Glutathionylation of a glycolytic enzyme promotes cell death and vigor loss during aging of elm seeds.

Seed deterioration during storage is a major problem in agricultural and forestry production and for germplasm conservation. Our previous studies have shown that a mitochondrial outer membrane protein VOLTAGE-DEPENDENT ANION CHANNEL (VDAC) is involved in programmed cell death (PCD)-like viability loss during the controlled deterioration treatment (CDT) of elm (Ulmus pumila L.) seeds, but its underlying mechanism remains unclear. In this study, we demonstrate that the oxidative modification of GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPDH) is functioned in the gate regulation of VDAC during the CDT of elm seeds. Through biochemical and cytological methods and observations of transgenic material [Arabidopsis (Arabidopsis thaliana), Nicotiana benthamiana, and yeast (Saccharomyces cerevisiae)], we demonstrate that cysteine S-glutathionylated UpGAPDH1 interacts with UpVDAC3 during seed aging, which leads to a mitochondrial permeability transition and aggravation of cell death, as indicated by the leakage of the mitochondrial pro-apoptotic factor cytochrome c and the emergence of apoptotic nucleus. Physiological assays and inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that GAPDH glutathionylation is mediated by increased glutathione, which might be caused by increases in the concentrations of free metals, especially Zn. Introduction of the Zn-specific chelator TPEN [(N, N, N', N'-Tetrakis (2-pyridylmethyl)ethylenediamine)] significantly delayed seed aging. We conclude that glutathionylated UpGAPDH1 interacts with UpVDAC3 and serves as a pro-apoptotic protein for VDAC-gating regulation and cell death initiation during seed aging.

HiCube: interactive visualization of multiscale and multimodal Hi-C and 3D genome data.

SUMMARY: HiCube is a lightweight web application for interactive visualization and exploration of diverse types of genomics data at multiscale resolutions. Especially, HiCube displays synchronized views of Hi-C contact maps and 3D genome structures with user-friendly annotation and configuration tools, thereby facilitating the study of 3D genome organization and function. AVAILABILITY AND IMPLEMENTATION: HiCube is implemented in Javascript and can be installed via NPM. The source code is freely available at GitHub (https://github.com/wmalab/HiCube).

Tulip transcription factor TgWRKY75 activates salicylic acid and abscisic acid biosynthesis to synergistically promote petal senescence.

WRKY transcription factors play a central role in controlling plant organ senescence; however, it is unclear whether and how they regulate petal senescence in the widely grown ornamental plant tulip (Tulipa gesneriana). In this study, we report that TgWRKY75 promotes petal senescence by enhancing the synthesis of both abscisic acid (ABA) and salicylic acid (SA) in tulip and in transgenic Arabidopsis. The expression level of TgWRKY75 was up-regulated in senescent petals, and exogenous ABA or SA treatment induced its expression. The endogenous contents of ABA and SA significantly increased during petal senescence and in response to TgWRKY75 overexpression. Two SA synthesis-related genes, TgICS1 and TgPAL1, were identified as direct targets of TgWRKY75, which binds to their promoters. In parallel, TgWRKY75 activated the expression of the ABA biosynthesis-related gene TgNCED3 via directly binding to its promoter region. Site mutation of the W-box core motif located in the promoters of TgICS1, TgPAL1, and TgNCED3 eliminated their interactions with TgWRKY75. In summary, our study demonstrates a dual regulation of ABA and SA biosynthesis by TgWRKY75, revealing a synergistic process of tulip petal senescence through feedback regulation between TgWRKY75 and the accumulation of ABA and SA.

Docetaxel liposomes for lung targeted delivery: development and evaluation.

Docetaxel (DTX) is an artificial semi-synthetic second-generation taxane anti-tumor drug, which is suitable for the treatment of various cancers such as lung cancer. The route of administration of DTX formulations has been extended to oral, intravenous, and rectal, with few studies on pulmonary administration being reported. Here, we had developed DTX liposomes (DTX-lips) for pulmonary inhalation administration. The particle size of the preparation was 125 nm, the encapsulation efficiency was 94.4 ± 0.14%, and the drug loading capacity was 1.26 ± 0.01%. It had good stability. The fine particle fraction with aerodynamic diameter less than 6.4 µm accounts for 64.63 ± 0.12%, showed excellent aerosolization performance. DTX-lips were slow to release in simulated lung fluid. The fluorescence distribution experimented in mice and tissues showed that the fluorescence of the inhaled liposome group was mainly distributed in the lung, and the retention time was significantly prolonged as compared with those of the other two groups. No significant fluorescence was observed in other tissues, which was conducive to the full effect of the drug in the lung tissue. DTX-lips had no damage to respiratory system and whole body. These results indicated that the inhaled DTX-lips had good lung targeting, reduced accumulation in other organs, and improved the safety and effectiveness of the drug.

Menthol nanoliposomes enhanced anti-tumor immunotherapy by increasing lymph node homing of dendritic cell vaccines.

Menthol, a cyclic terpene alcohol, plays a critical role in overcoming the blood-brain barrier and stratum corneum barrier. Herein, we innovatively propose a menthol nanoliposome (Men-nanoLips) that can dramatically increase lymph node accumulation of the dendritic cell (DC)-based anti-tumor vaccines. Specifically, Men-nanoLips efficiently enhanced lymphatic endothelial cell (EC) barrier permeability by reducing the expression of tight junction proteins. And interestingly, Men-nanoLips not only up-regulated the expression of CCR7 in DCs but also increased the secretion of CCL21 in lymphatic ECs. Moreover, Men-nanoLips promoted DC vaccine maturation as evidenced by increasing the expression of costimulatory molecules and up-regulating the pseudopodia-like protein. With those complementary mechanisms provided by Men-nanoLips, the number of the B16 whole-tumor cell lysate-loaded DCs that target the draining LN enhanced remarkably and significantly boosted the treatment efficacy of DC anti-tumor vaccines. Therefore, we concluded that Men-nanoLips could be instructive for increasing LN homing of DC vaccines.

Ultrasensitive Determination of Sugar Phosphates in Trace Samples by Stable Isotope Chemical Labeling Combined with RPLC-MS.

Sugar phosphates are important metabolic intermediates in organisms and play a vital role in energy and central carbon metabolism. Profiling of sugar phosphates is of great significance but full of challenges due to their high structural similarity and low sensitivities in liquid chromatography (LC)-mass spectrometry (MS). In this study, we developed a novel stable isotope chemical labeling combined with the reversed-phase (RP)LC-MS method for ultrasensitive determination of sugar phosphates at the single-cell level. By chemical derivatization with 2-(diazo-methyl)-N-methyl-N-phenyl-benzamide (2-DMBA) and d5-2-DMBA, sugar phosphate isomers can obtain better separation and identification, and the detection sensitivities of sugar phosphates increased by 3.5-147 folds. The obtained limits of detection of sugar phosphates ranged from 5 to 16 pg/mL. Using this method, we achieved ultrasensitive and accurate quantification of 12 sugar phosphates in different trace biological samples. Benefiting from the improved separation and detection sensitivity, we successfully quantified five sugar phosphates (d-glucose 1-phosphate, d-mannose 6-phosphate, d-fructose 6-phosphate, d-glucose 6-phosphate, and seduheptulose 7-phosphate) in a single protoplast of Arabidopsis thaliana.

Cinnamoyl coA: NADP oxidoreductase-like 1 regulates abscisic acid response by modulating phaseic acid homeostasis in Arabidopsis thaliana.

Phaseic acid (PA), a main catabolite of abscisic acid (ABA), is structurally related to ABA and possesses ABA-like hormonal activity. However, the comprehensive metabolism pathway and roles of PA are not well understood. Here, using homologous alignment and expression pattern analysis, we identified in Arabidopsis the previously named CRL1 (Cinnamoyl coA: NADP oxidoreductase-like 1) as a PA reductase that catalyses PA to dihydrophaseic acid. The function of CRL1 and the potential role of PA were studied in transgenic CRL1 plants. Overexpression of CRL1 resulted in decreased ABA sensitivity in seed germination and attenuated drought tolerance. In contrast, increased ABA sensitivity and elevated drought tolerance was observed in down-regulated and loss-of-function crl1 mutants. Tyr162 in the conserved motif is the key residue in CRL1 to catalyse PA. Accelerated seed germination and earlier flowering phenotype were also observed in overexpressing lines, while retarded seed germination and delayed flowering occurred in crl1 mutants which accumulated more PA, but less dihydrophaseic acid than the wild type. This study demonstrates that PA plays diverse functions in drought tolerance, seed germination and flowering in an ABA-like manner, which may increase the adaptive plasticity of plants.

The phytomelatonin receptor PMTR1 regulates seed development and germination by modulating abscisic acid homeostasis in Arabidopsis thaliana.

Melatonin is known to involve multiple physiological actions in plants. Herein, we found that exogenous melatonin inhibited the Arabidopsis seedling growth through the elevated abscisic acid (ABA) levels, and the elevated ABA was ascribed to the upregulation of 9-cis-epoxycarotenoid dioxygenase genes (NCEDs) in the ABA biosynthesis pathway. We also found that the overexpression lines of the melatonin receptor gene PMTR1 (also known as Cand2) yielded smaller seeds and germinated slower than the wild type, whereas PMTR1-knockout mutants produced larger seeds and germinated faster than the wild type. During the seed development, the accumulation peak of ABA was higher in the PMTR1-knockout mutant, while it was lower in the PMTR1-overexpression line than that in the wild type. In the dry seeds and imbibed seeds, the PMTR1-overexpression line accumulated higher ABA levels, while the PMTR1-knockout contained less ABA than the wild type. In summary, our findings suggest that PMTR1 is involved in ABA-mediated seed development and germination in Arabidopsis.

ASHIC: hierarchical Bayesian modeling of diploid chromatin contacts and structures.

The recently developed Hi-C technique has been widely applied to map genome-wide chromatin interactions. However, current methods for analyzing diploid Hi-C data cannot fully distinguish between homologous chromosomes. Consequently, the existing diploid Hi-C analyses are based on sparse and inaccurate allele-specific contact matrices, which might lead to incorrect modeling of diploid genome architecture. Here we present ASHIC, a hierarchical Bayesian framework to model allele-specific chromatin organizations in diploid genomes. We developed two models under the Bayesian framework: the Poisson-multinomial (ASHIC-PM) model and the zero-inflated Poisson-multinomial (ASHIC-ZIPM) model. The proposed ASHIC methods impute allele-specific contact maps from diploid Hi-C data and simultaneously infer allelic 3D structures. Through simulation studies, we demonstrated that ASHIC methods outperformed existing approaches, especially under low coverage and low SNP density conditions. Additionally, in the analyses of diploid Hi-C datasets in mouse and human, our ASHIC-ZIPM method produced fine-resolution diploid chromatin maps and 3D structures and provided insights into the allelic chromatin organizations and functions. To summarize, our work provides a statistically rigorous framework for investigating fine-scale allele-specific chromatin conformations. The ASHIC software is publicly available at https://github.com/wmalab/ASHIC.

Effects of extreme precipitation on hospital visit risk and disease burden of depression in Suzhou, China.

BACKGROUND: The purpose of this study was to explore the impact of extreme precipitation on the risk of outpatient visits for depression and to further explore its associated disease burden and vulnerable population. METHODS: A quasi-Poisson generalized linear regression model combined with distributed lag non-linear model (DLNM) was used to investigate the exposure-lag-response relationship between extreme precipitation (≥95th percentile) and depression outpatient visits from 2017 to 2019 in Suzhou city, Anhui Province, China. RESULTS: Extreme precipitation was positively associated with the outpatient visits for depression. The effects of extreme precipitation on depression firstly appeared at lag4 [relative risk (RR): 1.047, 95% confidence interval (CI): 1.005-1.091] and lasted until lag7 (RR = 1.047, 95% CI: 1.009-1.087). Females, patients aged ≥65 years and patients with multiple outpatient visits appeared to be more sensitive to extreme precipitation. The attributable fraction (AF) and numbers (AN) of extreme precipitation on outpatient visits for depression were 5.00% (95% CI: 1.02-8.82%) and 1318.25, respectively. CONCLUSIONS: Our findings suggested that extreme precipitation may increase the risk of outpatient visits for depression. Further studies on the burden of depression found that females, aged ≥65 years, and patients with multiple visits were priority targets for future warnings. Active intervention measures against extreme precipitation events should be taken to reduce the risk of depression outpatient visits.

Estimation of Soil Salt Content and Organic Matter on Arable Land in the Yellow River Delta by Combining UAV Hyperspectral and Landsat-8 Multispectral Imagery.

Rapid and large-scale estimation of soil salt content (SSC) and organic matter (SOM) using multi-source remote sensing is of great significance for the real-time monitoring of arable land quality. In this study, we simultaneously predicted SSC and SOM on arable land in the Yellow River Delta (YRD), based on ground measurement data, unmanned aerial vehicle (UAV) hyperspectral imagery, and Landsat-8 multispectral imagery. The reflectance averaging method was used to resample UAV hyperspectra to simulate the Landsat-8 OLI data (referred to as fitted multispectra). Correlation analyses and the multiple regression method were used to construct SSC and SOM hyperspectral/fitted multispectral estimation models. Then, the best SSC and SOM fitted multispectral estimation models based on UAV images were applied to a reflectance-corrected Landsat-8 image, and SSC and SOM distributions were obtained for the YRD. The estimation results revealed that moderately salinized arable land accounted for the largest proportion of area in the YRD (48.44%), with the SOM of most arable land (60.31%) at medium or lower levels. A significant negative spatial correlation was detected between SSC and SOM in most regions. This study integrates the advantages of UAV hyperspectral and satellite multispectral data, thereby realizing rapid and accurate estimation of SSC and SOM for a large-scale area, which is of great significance for the targeted improvement of arable land in the YRD.

Boron Isotope Tag-Assisted Ultrahigh-Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry for Discovery and Annotation of cis-Diol-Containing Metabolites.

cis-Diol-containing metabolites are widely distributed in living organisms, and they participate in the regulation of various important biological activities. The profiling of cis-diol-containing metabolites could help us in fully understanding their functions. In this work, based on the characteristic isotope pattern of boron, we employed a boronic acid reagent as the isotope tag to establish a sensitive and selective liquid chromatography-high-resolution mass spectrometry method for the screening and annotation of cis-diol-containing metabolites in biological samples. Boronic acid reagent 2-methyl-4-phenylaminomethylphenylboronic acid was used to label the cis-diol-containing metabolites in biological samples to improve the selectivity and MS sensitivity of cis-diol-containing metabolites. Based on the characteristic 0.996 Da mass difference of precursor ions and the peak intensity ratio of 1:4 originating from 10B and 11B natural isotopes, the potential cis-diol-containing metabolites were rapidly screened from biological samples. Potential cis-diol-containing metabolites were annotated by database searching and analysis of fragmentation patterns obtained by multistage MS (MSn) via collision-induced dissociation. Importantly, the cis-diol position could be readily resolved by the MS3 spectrum. With this method, a total of 45 cis-diol-containing metabolites were discovered in rice, including monoglycerides, polyhydroxy fatty acids, fatty alcohols, and so forth. Furthermore, the established method showed superiority in avoiding false-positive results in profiling cis-diol-containing metabolites.

Chemical Tagging Assisted Mass Spectrometry Analysis Enables Sensitive Determination of Phosphorylated Compounds in a Single Cell.

Polar phosphorylated metabolites are involved in a variety of biological processes and play vital roles in energetic metabolism, cofactor regeneration, and nucleic acid synthesis. However, it is often challenging to interrogate polar phosphorylated metabolites and compounds from biological samples. Liquid chromatography-mass spectrometry (LC/MS) now plays a central role in metabolomic studies. However, LC/MS-based approaches have been hampered by the issues of the low ionization efficiencies, low in vivo concentrations, and less chemical stability of polar phosphorylated metabolites. In this work, we synthesized paired reagents of light and heavy isotopomers, 2-(diazomethyl)phenyl)(9-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)methanone (DMPI) and d3-(2-(diazomethyl)phenyl)(9-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)methanone (d3-DMPI). The paired reagents of DMPI and d3-DMPI carry diazo groups that can efficiently and selectively react with the phosphate group on polar phosphorylated metabolites under mild conditions. As a proof of concept, we found that the transfer of the indole heterocycle group from DMPI/d3-DMPI to ribonucleotides led to the significant increase of ionization efficiencies of ribonucleotides during LC/MS analysis. The detection sensitivities of these ribonucleotides increased by 25-1137-fold upon DMPI tagging with the limits of detection (LODs) being between 7 and 150 amol. With the developed method, we achieved the determination of all the 12 ribonucleotides from a single mammalian cell and from a single stamen of Arabidopsis thaliana. The method provides a valuable tool to investigate the dynamic changes of polar phosphorylated metabolites in a single cell under particular conditions.

Characteristics and functions of glyceraldehyde 3-phosphate dehydrogenase S-nitrosylation during controlled aging of elm and Arabidopsis seeds.

Seed aging is the gradual decline in seed vigor, during which programmed cell death (PCD) occurs. The functions of nitric oxide (NO) are exerted through protein S-nitrosylation, a reversible post-translational modification. During seed aging, more than 80 proteins are S-nitrosylated, but the particular role of individual proteins is unknown. Here, we showed that the S-nitrosylation level of glyceraldehyde 3-phosphate dehydrogenase (UpGAPDH) in elm (Ulmus pumila L.) seeds increased after controlled deterioration treatment. UpGAPDH was S-nitrosylated at Cys154 during S-nitrosoglutathione (GSNO) treatment, and its oligomerization was triggered both in vitro and in elm seeds. Interestingly, UpGAPDH interacted with the mitochondrial voltage-dependent anion channel in an S-nitrosylation-dependent way. Some UpGAPDH-green fluorescent protein in Arabidopsis protoplasts co-localized with mitochondria during the GSNO treatment, while the S-nitrosylation-defective UpGAPDH C154S-GFP protein did not. Seeds of oxUpGAPDH lines showed cell death and lost seed vigor rapidly during controlled deterioration treatment-triggered seed aging, while those overexpressing S-nitrosylation-defective UpGAPDH-Cys154 did not. Our results suggest that S-nitrosylation of UpGAPDH may accelerate cell death and seed deterioration during controlled deterioration treatment. These results provide new insights into the effects of UpGAPDH S-nitrosylation on protein interactions and seed aging.

Physiological and metabolomic responses of bermudagrass (Cynodon dactylon) to alkali stress.

Bermudagrass (Cynodon dactylon) is a widely used warm-season turfgrass species with superior stress tolerance except for cold. In this study, a comparative analysis of the responses to alkali stress in bermudagrass at the physiological and metabolomic levels were performed. Mild alkali with relatively low pH slightly inhibited growth of bermudagrass as evidenced by lower electrolyte leakage, more rapid growth and higher survival rate when compared to moderate and severe alkali treatments. Moreover, the amount of 37 metabolites including amino acids, organic acids, sugars and sugar alcohols were modulated by the alkali treatments. Among them, 15 metabolites were involved in carbon and amino acid metabolic pathways. Under mild alkali stress, bermudagrass possibly slowed down metabolisms to maintain basic growth. However, moderate and severe alkali-stressed plants accumulated significantly higher amount of carbohydrates which might result in carbon starvation. Taken together, alkali stress had severely inhibitory effect partially due to combined ionic stress and high pH stress. These results suggested that bermudagrass employed different strategies in response to alkali stresses with different pH and ionic values.

N 6-Hydroxymethyladenine: a hydroxylation derivative of N6-methyladenine in genomic DNA of mammals.

In addition to DNA cytosine methylation (5-methyl-2'-deoxycytidine, m5dC), DNA adenine methylation (N6-methyl-2'-deoxyadenosine, m6dA) is another DNA modification that has been discovered in eukaryotes. Recent studies demonstrated that the content and distribution of m6dA in genomic DNA of vertebrates and mammals exhibit dynamic regulation, indicating m6dA may function as a potential epigenetic mark in DNA of eukaryotes besides m5dC. Whether m6dA undergoes the further oxidation in a similar way to m5dC remains elusive. Here, we reported the existence of a new DNA modification, N6-hydroxymethyl-2'-deoxyadenosine (hm6dA), in genomic DNA of mammalian cells and tissues. We found that hm6dA can be formed from the hydroxylation of m6dA by the Fe2+- and 2-oxoglutarate-dependent ALKBH1 protein in genomic DNA of mammals. In addition, the content of hm6dA exhibited significant increase in lung carcinoma tissues. The increased expression of ALKBH1 in lung carcinoma tissues may contribute to the increase of hm6dA in DNA. Taken together, our study reported the existence and formation of hm6dA in genomic DNA of mammals.

New Consideration of Herlyn-Werner-Wunderlich Syndrome Diagnosed by Ultrasound.

OBJECTIVES: As a rare malformation of the female reproductive system, Herlyn-Werner-Wunderlich syndrome (HWWS) was categorized into 3 classifications. It was recommended recently that, on the basis of the past classification, cervicovaginal atresia without communicating uteri should be newly added as classification 4. The surgical intervention will differ by type. To better optimize patient counseling as well as the preoperative evaluation and planning, our objective was to describe the ultrasound characteristics of each type of HWWS, including the new type. METHODS: From January 1995 to November 2015, 37 cases of HWWS in with complete ultrasound information confirmed by surgery in the Peking Union Medical College Hospital were reviewed. We analyzed their ultrasound features, including hematometra, hematocervix, hematocolpos, and an ovarian chocolate cyst. RESULTS: All of the ultrasound images of the 37 patients showed uterus didelphys with ipsilateral renal agenesis. Compared with the other 3 types, classification 4 showed distinctive ultrasound characteristics. Most cases of classification 4 showed hematometra (5 of 7 [71.4%]) and an ipsilateral ovarian chocolate cyst (6 of 7 [85.7%]), which was significantly higher than in the other 3. A rudimentary uterine horn was also a distinctive characteristic in this type. Meanwhile none of the classification 4 cases showed hematocervix or hydrocolpos, which were common signs of the other 3. CONCLUSIONS: According to this new classification criteria for HWWS, ultrasound characteristics of the new classification 4 differ from the others. As classification 4 was suggested to have a different surgical option, we should pay attention to its ultrasound characteristics, which might help in providing more information about the treatment and prognosis to the gynecologist.

Radiation Oncologists' Perceptions of Adopting an Artificial Intelligence-Assisted Contouring Technology: Model Development and Questionnaire Study.

BACKGROUND: An artificial intelligence (AI)-assisted contouring system benefits radiation oncologists by saving time and improving treatment accuracy. Yet, there is much hope and fear surrounding such technologies, and this fear can manifest as resistance from health care professionals, which can lead to the failure of AI projects. OBJECTIVE: The objective of this study was to develop and test a model for investigating the factors that drive radiation oncologists' acceptance of AI contouring technology in a Chinese context. METHODS: A model of AI-assisted contouring technology acceptance was developed based on the Unified Theory of Acceptance and Use of Technology (UTAUT) model by adding the variables of perceived risk and resistance that were proposed in this study. The model included 8 constructs with 29 questionnaire items. A total of 307 respondents completed the questionnaires. Structural equation modeling was conducted to evaluate the model's path effects, significance, and fitness. RESULTS: The overall fitness indices for the model were evaluated and showed that the model was a good fit to the data. Behavioral intention was significantly affected by performance expectancy (ß=.155; P=.01), social influence (ß=.365; P<.001), and facilitating conditions (ß=.459; P<.001). Effort expectancy (ß=.055; P=.45), perceived risk (ß=-.048; P=.35), and resistance bias (ß=-.020; P=.63) did not significantly affect behavioral intention. CONCLUSIONS: The physicians' overall perceptions of an AI-assisted technology for radiation contouring were high. Technology resistance among Chinese radiation oncologists was low and not related to behavioral intention. Not all of the factors in the Venkatesh UTAUT model applied to AI technology adoption among physicians in a Chinese context.

Phosphatidylinositol-specific phospholipase C2 functions in auxin-modulated root development.

Nine phosphatidylinositol-specific phospholipases C (PLCs) have been identified in the Arabidopsis genome; among the importance of PLC2 in reproductive development is significant. However, the role of PLC2 in vegetative development such as in root growth is elusive. Here, we report that plc2 mutants displayed multiple auxin-defective phenotypes in root development, including short primary root, impaired root gravitropism, and inhibited root hair growth. The DR5:GUS expression and the endogenous indole-3-acetic acid (IAA) content, as well as the responses of a set of auxin-related genes to exogenous IAA treatment, were all decreased in plc2 seedlings, suggesting the influence of PLC2 on auxin accumulation and signalling. The root elongation of plc2 mutants was less sensitive to the high concentration of exogenous auxins, and the application of 1-naphthaleneacetic acid or the auxin transport inhibitor N-1-naphthylphthalamic acid could rescue the root hair growth of plc2 mutants. In addition, the PIN2 polarity and cycling in plc2 root epidermis cells were altered. These results demonstrate a critical role of PLC2 in auxin-mediated root development in Arabidopsis, in which PLC2 influences the polar distribution of PIN2.