriptional regulation of Al tolerance genes is largely unknown. Here, we found that the expression of a WRKY domaincontaining transcription factor WRKY46 is inhibited by Al and expressed in root stele, whereas the expression of ALMT1, which encodes a malate efflux transporter, is induced by Al stress and spatially co-localized with WRKY46 in root stele, indicating the possible interaction between WRKY46 and ALMT1 in Arabidopsis. Mutation of WRKY46 by T-DNA insertion leads to better root growth under Al stress, and lower root Al content compared with the wild-type Col-0. The wrky46 mutant shows increased root malate secretion, which is consistent with the higher ALMT1 expression in the mutant. Transient expression analysis using truncated promoter of ALMT1 showed that ALMT1 expression can be inhibited by WRKY46 in tobacco leaves. The yeast one-hybrid assay and ChIP-qPCR analysis revealed that WRKY46 directly binds to ALMT1 promoter through specific W-boxes. Taken together, we demonstrated that WRKY46 is a negative regulator of ALMT1, mutation of WRKY46 leads to increased malate secretion and reduced Al accumulation in root apices, and thus confers higher Al resistance.

We construct a two-dimensional lattice model of fermions coupled to Ising ferromagnetic critical fluctuations. Using extensive sign-problem-free quantum Monte Carlo simulations, we show that the model realizes a continuous itinerant quantum phase transition. In comparison with other similar itinerant quantum critical points (QCPs), our QCP shows much weaker superconductivity tendency with no superconducting state down to the lowest temperature investigated, hence making the system a good platform for the exploration of quantum critical fluctuations. Remarkably, clear signatures of non-Fermi-liquid behavior in the fermion propagators are observed at the QCP. The critical fluctuations at the QCP partially resemble Hertz-Millis-Moriya behavior. However, careful scaling analysis reveals that the QCP belongs to a different universality class, deviating from both (2+1)d Ising and Hertz-Millis-Moriya predictions. arXiv:1612.06075v2 [cond-mat.str-el]

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Using large-scale quantum Monte Carlo simulations, we exactly solve a model of Fermions hopping on the honeycomb lattice with cluster charge interactions, which has been proposed as an effective model with possible application to twisted bilayer graphene near half-filling. We find an interaction driven semimetal to insulator transition to an insulating phase consisting of a valence bond solid with Kekulé pattern. Finite size scaling reveals that the phase transition of the semimetal to Kekulé valence bond solid phase is continuous and belongs to chiral XY universality class.

The interplay between lattice gauge theories and fermionic matter accounts for fundamental physical phenomena ranging from the deconfinement of quarks in particle physics to quantum spin liquid with fractionalized anyons and emergent gauge structures in condensed matter physics. However, except for certain limits (for instance large number of flavors of matter fields), analytical methods can provide few concrete results. Here we show that the problem of compact U(1) lattice gauge theory coupled to fermionic matter in (2 + 1)D is possible to access via sign-problem-free quantum Monte Carlo simulations. One can hence map out the phase diagram as a function of fermion flavors and the strength of gauge fluctuations. By increasing the coupling constant of the gauge field, gauge confinement in the form of various spontaneous symmetry breaking phases such as valence bond solid (VBS) and Néel antiferromagnet emerge. Deconfined phases with algebraic spin and VBS correlation functions are also observed. Such deconfined phases are incarnation of an exotic states of matter, i.e. the algebraic spin liquid, which is generally viewed as the parent state of various quantum phases. The phase transitions between deconfined and confined phases, as well as that between the different confined phases provide various manifestations of deconfined quantum criticality. In particular, for four flavors, N f = 4, our data suggests a continuous quantum phase transition between the VBS and Néel order. We also provide preliminary theoretical analysis for these quantum phase transitions.

Self-learning Monte Carlo method is a powerful general-purpose numerical method recently introduced to simulate many-body systems. In this work, we extend it to interacting fermion quantum system in the framework of widely used determinantal quantum Monte Carlo. The new method can generally reduce the computational complexity, and moreover can greatly suppress the autocorrelation time near a critical point. This enables us to simulate interacting fermion system on a 100 × 100 lattice even at the critical point for the first time, and obtain critical exponents with high precision.Introduction -Numerous intermetallic compounds hosting intriguing phenomena such as non-Fermi liquid[1] and unconventional superconductivity [2-4] emerging from quantum critical fluctuations (antiferromagnetic [2-4], nematic [5,6], etc), demand proper theoretical understanding of them. However, these systems are usually strongly correlated, and can only be solved by non-perturbative methods. In the last few years, after several attempts [7][8][9][10][11][12][13][14], people realize determinantal quantum Monte Carlo (DQMC) is one of the most suitable methods and sometimes even the only available choice.