H2 Complex Research Articles

Ultrahigh growth rate-induced thick 3C-SiC heteroepitaxial layers on 4H-SiC and its oxidation characteristics

The cubic 3C-SiC displays unique advantages in power electronics applications due to its high channel mobility and low SiO2/3C-SiC interface state density. Therefore, the epitaxial growth technology of 3C-SiC is one of the core technologies for preparing high-performance SiC power devices. In this work, we choose 4H-SiC as substrates to grow 3C-SiC with methyltrichlorosilane (MTS)-H2 complex precursor and acheieved an ultrahigh epitaxial growth rate up to 278 μm/h. Then the oxidation treatment has been conducted. The elemental composition, surface morphology, and crystalline phase of the prepared 3C-SiC/4H–SiC thick films were comprehensively characterized with SEM, Raman, XRD and TEM techniques. The growth mechanism and oxidation characteristics of the 3C-SiC/4H-SiC heteroepitaxial layers were analyzed based on experimental phenomena.

Polygenic TB control and the sequence of innate/adaptive immune responses to infection: MHC-II alleles determine the size of the S100A8/9-producing neutrophil population.

Among several quantitative trait loci involved in tuberculosis (TB) control in mice, one was mapped within the chromosome 17 segment occupied by the H2 complex and another within the chromosome 3 segment comprising the S100A8/9 genes, which encode neutrophil inflammatory factor S100A8/9. Previously, we developed a panel of H2-congenic mouse strains differing by small segments of the major histocompatibility complex Class II (MHC-II) region from TB-susceptible H2j mice transferred onto the genetic background of the TB-resistant C57BL/6 (H2b) strain. Susceptible B6.I-9.3 mice differ from B6 progenitors by the alleles of their only classical MHC-II H2-Aβ gene. The goals of the present study were to: (i) comprehensively characterise the differences in TB-related phenotypes between mice of the two strains and (ii) decipher interactions between the H2-Aβ and S100A8/9 genes. Here, we describe the dynamics of TB-related phenotypes differentiating B6.I-9.3 and B6 mice (colony forming unitscounts, histopathology, lung immune cell infiltration and cytokine profiles). We show that disproportionally diminished CD4+ T-cell population, an enlarged S100A8/9-positive neutrophil population and higher S100A8/9 serum levels in B6.I-9.3 mice collectively form the 'susceptible' phenotype before infection. An increase in IL-17 and a decrease in intrferon-gamma production by CD4+ T-cells in these mice provide a mechanistic explanation of this phenotype. Using F2 segregation analysis, we show that the number of S100A8/9-producing neutrophils in lungs and spleens and the proportion of Th17 CD4+ T-cells in lungs are significantly lower in the presence of the MHC-II dominant 'resistant' b allele compared to the recessive 'susceptible' j/j genotype. This provides direct genetic evidence that MHC-II-regulated CD4+ T-cell landscapes determine neutrophil abundance before infection, an important pathogenic factor in TB immunity.

Spectroscopic and Theoretical Insights into H2 Activation on Uranium Monoxide: Homolytic H2 Cleavage Mediated by Intermediate OU(η2-H2).

Elucidating molecular-level interactions between dihydrogen (H2) and uranium oxides reveals fundamental insights into the intrinsic H2 activation mechanisms underlying processes such as heterogeneous catalysis over uranium oxides and corrosion of uranium induced by H2. Herein, the reactions of H2 with uranium monoxide (UO) molecules have been investigated via a combination of matrix-isolation infrared spectroscopy and quantum chemical calculations. A side-on bonded H2 complex, OU(η2-H2), is identified at 3733.7 and 800.3 cm-1. This species is regarded as a crucial intermediate along H2 activation pathways. Bonding analysis reveals cooperative U(π5f/6d) → H2(σ*) π// backdonation and U ← H2(σ) σ donation in OU(η2-H2) that facilitate the activation of the H2 moiety. Upon λ > 550 nm photoirradiation, OU(η2-H2) isomerizes into H2UO, indicating the homolytic H2 cleavage on UO. Mechanistic details of H2 adsorption and dissociation on UO molecules have been further elucidated.

The H2-A Class II molecule α/β-chain cis-mismatch severely affects cell surface expression, selection of conventional CD4+ T cells and protection against TB infection.

To dissect the role of the part of the H2 complex comprised of the MHC-II genes in the control of tuberculosis (TB) infection, we previously established a panel of recombinant congenic mouse strains bearing different segments of the H2 j haplotype on the B6 (H2 b) genetic background. Fine genetic mapping, gene sequencing and assessment of TB phenotypes resulted in identification of the H2-Ab gene as a major factor of TB control. We further narrowed the MHC-II H2 j interval by spotting a new recombination event, sequencing newly established DNA configuration and establishing a mouse strain B6.I-103 in which j/b recombination occurred within the coding sequence of the H2-Ab gene. Unexpectedly, a novel H2-Aα b/AβjE0 haplotype provided exclusively high susceptibility to TB challenge. Immunologic analysis revealed an altered CD4+ T-cell selection and maintenance in B6.I-103 mice, as well as seriously impaired expression of the H2-Aαb/Aβj molecule on the surface of antigen presenting cells. Unlike previously reported cases of Class II malfunctioning, the defective phenotype arose not from strong structural mutations, but from regular recombination events within the MHC-II recombination hot spot region. Our findings provide evidence that Class II α/β-chain cis-allelic mismatches created by regular genetic recombination may severely affect immune system functioning. This issue is discussed in the context of the MHC evolution.

Collisional excitation of C2H- by H2: New interaction potential and scattering calculations.

Interstellar anions play an important role in astrochemistry as being tracers of the physical and chemical conditions in cold molecular clouds and circumstellar gas. The local thermodynamic equilibrium is generally not fulfilled in media where anions are detected and radiative and collisional data are required to model the observed lines. The C2H- anion has not yet been detected in the interstellar medium; however, collisional data could be used for non-LTE models that would help in identifying the most intense lines. For this purpose, we have computed the first 4D potential energy surface (PES) of the C2H--H2 complex using an explicitly correlated coupled-cluster approach. The PES is characterized by a single deep minimum with a well-depth of 924.96 cm-1. From this interaction potential, we derived excitation cross sections and rate coefficients of C2H- induced by collisions with para- and ortho-H2. The results obtained for collisions with para-H2 are compared to previous calculations performed using a 2D-PES obtained from an average over H2 rotations.

Boosting Photo-Electro-Fenton Process Via Atomically Dispersed Iron Sites on Graphdiyne for InVitro Hydrogen Peroxide Detection.

Hydrogen peroxide (H2 O2 ) is essential in oxidative stress and signal regulation of organs of animal body. Realizing in vitro quantification of H2 O2 released from organs is significant, but faces challenges due to short lifetime of H2 O2 and complex bio-environment. Herein, rationally designed and constructed a photoelectrochemical (PEC) sensor for in vitro sensing of H2 O2 , in which atomically dispersed iron active sites (Hemin) modified graphdiyne (Fe-GDY) serves as photoelectrode and catalyzes photo-electro-Fenton process. Sensitivity of Fe-GDY electrode is enhanced 8 times under illumination compared with dark condition. The PEC H2 O2 sensor under illumination delivers a wide linear range from 0.1 to 48 160µm and a low detection limit of 33nm, while demonstrating excellent selectivity and stability. The high performance of Fe-GDY is attributed to, first, energy levels matching of GDY and Hemin that effectively promotes the injection of photo-generated electrons from GDY to Fe3+ for reduced Fe2+ , which facilitates the Fe3+ /Fe2+ cycle. Second, the Fe2+ actively catalyzes H2 O2 to OH- through the Fenton process, thereby improving the sensitivity. The PEC sensor demonstrates in vitro quantification of H2 O2 released from different organs, providing a promising approach for molecular sensing and disease diagnosis in organ levels.

CRISPR/Cas12a-based MUSCA-PEC strategy for HSV-1 assay

In the photoelectrochemical sensing, constant potential excitation to get the photoelectrochemical signal is the main excitation signal mode. Novel method for photoelectrochemical signal obtaining is needed. Inspired by this ideal, a photoelectrochemical strategy for Herpes simplex virus (HSV-1) detection with multiple potential step chronoamperometry (MUSCA) pattern was fabricated using CRISPR/Cas12a cleavage coupled with entropy-driven target recycling. In the presence of target, HSV-1, the Cas12a was activated by the H1–H2 complex obtained by entropy-driven, then digesting the circular fragment of csRNA to expose single-stranded crRNA2 and alkaline phosphatase (ALP). The inactive Cas12a was self-assembled with crRNA2 and activated again with the help of assistant dsDNA. After multiple rounds of CRISPR/Cas12a cleavage and magnetic separation, MUSCA, as a signal amplifier, collected the enhanced photocurrent responses generated by catalyzed p-Aminophenol (p-AP). Different from the reported signal enhancement strategies based on photoactive nanomaterials and sensing mechanisms, MUSCA technique endowed the strategy with unique advantages of direct, fast and ultrasensitive. A superior detection limit of 3 aM toward HSV-1 was achieved. This strategy was successfully applied for HSV-1 detection in Human serum samples. The combination of MUSCA technique and CRISPR/Cas12a assay brings broader potential prospect for the detection of nucleic acids.

Defect and interstitial B synergistically promote the stability and H2 dissociation of Pd6 supported by graphene

As a potential hydrogenation catalyst, palladium nanoparticles supported by graphene encounter three major problems: transition metal agglomeration, interstitial H atom, and the competition between desorption of H2 and Pdn-Hx complex from graphene sheet. In this paper, defects and interstitial B are used to promote the stability and H2 dissociation of Pd6 supported by graphene. The introduction of defects increases the binding energy of Pd, Pd6 and Pd6B to graphene by a factor of 5–7 and 7–9 before and after hydrogen adsorption, respectively. It indicates that defects can effectively avoid the desorption competition between PdnHx and hydrogen molecules. Moreover, the energy barrier of dissociation for the first hydrogen molecule on Pd6B/C49 is 0.49 eV, which is lower than 0.75 eV on Pd6/C49 and 0.69 eV on Ti6/C49.

Engineering an endonuclease-assisted rolling circle amplification synergistically catalyzing hairpin assembly mediated fluorescence platform for miR-21 detection

As one of the earliest miRNAs discovered in the human genome, miRNA-21 can provide vital information for the early diagnosis, drug treatment, and prognosis of cancers. Herein, we construct a fast, time-saving fluorescence detection system for miRNA-21 detection by coalescing the improved endonuclease-mediated rolling circle amplification with catalytic hairpin assembly (RCA-NESA-CHA). Firstly, the target miRNA cyclized the padlock, initiating rolling circle amplification (RCA) and extending a long-concatenated DNA. The modified Protector bonded with the long-strand DNA to generate an endonuclease-specific site and trigger the nicking process. Finally, DNA products with repetitive sequences not only recombined with the padlock to reactivate a new recycle of RCA but also triggered the catalytic hairpin assembly to form the H1–H2 complex, realizing the cooperative amplification of the signal. In this system, RCA-NESA and CHA were integrated into one step, which essentially simplifies the sensing process. Moreover, the introduction of the Protector would inhibit the extension reaction caused by the combination of the padlock and the RCA products, slowing down the non-specific reaction time and improving the sensitivity of the fluorescence detection system. Under the optimal experimental conditions, the fluorescence system achieved a limit-of-detection of 0.025 amol miR-21 in a 40 μL sample and successfully applied to miR-21 detection in serum samples from breast cancer patients, showing good agreement with the results of RT-PCR, which exhibited great potential in biomedical research and clinical diagnosis.

Pattern analysis of the impact‐parameter dependent trajectories for the H + H2 exchange reaction at T = 3 and 300 K: A characteristic propensity for reactive versus nonreactive trajectories found in the time‐dependent interaction potential and a roaming‐like libration motion at cold temperature

AbstractPattern analysis of the impact‐parameter dependent trajectory for the H + H2 exchange reaction was performed at temperatures T = 3 and 300 K by employing the quasi‐classical trajectory calculation on a London‐Eyring‐Polanyi‐Sato surface. We find that (a) 0.66 fraction of reactive trajectories throughout b = 0.0 ~ 5.0 Å at T = 3 K, while only 0.33 at T = 300 K only for b = 0.0 ~ 1.5 Å and decreases soon to zero for b = 2.5 ~ 5.0 Å. (b) Ninety eight percent of the trajectories showed direct collision pattern at T = 300 K, while at T = 3 K, 72% for direct collision trajectories and 28% showed the intermediate H + H2 complex formation pattern. These results suggest that nonzero impact‐parameter trajectories play a role at T = 3 K to enhance reactivity due to long‐range attraction forces. Trajectory pattern analysis reveals a characteristic propensity rule between the amplitude of the time‐dependent interaction potential and the trajectory reactivity, thus we can judge if a trajectory is reactive or nonreactive. The analysis also proposes a roaming‐like libration motion at T = 3 K like in the interstellar clouds.

Deexcitation rate coefficients of C3 by collision with H2 at low temperatures

Context. An accurate analysis of the physical-chemical conditions in the regions of the interstellar medium in which C3 is observed requires knowing the collisional rate coefficients of this molecule with He, H2, electrons, and H. Aims. The main goals of this study are to present the first potential energy surface for the C3 +H2 complex, to study the dynamics of the system, and to report a set of rate coefficients at low temperature for the lower rotational states of C3 with para- and ortho-H2. Methods. A large grid of ab initio energies was computed at the explicitly correlated coupled-cluster with single-, double-, and perturbative triple-excitation level of theory, together with the augmented correlation-consistent quadruple zeta basis set (CCSD(T)-F12a/aug-cc-pVQZ). This grid of energies was fit to an analytical function. The potential energy surface was employed in close-coupling calculations at low collisional energies. Results. We present a high-level four-dimensional potential energy surface (PES) for studying the collision of C3 with H2. The global minimum of the surface is found in the linear HH-CCC configuration. Rotational deexcitation state-to-state cross sections of C3 by collision with para- and ortho-H2 are computed. Furthermore, a reduced two-dimensional surface is developed by averaging the surface over the orientation of H2. The cross sections for the collision with para-H2 using this approximation and those from the four-dimensional PES agree excellently. Finally, a set of rotational rate coefficients for the collision of C3 with para- and ortho-H2 at low temperatures are reported.

Trans Influence of Boryl Ligands in CO2 Hydrogenation on Ruthenium Complexes: Theoretical Prediction of Highly Active Catalysts for CO2 Reduction

In this work, we study the trans influence of boryl ligands and other commonly used non-boryl ligands in order to search for a more active catalyst than the ruthenium dihydride complex Ru(PNP)(CO)H2 for the hydrogenation of CO2. The theoretical calculation results show that only the B ligands exhibit a stronger trans influence than the hydride ligand and are along increasing order of trans influence as follows: –H < –BBr2 < –BCl2 ≈ –B(OCH)2 < –Bcat < –B(OCH2)2 ≈ –B(OH)2 < –Bpin < –B(NHCH2)2 < –B(OCH3)2 < –B(CH3)2 < –BH2. The computed activation free energy for the direct hydride addition to CO2 and the NBO analysis of the property of the Ru–H bond indicate that the activity of the hydride can be enhanced by the strong trans influence of the B ligands through the change in the Ru–H bond property. The function of the strong trans influence of B ligands is to decrease the d orbital component of Ru in the Ru–H bond. The design of a more active catalyst than the Ru(PNP)(CO)H2 complex is possible.

A DOT1B/Ribonuclease H2 Protein Complex Is Involved in R-Loop Processing, Genomic Integrity, and Antigenic Variation in Trypanosoma brucei.

ABSTRACTThe parasite Trypanosoma brucei periodically changes the expression of protective variant surface glycoproteins (VSGs) to evade its host’s immune system in a process known as antigenic variation. One route to change VSG expression is the transcriptional activation of a previously silent VSG expression site (ES), a subtelomeric region containing the VSG genes. Homologous recombination of a different VSG from a large reservoir into the active ES represents another route. The conserved histone methyltransferase DOT1B is involved in transcriptional silencing of inactive ES and influences ES switching kinetics. The molecular machinery that enables DOT1B to execute these regulatory functions remains elusive, however. To better understand DOT1B-mediated regulatory processes, we purified DOT1B-associated proteins using complementary biochemical approaches. We identified several novel DOT1B interactors. One of these was the RNase H2 complex, previously shown to resolve RNA-DNA hybrids, maintain genome integrity, and play a role in antigenic variation. Our study revealed that DOT1B depletion results in an increase in RNA-DNA hybrids, accumulation of DNA damage, and ES switching events. Surprisingly, a similar pattern of VSG deregulation was observed in RNase H2 mutants. We propose that both proteins act together in resolving R-loops to ensure genome integrity and contribute to the tightly regulated process of antigenic variation.

Ultra-sensitive and high efficiency detection of multiple non-small cell lung cancer-related miRNAs on a single test line in catalytic hairpin assembly-based SERS-LFA strip

Accurate quantification of multiple miRNAs biomarkers in body fluid is still a challenge for early screening of cancer. Herein, by catalytic hairpin assembly as a signal amplification strategy, we designed a novel surface-enhanced Raman scattering (SERS)-lateral flow assay (LFA) strip for ultrasensitive detection of miR-21 and miR-196a-5p in non-small cell lung cancer (NSCLC) urine on a single test (T) line. 4-mercaptobenzoic acid or 5,5′-dithiobis-2-nitrobenzoic acid as Raman molecules was labeled and two hairpin DNA sequence was modified gold nanocages (GNCs) were designed as two SERS tags. Through target miRNA-triggered catalytic hairpin assembly (CHA), the double-stranded DNAs (H1–H2 complex) formed by SERS tags and the related hairpin-structured DNA sequence 2 (H2) were immobilized on a single T line of SERS-LFA strip. This generated abundant “hot spots” because of the formation of numerous H1–H2 complex thus facilitated the SERS measurement. Through this method, two kinds of miRNAs were analyzed, resulting in limits of detection of 2.08 pM and 3.31 pM for miR-21 in PBS buffer and human urine, 1.77 pM and 2.18 pM for miR-196a-5p in PBS buffer and human urine. Significantly, the SERS-LFA strip exhibited high specificity and good repeatability toward miRNAs. The whole detection time was only 30 min, which means that the high detection efficiency of the strip. The clinical feasibility of the proposed method was also evaluated by detecting the levels of miR-21 and miR-196a-5p in urine samples from NSCLC patients and healthy subjects. The developed SERS-LFA strip has wide application prospect in biomedical research, drug development and early clinical diagnosis.

The Reaction of Hydrogen Halides with Tetrahydroborate Anion and Hexahydro-closo-hexaborate Dianion.

The mechanism of the consecutive halogenation of the tetrahydroborate anion [BH4]− by hydrogen halides (HX, X = F, Cl, Br) and hexahydro-closo-hexaborate dianion [B6H6]2− by HCl via electrophile-induced nucleophilic substitution (EINS) was established by ab initio DFT calculations [M06/6-311++G(d,p) and wB97XD/6-311++G(d,p)] in acetonitrile (MeCN), taking into account non-specific solvent effects (SMD model). Successive substitution of H− by X− resulted in increased electron deficiency of borohydrides and changes in the character of boron atoms from nucleophilic to highly electrophilic. This, in turn, increased the tendency of the B–H bond to transfer a proton rather than a hydride ion. Thus, the regularities established suggested that it should be possible to carry out halogenation more selectively with the targeted synthesis of halogen derivatives with a low degree of substitution, by stabilization of H2 complex, or by carrying out a nucleophilic substitution of B–H bonds activated by interaction with Lewis acids (BL3).

An accurate 5D potential energy surface for H3O+-H2 interaction.

Modeling of the observational spectra of H3O+ allows for a detailed understanding of the interstellar oxygen chemistry. While its spectroscopy was intensively studied earlier, our knowledge about the collision of H3O+ with the abundant colliders in the interstellar medium is rather limited. In order to treat these collisional excitation processes, it is first necessary to calculate the potential energy surface (PES) of the interacting species. We have computed the five-dimensional rigid-rotor PES of the H3O+-H2 system from the explicitly correlated coupled-cluster theory at the level of singles and doubles with perturbative corrections for triple excitations [CCSD(T)-F12] with the moderate-size augmented correlation-consistent valence triple zeta (aug-cc-pVTZ) basis set. The well depth of the PES is found to be rather large, about 1887.2 cm-1. The ab initio potential was fitted over an angular expansion in order to effectively use it in quantum scattering codes. As a first application, we computed dissociation energies for the different nuclear spin isomers of the H3O+-H2 complex.

A Genome-Wide Screen for Genes Affecting Spontaneous Direct-Repeat Recombination in Saccharomyces cerevisiae.

Homologous recombination is an important mechanism for genome integrity maintenance, and several homologous recombination genes are mutated in various cancers and cancer-prone syndromes. However, since in some cases homologous recombination can lead to mutagenic outcomes, this pathway must be tightly regulated, and mitotic hyper-recombination is a hallmark of genomic instability. We performed two screens in Saccharomyces cerevisiae for genes that, when deleted, cause hyper-recombination between direct repeats. One was performed with the classical patch and replica-plating method. The other was performed with a high-throughput replica-pinning technique that was designed to detect low-frequency events. This approach allowed us to validate the high-throughput replica-pinning methodology independently of the replicative aging context in which it was developed. Furthermore, by combining the two approaches, we were able to identify and validate 35 genes whose deletion causes elevated spontaneous direct-repeat recombination. Among these are mismatch repair genes, the Sgs1-Top3-Rmi1 complex, the RNase H2 complex, genes involved in the oxidative stress response, and a number of other DNA replication, repair and recombination genes. Since several of our hits are evolutionarily conserved, and repeated elements constitute a significant fraction of mammalian genomes, our work might be relevant for understanding genome integrity maintenance in humans.

Time-Resolved EPR Study of H2 Reductive Elimination from the Photoexcited Nitrogenase Janus E4(4H) Intermediate

Nitrogenase is activated for N2 reduction through the accumulation of four reducing equivalents at the active-site FeMo-cofactor (FeMo-co: Fe7S9MoC; homocitrate) to form the key Janus intermediate, denoted E4(4H), whose lowest-energy structure contains two [Fe-H-Fe] bridging hydrides and two protons bound to the sulfurs that also bridge the Fe pairs. In the critical step of catalysis, a H2 complex transiently produced by reductive elimination (re) of the hydrides of E4(4H), denoted E4(H2;2H), undergoes H2 displacement by N2, which then undergoes the otherwise energetically unfavorable cleavage of the N≡N triple bond. In pursuing the study of the re activation process, we have employed a photochemical approach to obtaining its atomic-level details. Continuous 450 nm irradiation of the ground state of the dihydride Janus intermediate, denoted E4(4H)a, in an EPR cavity at cryogenic temperatures causes photoinduced re of H2 to generate E4(H2;2H). We here extend this photochemical approach with time-resolved EPR studies of the photolysis process on the ns time scale. These studies reveal an additional intermediate in the catalytic reductive elimination process, an isomer of the E4(4H) FeMo-co metal-ion core that is formed prior to E4(H2;2H) and is thought to be created by breaking an Fe-SH bond, thus further integrating the calculational and structural studies into the experimentally determined mechanism by which nitrogenase is activated to cleave the N≡N triple bond.

Genome instability consequences of RNase H2 Aicardi-Goutières syndrome alleles

The RNase H2 complex is a conserved heterotrimeric enzyme that degrades RNA:DNA hybrids and promotes excision of rNMPs misincorporated during DNA replication. Failure to remove ribonucleotides from DNA leads to genomic instability in yeast and humans. The monogenic Aicardi-Goutières syndrome (AGS) results from mutation in one of several genes, among which are those encoding the RNase H2 subunits. The complete cellular and genomic consequences of RNASEH2 mutations and the precise connection to disease remain unclear. To learn more about the effect of RNASEH2 mutations on the cell, we used yeast as a model of AGS disease. We have generated yeast strains bearing AGS-associated mutations in RNASEH2 genes. There is a range of disease presentation in patients bearing these RNASEH2 variants. Here we report on in vivo phenotypes of genomic instability, including mutation and recombination rates, and synthetic gene interactions. These phenotypes provide insight into molecular consequences of RNASEH2 mutations, and lay the groundwork for further study of genomic instability as a contributing factor to AGS disease.

DNA damage and reactive oxygen species cause cell death in the rice local lesions 1 mutant under high light and high temperature.

High light and high temperature (HLHT) stress may become more frequent and severe as the climate changes, affecting crop growth and resulting in reduced production. However, the mechanism of the response to HLHT stress in rice is not yet fully understood. In the present study, we screened a rice mutant library using HLHT conditions and isolated an HLHT-sensitive mutant, local lesions 1 (ls1), which showed decreased pigment contents, defective stomata and chloroplasts, and a local lesions phenotype under HLHT. We characterized and cloned LS1 by map-based cloning and genetic complementation. LS1 encodes the A subunit of the RNase H2 complex (RNASEH2A). Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and comet assays indicated that mutation of LS1 led to severe DNA damage under HLHT stress. Furthermore, we found excessive reactive oxygen species (ROS) accumulation in the ls1 mutant under HLHT stress. Exogenous antioxidants eased the local lesions phenotype of the ls1 mutant under HLHT. DNA damage caused by HLHT stress induces ROS accumulation, which causes the injury and apoptosis of leaf cells in the ls1 mutant. These results enhance our understanding of the regulatory mechanism in the response to HLHT stress in higher plants.