Search bioRxiv⌕ Search

Biology subjects

Bai, J.

Publications and source records attributed to Bai, J..

At least 91 records · Page 5Linked to original sources

SAINT: automatic taxonomy embedding and categorization by Siamese triplet network

MotivationUnderstanding the phylogenetic relationship among organisms is the key in contemporary evolutionary study and sequence analysis is the workhorse towards this goal. Conventional approaches to sequence analysis are based on sequence alignment, which is neither scalable to large-scale datasets due to computational inefficiency nor adaptive to next-generation sequencing (NGS) data. Alignment-free approaches are typically used as computationally effective alternatives yet still suffering the high demand of memory consumption. One desirable sequence comparison method at large-scale requires succinctly-organized sequence data management, as well as prompt sequence retrieval given a never-before-seen sequence as query. ResultsIn this paper, we proposed a novel approach, referred to as SAINT, for efficient and accurate alignment-free sequence comparison. Compared to existing alignment-free sequence comparison methods, SAINT offers advantages in two aspects: (1) SAINT is a weakly-supervised learning method where the embedding function is learned automatically from the easily-acquired data; (2) SAINT utilizes the non-linear deep learning-based model which potentially better captures the complicated relationship among genome sequences. We have applied SAINT to real-world datasets to demonstrate its empirical utility, both qualitatively and quantitatively. Considering the extensive applicability of alignment-free sequence comparison methods, we expect SAINT to motivate a more extensive set of applications in sequence comparison at large scale. AvailabilityThe open source, Apache licensed, python-implemented code will be available upon acceptance. Supplementary informationSupplementary data are available at Bioinformatics online.

bioinformatics↗

All-Flesh Tomato Regulated by Reduced Dosage of AFF Provides New Insights into Berry Fruit Evolution

The formation of locule gel is not only an important developmental process in tomato but also a typical characteristic of berry fruit. In this study, we collected a tomato material that produces all-flesh fruits (AFF), whose locule tissue remains in a solid state during fruit development. We built genetic populations to fine map the causal gene of AFF trait, investigate the function of AFF gene, and identified it as the causal locus conferring the locule gel formation. We determined the causal mutation as a 416-bp deletion that occurred in the promoter region of AFF, which reduces the expression dosage of AFF. The 416-bp deleted sequence has a high level of conservation among closely related Solanaceae species, as well as in the tomato population. The activity of the 416-bp deletion in down-regulating gene expression was further verified by the relative activity in a luciferase experiment. Furthermore, with the BC6 NIL materials, we reveal that the reduced expression dosage of AFF does not impact the normal development of seeds, while produces non-liquefied locule tissue, which is distinct from that of the normal tomatoes in terms of metabolic components. Based on these findings, we propose that the AFF gene is the core node in locule tissue liquefaction, whose function cannot be compensated by its paralogs TAG1, TAGL1, or TAGL11. Our findings provide clues to investigate fruit type differentiation among Solanaceae crops, and also contributes to the breeding application of all flesh fruit tomatoes for the tomato processing industry. One Sentence SummaryThe sequence deletion that occurred in the cis-regulatory region of AFF--the core node of locule tissue liquefaction determined here--reduced its expression dosage, and produced all flesh fruit tomato.

plant biology↗

Evidence for nutrient-dependent regulation of the COPII coat by O-GlcNAcylation

O-linked {beta}-N-acetylglucosamine (O-GlcNAc) is a dynamic form of intracellular glycosylation common in animals, plants and other organisms. O-GlcNAcylation is essential in mammalian cells and is dysregulated in myriad human diseases, such as cancer, neurodegeneration and metabolic syndrome. Despite this pathophysiological significance, key aspects of O-GlcNAc signaling remain incompletely understood, including its impact on fundamental cell biological processes. Here, we investigate the role of O-GlcNAcylation in the coat protein II complex (COPII), a system universally conserved in eukaryotes that mediates anterograde vesicle trafficking from the endoplasmic reticulum. We identify new O-GlcNAcylation sites on Sec24C, Sec24D and Sec31A, core components of the COPII system, and provide evidence for potential nutrient-sensitive pathway regulation through site-specific glycosylation. Our work suggests a new connection between metabolism and trafficking through the conduit of COPII protein O-GlcNAcylation.

cell biology↗

The Phaeodactylum tricornutum Diaminopimelate Decarboxylase was Acquired via Horizontal Gene Transfer from Bacteria and Displays Substrate Promiscuity

Diatoms are predicted to synthesize certain amino acids within the chloroplast, including L-lysine via a diaminopimelate-dependent pathway. Herein, we report that the model diatom, Phaeodactylum tricornutum, possesses a chimeric lysine biosynthetic pathway, which coalesces bacterial and plant genes, and is terminated by a chloroplast-localized diaminopimelate decarboxylase (DAPDC, PtLYSA). We show that while RNAi ablation of PtLYSA is either synthetically lethal or concomitant with a slower growth rate, Cas9-mediated mutagenesis of PtLYSA results in recovery of heterozygous cells lines, suggesting that PtLYSA is an essential gene. Previously characterized DAPDCs are unique within the PLP-dependent decarboxylases where catalysis occurs at the D-stereocenter of the substrate and display a strict stereochemical preference for a (D,L)- or meso-substrate and not the D,D- or L,L-isomers of diaminopimelate (DAP) to synthesize L-lysine. Using decarboxylation assays and differential scanning calorimetry analyses, we validate that PtLYSA is a bona fide DAPDC and uncover its unexpected stereopromiscuous behavior in substrate specificity. The crystal structure of PtLYSA confirms the enzyme is an obligate homodimer in which both protomers reciprocally participate in the active site. The structure underscores features unique to the PtLYSA clan of DAPDC and provides structural insight into the determinants responsible for the substrate-promiscuity observed in PtLYSA.

biochemistry↗

Essential gene analysis in Acinetobacter baumannii by high-density transposon mutagenesis and CRISPR interference

Acinetobacter baumannii is a poorly understood bacterium capable of life-threatening infections in hospitals. Few antibiotics remain effective against this highly resistant pathogen. Developing rationally-designed antimicrobials that can target A. baumannii requires improved knowledge of the proteins that carry out essential processes allowing growth of the organism. Unfortunately, studying essential genes has been challenging using traditional techniques, which usually require time-consuming recombination-based genetic manipulations. Here, we performed saturating mutagenesis with dual transposon systems to identify essential genes in A. baumannii and we developed a CRISPR-interference (CRISPRi) system for facile analysis of these genes. We show that the CRISPRi system enables efficient transcriptional silencing in A. baumannii. Using these tools, we confirmed the essentiality of the novel cell division protein AdvA and discovered a previously uncharacterized AraC-family transcription factor (ACX60_RS03245) that is necessary for growth. In addition, we show that capsule biosynthesis is a conditionally essential process, with mutations in late-acting steps causing toxicity in strain ATCC 17978 that can be bypassed by blocking early-acting steps or activating the BfmRS stress response. These results open new avenues for analysis of essential pathways in A. baumannii. ImportanceNew approaches are urgently needed to control A. baumannii, one of the most drug resistant pathogens known. To facilitate the development of novel targets that allow inhibition of the pathogen, we performed a large-scale identification of genes whose products the bacterium needs for growth. We also developed a CRISPR-based gene knockdown tool that operates efficiently in A. baumannii, allowing rapid analysis of these essential genes. We used these methods to define multiple processes vital to the bacterium, including a previously uncharacterized gene-regulatory factor and export of a protective polymeric capsule. These tools will enhance our ability to investigate processes critical for the essential biology of this challenging hospital-acquired pathogen.

microbiology↗

BioContainers Registry: searching for bioinformatics tools, packages and containers

1BioContainers is an open-source project that aims to create, store, and distribute bioinformatics software containers and packages. The BioContainers community has developed a set of guidelines to standardize the software containers including the metadata, versions, licenses, and/or software dependencies. BioContainers supports multiple packaging and containers technologies such as Conda, Docker, and Singularity. Here, we introduce the BioContainers Registry and Restful API to make containerized bioinformatics tools more findable, accessible, interoperable, and reusable (FAIR). BioContainers registry provides a fast and convenient way to find and retrieve bioinformatics tools packages and containers. By doing so, it will increase the use of bioinformatics packages and containers while promoting replicability and reproducibility in research.

bioinformatics↗

Dynamic Mechanical Cue Facilitate Collective Responses of Crowded Cell Population

Collective cell behavior is essential for tissue growth, development and function, e.g. heartbeat1, immune responses2 and cerebral consciousness3. In recent years, studies on population cells uncover that collective behavior emerges in both inter- and intra-cellular activities, e.g. synchronized signal cascade4, and collective migration5. As the movement and shape transition of cells within the crowded environment of biological tissue can generate mechanical cues at the cell-cell interface, which may affect the signaling cascade6,7, we suspect that the inter- and intra-cellular collective behavior interplay with one another and cooperatively regulate life machinery. To verify our hypothesis, we study the collective responses of fibroblasts in a confluent cell monolayer (CCM). Our results demonstrate that cells in CCM show distinctive behavior as compared to the stand-alone (SA) cells, suggesting effect of inter-cellular interactions. Upon periodic TNF- stimulation, collective behavior emerges simultaneously in NF-{kappa}B signaling cascade and nuclear shape fluctuations in CCM but not SA cells. We then model the inter-cellular interactions in CCM using a customized microfluidic device, and discover a feedback loop intrinsic to CCM, in which dynamic mechanical cues and mechano-signaling act as link connecting the inter- and intra-cellular collective activities. We found that mechano-signaling triggered by the dynamic mechanical cues causes collective nuclear shape fluctuation (NSF), which subsequently facilitates the collective behavior in NF-{kappa}B dynamics. Furthermore, our studies reveal that regardless of the input TNF- periodicity, cellular responses of single fibroblasts are elevated when the dynamic mechanical cues synergize with the chemical inputs, and inhibited when there is phase-mismatching. We, therefore, postulate that besides the biological significance of mechano-signaling in regulating collective cell responses, the induction of dynamic mechanical cues to human body may be a potential therapeutic approach, allowing us to regulate the action of single cells to achieve optimal tissue performance.

biophysics↗

Optimized photochemistry and enzymology enable efficient analysis of RNA structures and interactions in cells and virus infections

Direct determination of RNA structures and interactions in living cells is critical for understanding their functions. Current crosslinking and proximity-ligation approaches are fundamentally limited due to inefficient RNA crosslinking, purification and high-level photochemical damages. Here we present PARIS2 (psoralen analysis of RNA interactions and structures, second generation), a re-invented method for capturing RNA duplexes in cells with three orders of magnitude improved efficiency. PARIS2 captures ribosome small subunit (SSU) binding sites on mRNAs, reporting translation status on a transcriptome wide scale, and captures spliceosomal snRNP binding sites on various RNA targets. We determine the RNA genome structure of enterovirus D68, a re-emerging viral pathogen associated with severe neurological symptoms, and discover alternative conformations in the internal ribosome entry site (IRES) that controls translation initiation. Together, these results reveal new aspects of RNA photochemistry and enzymology, and enable highly efficient interrogation of the RNA structurome and interactome in cells.

genomics↗

Repairing neural damage in a C. elegans chemosensory circuit using genetically engineered synapses

Neuronal loss can considerably diminish neural circuit function, impairing normal behavior by disrupting information flow in the circuit. We reasoned that by rerouting the flow of information in the damaged circuit it may be possible to offset these negative outcomes. We examined this possibility using the well-characterized chemosensory circuit of the nematode worm C. elegans. In this circuit, a main sensory neuron class sends parallel outputs to several interneuron classes. We found that the removal of one of these interneuron classes impairs chemotaxis to attractive odors, revealing a prominent path for information flow in the circuit. To alleviate these deficiencies, we sought to reinforce a remaining neural pathway. We used genetically engineered electrical synapses for this purpose, and observed the successful recovery of chemotaxis performance. However, we were surprised to find that the recovery was largely mediated by inadvertently formed left-right lateral electrical connections within individual neuron classes. Our analysis suggests that these additional electrical synapses help restore circuit function by amplifying weakened neuronal signals in the damaged circuit. These results demonstrate the power of genetically engineered synapses to regulate information flow and signal intensity in damaged neural circuits.

neuroscience↗

Click-ExM enables expansion microscopy for all biomolecules

Expansion microscopy (ExM) allows super-resolution imaging on conventional fluorescence microscopes, but has been limited to proteins and nucleic acids. Here we develop click-ExM, which integrates click-labeling into ExM to enable a "one-stop-shop" method for nanoscale imaging of various types of biomolecules. Using 18 clickable labels for click-ExM imaging of DNA, RNA, proteins, lipids, glycans and small molecules, we demonstrate its universality, compatibility with signal-amplification techniques, and broad applications in cellular imaging.

bioengineering↗

Excessive Polyamine Generation in Keratinocytes Promotes Self-RNA Endosomal Sensing by Dendritic Cells in Psoriasis

The mechanisms underlying tissue-specific chronic inflammation are elusive. Here we report that mice lacking Protein Phosphatase 6 in keratinocytes are predisposed to psoriasis-like skin inflammation, with an inordinate urea cycle and enhanced oxidative phosphorylation that supports hyperproliferation. This phenotype is mediated by increased Arginase-1 production resulting from CCAAT/enhancer-binding protein beta activation. Single-cell RNA-seq of the psoriatic epidermis revealed that the rate-limiting enzyme for Arginine biosynthesis, Argininosuccinate synthetase 1, maintains the Arginine pool, which is indispensable for immune responses. Accumulated polyamines branched from the urea cycle promote endosomal Tlr7-dependent self-RNA sensing by myeloid dendritic cells. This process is achieved with the assistance of an RNA-binding peptide that originates from the heterogeneous nuclear ribonucleoprotein A1, a probable autoantigen in psoriasis. Finally, targeting urea cycle wiring with an arginase inhibitor markedly improved skin inflammation in murine and non-human primate models of psoriasis. Our findings suggest that urea cycle alteration and excessive polyamine production by psoriatic keratinocytes promote self-RNA sensing by dendritic cells, which links the hyperproliferation of stationary cells with innate-immune activation in an auto-inflammatory condition.

immunology↗

Common postzygotic mutational signature in multiple healthy adult tissues related to embryonic hypoxia

Postzygotic mutations are acquired in all of the normal tissues throughout an individuals lifetime and hold clues for identifying mutagenesis causing factors. The process and underlying mechanism of postzygotic mutations in normal tissues is still poorly understood. In this study, we investigated postzygotic mutation spectra in healthy individuals by optimized ultra-deep exome sequencing of time series samples from the same volunteer and samples from different individuals. In cells of blood, sperm, and muscle, we resolved three common types of mutational signature. Two of them are known to represent clock-like mutational processes, and their proportions in mutation profiles associated with polymorphisms of epigenetic regulation genes, suggesting the contribution of personal genetic backgrounds to underlying biological process. Notably, the third signature, characterized by C>T transitions at GpCpN sites, tends to be a feature of diverse normal tissues. Mutations of this type were likely to occur early in embryo development even before the tissue differentiation, as indicated by their relatively high allele frequencies, sharing variants between multiple tissues, and lacking of age-related accumulation. Almost all tumors shown in public datasets did not have this signature detected except for 19.6% of clear cell renal cell carcinoma samples, which featured by activation of the hypoxia-induced signaling pathway. Moreover, in vitro activation of HIF signaling pathway successfully introduced the corresponding mutation profile of this signature in a culture-expanded human embryonic stem cell line. Therefore, embryonic hypoxia may explain this novel signature across multiple normal tissues. Our study suggest hypoxic conditions in the early stage of embryo development may be a crucial factor for the C>T transitions at GpCpN sites and individual genetic background also related to shaping human postzygotic mutation profiles.

genetics↗

Calcium induced calcium release in proximity to hair cell BK channels revealed by PKA activation

Large conductance calcium-activated potassium (BK) channels play a critical role in electrical resonance, a mechanism of frequency selectivity in chicken hair cells. We determine that BK currents are dependent on inward flow of Ca2+, and intracellular buffering of Ca2+. Entry of Ca2+ is further amplified locally by Ca2+ induced Ca2+ release (CICR) in close proximity to plasma membrane BK channels. Ca2+ imaging reveals peripheral clusters of high concentrations of Ca2+ that are suprathreshold to that needed to activate BK channels. PKA activation increases BK currents likely by recruiting more BK channels due to spatial spread of high Ca2+ concentrations in turn from increasing CICR. STORM imaging confirms the presence of nanodomains with ryanodine and IP3 receptors in close proximity to the Slo subunit of BK channels. Together, these data require a rethinking of how electrical resonance is brought about and suggest effects of CICR in synaptic release. Both genders were included in this study.

physiology↗

Expression, Purification, and Functional Reconstitution of 19F-labeled Cytochrome b5 in Peptide Nanodiscs for NMR Studies

Microsomal cytochrome b5 (cytb5) is a membrane-bound protein capable of donating the second electron to cytochrome P450s (CYP P450s) in the CYP P450s monooxygenase reactions. Recent studies have demonstrated the importance of the transmembrane domain of cytb5 in the interaction with cytP450 by stabilizing its monomeric structure. While recent NMR studies have provided high-resolution insights into the structural interactions between the soluble domains of ~16-kDa cytb5 and ~57-kDa cytP450 in a membrane environment, there is need for studies to probe the residues in the transmembrane region as well as to obtain intermolecular distance constraints to better understand the very large size cytb5-cytP450 complex structure in a near native membrane environment. In this study, we report the expression, purification, functional reconstitution of 19F-labeled full-length rabbit cytb5 in peptide based nanodiscs for structural studies using NMR spectroscopy. Size exclusion chromatography, dynamic light scattering, transmission electron microscopy, and NMR experiments show a stable reconstitution of cytb5 in 4F peptide-based lipid-nanodiscs. Our results demonstrate that the use of peptide-nanodiscs containing cytb5 19F-labeled with 5-fluorotryptophan (5FW) enables, for the first time, the detection of residues from the transmembrane domain in different lipid compositions by solution 19F NMR experiments. 19F NMR results revealing the interaction of the transmembrane domain of cytb5 with the full-length rabbit Cytochrome P450 2B4 (CYP2B4) are also presented. We expect the results presented in this study to be useful to devise approaches to probe the structure, dynamics and functional roles of transmembrane domains of a membrane protein, and also to measure intermolecular 19F-19F distance constraints to determine the structural interactions between the transmembrane domains.

biochemistry↗

A mechanism coordinating root elongation, endodermal differentiation, redox homeostasis and response

Root growth relies on both cell division and elongation, which occur in the meristem and elongation zones respectively. SCARECROW (SCR) is a GRAS family gene essential for root growth and radial patterning in the Arabidopsis root. Previous studies showed that SCR promotes root growth by suppressing cytokinin response in the meristem, but there is also evidence that SCR expressed beyond the meristem is required as well for root growth. Here we report that SCR promotes root growth by promoting cell elongation through suppression of oxidative stress response and maintenance of redox homeostasis in the elongation zone. In the scr root, a higher level of hydrogen peroxide was detected, which can be attributed to down-regulation of peroxidase gene 3. When stress response was blocked or redox status was ameliorated by the aba2 or upb1 mutation, the scr mutant produced a significantly longer root with longer cells and a larger and mitotically more active meristem, even though the stem cell and radial patterning defects still persisted. We showed that WRKY15, an oxidative responsive gene, was a direct target of SCR down-regulated in the scr mutant, which suggests that SCR has an active role in suppressing oxidative stress response. Since hydrogen peroxide and peroxidases are essential for endodermal differentiation, these results suggest that SCR plays a central role in coordinating cell elongation, endodermal differentiation, redox homeostasis, and oxidative stress response in plant root.\n\nOne sentence summaryThis study reveals a novel mechanism of root growth regulation, which involves a previously unrecognized role of SCR in regulating cell elongation, endodermal differentiation, and redox homeostasis.

plant biology↗

Cas12a-based on-site and rapid nucleic acid detection of African swine fever

The mortality rate of hemorrhagic African swine fever (ASF), which targets domestic pigs and is caused by African swine fever virus (ASFV), can reach 100%. ASF has been reported in 25 Chinese provinces since August 2018. There is no effective treatment or vaccine for it and the present molecular diagnosis technologies have trade-offs in sensitivity, specificity, cost and speed, and none of them cater perfectly to ASF control. Thus, a technology that overcomes the need for laboratory facilities, is relatively low cost, and rapidly and sensitively detects ASFV would be highly valuable. Here, we describe an RAA-Cas12a-based system that combines recombinase-aided amplification (RAA) and CRISPR/Cas12a for ASFV detection. The fluorescence intensity readout of this system detected ASFV p72 gene levels as low as 10 aM. For on-site ASFV detection, lateral-flow strip readout was introduced for the first time in the RAA-Cas12a based system (named CORDS, Cas12a-based On-site and Rapid Detection System). We used CORDS to detect target DNA highly specifically using the lateral-flow strip readout. CORDS could identify the p72 gene at femtomolar sensitivity in an hour at 37{degrees}C, and only requires an incubator. For ease of use, the regents of CORDS was lyophilized to three tubes and remained the same sensitivity when stored at 4 {degrees}C for at least 7 days. Thus, CORDS provides a rapid, sensitive and easily operable method for ASFV on-site detection. Lyophilized CORDS can withstand long-term transportation and storage, and is ready for field applications.

molecular biology↗

INX-18 and INX-19 play distinct roles in electrical synapses that modulate aversive behavior in Caenorhabditis elegans

In order to respond to changing environments and fluctuations in internal states, animals adjust their behavior through diverse neuromodulatory mechanisms. In this study we show that electrical synapses between the ASH primary quinine-detecting sensory neurons and the neighboring ASK neurons are required for modulating the aversive response to the bitter tastant quinine in C. elegans. Mutant worms that lack the electrical synapse proteins INX-18 and INX-19 become hypersensitive to dilute quinine. Cell-specific rescue experiments indicate that inx-18 operates in ASK while inx-19 is required in both ASK and ASH for proper quinine sensitivity. Imaging analyses find that INX-19 in ASK and ASH localizes to the same regions in the nerve ring, suggesting that both sides of ASK-ASH electrical synapses contain INX-19. While inx-18 and inx-19 mutant animals have a similar behavioral phenotype, several lines of evidence suggest the proteins encoded by these genes play different roles in modulating the aversive quinine response. First, INX-18 and INX-19 localize to different regions of the nerve ring, indicating that they are not present in the same synapses. Second, removing inx-18 disrupts the distribution of INX-19, while removing inx-19 does not alter INX-18 localization. Finally, by using a fluorescent cGMP reporter, we find that INX-18 and INX-19 have distinct roles in establishing cGMP levels in ASK and ASH. Together, these results demonstrate that electrical synapses containing INX-18 and INX-19 facilitate modulation of ASH nociceptive signaling. Our findings support the idea that a network of electrical synapses mediates cGMP exchange between neurons, enabling modulation of sensory responses and behavior.\n\nAuthor SummaryAnimals are constantly adjusting their behavior to respond to changes in the environment or to their internal state. This behavior modulation is achieved by altering the activity of neurons and circuits through a variety of neuroplasticity mechanisms. Chemical synapses are known to impact neuroplasticity in several different ways, but the diversity of mechanisms by which electrical synapses contribute is still being investigated. Electrical synapses are specialized sites of connection between neurons where ions and small signaling molecules can pass directly from one cell to the next. By passing small molecules through electrical synapses, neurons may be able to modify the activity of their neighbors. In this study we identify two genes that contribute to electrical synapses between two sensory neurons in C. elegans. We show that these electrical synapses are crucial for proper modulation of sensory responses, as without them animals are overly responsive to an aversive stimulus. In addition to pinpointing their sites of action, we present evidence that they may be contributing to neuromodulation by facilitating passage of the small molecule cGMP between neurons. Our work provides evidence for a role of electrical synapses in regulating animal behavior.

neuroscience↗

Drought Resistance of 10 Ground Cover Seedling Species during Roof Greening

10 species drought resistance cases have been studied, including Paeonia lactiflora, Hemerocallis dumortieri, Physostegia virginiana, Iris lacteal, Hylotelephium erythrostictum, Sedum lineare, Iris germanica, Cosmos bipinnata, Hosta plantaginea and Dianthus barbatus. By researching these drought resistance cases, a suggestion can be given for roof greening. This research sets 3 drought stress scenarios by controlling the soil relative water content (RWC), including moderately drought stress (40%{+/-}2% < RWC < 45%{+/-}2%), strong drought stress (RWC < 30%{+/-}2%) and control group (RWC > 75%{+/-}2%). After the seedlings survived the drought stress, the damaging rate of permeability (DRP), total chlorophylls concentrations (Chl), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (AsAPOD) of seedlings will be measured. Finally, a subordinate function method was applied to assess these species drought resistance. Cosmos bipinnata and Physostegia virginiana was dead after having suffered with moderately drought stress and strong drought stress, respectively. Although other species survived, the individual variation was huge especially for physiological and biochemical index. Hemerocallis dumortieri, Iris lactea and Hosta plantagineas DRP had little change when they lived in the normal water condition and suffered with drought stress. Most of the species (except Paeonia lactiflora and Sedum lineare) showed a lower SOD activity during moderately drought stress compared with the sufficient soil water condition and strong drought stress condition. The changes of plants POD activity and AsAPOD activity are very similar: when drought stress enhanced, the activity of protect enzyme reduced. According to the subordinate function method, the order of plants resistance to the drought is as follow: Hosta plantaginea > Sedum lineare > Iris germanica > Hemerocallis dumortieri > Iris lactea >Hylotelephium erythrostictum > Dianthus barbatus > Paeonia lactiflora > Physostegia virginiana > Cosmos bipinnata.

ecology↗