Publications by authors named "Zhaojun Ding"

71 Publications

Cell kinetics of auxin transport and activity in Arabidopsis root growth and skewing.

Nat Commun 2021 03 12;12(1):1657. Epub 2021 Mar 12.

School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel.

Auxin is a key regulator of plant growth and development. Local auxin biosynthesis and intercellular transport generates regional gradients in the root that are instructive for processes such as specification of developmental zones that maintain root growth and tropic responses. Here we present a toolbox to study auxin-mediated root development that features: (i) the ability to control auxin synthesis with high spatio-temporal resolution and (ii) single-cell nucleus tracking and morphokinetic analysis infrastructure. Integration of these two features enables cutting-edge analysis of root development at single-cell resolution based on morphokinetic parameters under normal growth conditions and during cell-type-specific induction of auxin biosynthesis. We show directional auxin flow in the root and refine the contributions of key players in this process. In addition, we determine the quantitative kinetics of Arabidopsis root meristem skewing, which depends on local auxin gradients but does not require PIN2 and AUX1 auxin transporter activities. Beyond the mechanistic insights into root development, the tools developed here will enable biologists to study kinetics and morphology of various critical processes at the single cell-level in whole organisms.
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http://dx.doi.org/10.1038/s41467-021-21802-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7954861PMC
March 2021

SIZ1 negatively regulates aluminum resistance by mediating the STOP1-ALMT1 pathway in Arabidopsis.

J Integr Plant Biol 2021 Mar 12. Epub 2021 Mar 12.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China.

Sensitive to proton rhizotoxicity 1 (STOP1) functions as a crucial regulator of root growth during aluminum (Al) stress. However, how this transcription factor is regulated by Al stress to affect downstream genes expression is not well understood. To explore the underlying mechanisms of the function and regulation of STOP1, we employed a yeast two hybrid screen to identify STOP1-interacting proteins. The SUMO E3 ligase SIZ1, was found to interact with STOP1 and mainly facilitate its SUMO modification at K40 and K212 residues. Simultaneous introduction of K40R and K212R substitutions in STOP1 enhances its transactivation activity to upregulate the expression of aluminum-activated malate transporter 1 (ALMT1) via increasing the association with mediator 16 (MED16) transcriptional co-activator. Loss of function of SIZ1 causes highly increased expression of ALMT1, thus enhancing Al-induced malate exudation and Al tolerance. Also, we found that the protein level of SIZ1 is reduced in response to Al stress. Genetic evidence demonstrates that STOP1/ALMT1 is epistatic to SIZ1 in regulating root growth response to Al stress. This study suggests a mechanism about how the SIZ1-STOP1-ALMT1 signaling module is involved in root growth response to Al stress.
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http://dx.doi.org/10.1111/jipb.13091DOI Listing
March 2021

Cell-type action specificity of auxin on Arabidopsis root growth.

Plant J 2021 May 3;106(4):928-941. Epub 2021 Apr 3.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China.

The plant hormone auxin plays a critical role in root growth and development; however, the contributions or specific roles of cell-type auxin signals in root growth and development are not well understood. Here, we mapped tissue and cell types that are important for auxin-mediated root growth and development by manipulating the local response and synthesis of auxin. Repressing auxin signaling in the epidermis, cortex, endodermis, pericycle or stele strongly inhibited root growth, with the largest effect observed in the endodermis. Enhancing auxin signaling in the epidermis, cortex, endodermis, pericycle or stele also caused reduced root growth, albeit to a lesser extent. Moreover, we established that root growth was inhibited by enhancement of auxin synthesis in specific cell types of the epidermis, cortex and endodermis, whereas increased auxin synthesis in the pericycle and stele had only minor effects on root growth. Our study thus establishes an association between cellular identity and cell type-specific auxin signaling that guides root growth and development.
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http://dx.doi.org/10.1111/tpj.15208DOI Listing
May 2021

MPK14-mediated auxin signaling controls lateral root development via ERF13-regulated very-long-chain fatty acid biosynthesis.

Mol Plant 2021 02 19;14(2):285-297. Epub 2020 Nov 19.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China. Electronic address:

Auxin plays a critical role in lateral root (LR) formation. The signaling module composed of auxin-response factors (ARFs) and lateral organ boundaries domain transcription factors mediates auxin signaling to control almost every stage of LR development. Here, we show that auxin-induced degradation of the APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription factor ERF13, dependent on MITOGEN-ACTIVATED PROTEIN KINASE MPK14-mediated phosphorylation, plays an essential role in LR development. Overexpression of ERF13 results in restricted passage of the LR primordia through the endodermal layer, greatly reducing LR emergence, whereas the erf13 mutants showed an increase in emerged LR. ERF13 inhibits the expression of 3-ketoacyl-CoA synthase16 (KCS16), which encodes a fatty acid elongase involved in very-long-chain fatty acid (VLCFA) biosynthesis. Overexpression of KCS16 or exogenous VLCFA treatment rescues the LR emergence defects in ERF13 overexpression lines, indicating a role downstream of the auxin-MPK14-ERF13 signaling module. Collectively, our study uncovers a novel molecular mechanism by which MPK14-mediated auxin signaling modulates LR development via ERF13-regulated VLCFA biosynthesis.
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http://dx.doi.org/10.1016/j.molp.2020.11.011DOI Listing
February 2021

Light participates in the auxin-dependent regulation of plant growth.

J Integr Plant Biol 2021 May 16;63(5):819-822. Epub 2021 Feb 16.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China.

Light is the energy source for plant photosynthesis and influences plant growth and development. Through multiple photoreceptors, plant interprets light signals through various downstream phytohormones such as auxin. Recently, Chen et al. (2020) uncover a new layer of regulation in IPyA pathway of auxin biosynthesis by light. Here we highlight recent studies about how light controls plant growth through regulating auxin biosynthesis and signaling.
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http://dx.doi.org/10.1111/jipb.13036DOI Listing
May 2021

CO is a key constituent of the plant growth-promoting volatiles generated by bacteria in a sealed system.

Plant Cell Rep 2021 Jan 3;40(1):59-68. Epub 2020 Oct 3.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, Shandong, China.

Key Message: Plant growth is greatly inhibited in tightly sealed Petri dishes for lack of CO. Bacteria which co-cultured with plant can produce CO to promote plant growth in sealed systems. Bacteria produce a wide variety of volatiles, some of which can support and others can damage plant growth. It is a controversial issue whether CO or other bacterial volatile compounds promote plant growth in sealed systems. CO is critical for photosynthesis. Here, we show that CO is a key constituent of the plant growth-promoting volatiles generated by bacteria in a sealed system. We revealed that the growth of Arabidopsis seedlings in an airtight container was retarded due to insufficient supply of the CO. When either CO was introduced into the container, or the seedlings were co-cultured along with certain bacterial species, the plants' growth was restored.

Conclusion: The benefit of co-culturing was largely due to the CO generated by respiration of the bacteria.
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http://dx.doi.org/10.1007/s00299-020-02610-3DOI Listing
January 2021

Antagonistic Interaction between Auxin and SA Signaling Pathways Regulates Bacterial Infection through Lateral Root in Arabidopsis.

Cell Rep 2020 08;32(8):108060

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, Shandong, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, China. Electronic address:

Pathogen entry into host tissues is a critical and first step in infections. In plants, the lateral roots (LRs) are a potential entry and colonization site for pathogens. Here, using a GFP-labeled pathogenic bacterium Pseudomonas syringae pv. tomato strain DC3000 (Pto DC3000), we observe that virulent Pto DC3000 invades plants through emerged LRs in Arabidopsis. Pto DC3000 strongly induced LR formation, a process that was dependent on the AUXIN RESPONSE FACTOR7 (ARF7)/ARF19-LATERAL ORGAN BOUNDARIES-DOMAIN (LBD) regulatory module. We show that salicylic acid (SA) represses LR formation, and several mutants defective in SA signaling are also involved in Pto DC3000-induced LR development. Significantly, ARF7, a well-documented positive regulator of LR development, directly represses the transcription of PR1 and PR2 to promote LR development. This study indicates that ARF7-mediated auxin signaling antagonizes with SA signaling to control bacterial infection through the regulation of LR development.
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http://dx.doi.org/10.1016/j.celrep.2020.108060DOI Listing
August 2020

The pre-mRNA splicing factor RDM16 regulates root stem cell maintenance in Arabidopsis.

J Integr Plant Biol 2021 Apr 16;63(4):662-678. Epub 2020 Sep 16.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China.

Pre-mRNA (messenger RNA) splicing participates in the regulation of numerous biological processes in plants. For example, alternative splicing shapes transcriptomic responses to abiotic and biotic stress, and controls developmental programs. However, no study has revealed a role for splicing in maintaining the root stem cell niche. Here, a screen for defects in root growth in Arabidopsis thaliana identified an ethyl methane sulfonate mutant defective in pre-mRNA splicing (rdm16-4). The rdm16-4 mutant displays a short-root phenotype resulting from fewer cells in the root apical meristem. The PLETHORA1 (PLT1) and PLT2 transcription factor genes are important for root development and were alternatively spliced in rdm16-4 mutants, resulting in a disordered root stem cell niche and retarded root growth. The root cap of rdm16-4 contained reduced levels of cytokinins, which promote differentiation in the developing root. This reduction was associated with the alternative splicing of genes encoding cytokinin signaling factors, such as ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN5 and ARABIDOPSIS RESPONSE REGULATORS (ARR1, ARR2, and ARR11). Furthermore, expression of the full-length coding sequence of ARR1 or exogenous cytokinin application partially rescued the short-root phenotype of rdm16-4. This reveals that the RDM16-mediated alternative splicing of cytokinin signaling components contributes to root growth.
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http://dx.doi.org/10.1111/jipb.13006DOI Listing
April 2021

How Plant Hormones Mediate Salt Stress Responses.

Trends Plant Sci 2020 11 13;25(11):1117-1130. Epub 2020 Jul 13.

Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China. Electronic address:

Salt stress is one of the major environmental stresses limiting plant growth and productivity. To adapt to salt stress, plants have developed various strategies to integrate exogenous salinity stress signals with endogenous developmental cues to optimize the balance of growth and stress responses. Accumulating evidence indicates that phytohormones, besides controlling plant growth and development under normal conditions, also mediate various environmental stresses, including salt stress, and thus regulate plant growth adaptation. In this review, we mainly discuss and summarize how plant hormones mediate salinity signals to regulate plant growth adaptation. We also highlight how, in response to salt stress, plants build a defense system by orchestrating the synthesis, signaling, and metabolism of various hormones via multiple crosstalks.
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http://dx.doi.org/10.1016/j.tplants.2020.06.008DOI Listing
November 2020

Differentially charged nanoplastics demonstrate distinct accumulation in Arabidopsis thaliana.

Nat Nanotechnol 2020 09 22;15(9):755-760. Epub 2020 Jun 22.

Stockbridge School of Agriculture, University of Massachusetts , Amherst, MA, USA.

Although the fates of microplastics (0.1-5 mm in size) and nanoplastics (<100 nm) in marine environments are being increasingly well studied, little is known about the behaviour of nanoplastics in terrestrial environments, especially agricultural soils. Previous studies have evaluated the consequences of nanoplastic accumulation in aquatic plants, but there is no direct evidence for the internalization of nanoplastics in terrestrial plants. Here, we show that both positively and negatively charged nanoplastics can accumulate in Arabidopsis thaliana. The aggregation promoted by the growth medium and root exudates limited the uptake of amino-modified polystyrene nanoplastics with positive surface charges. Thus, positively charged nanoplastics accumulated at relatively low levels in the root tips, but these nanoplastics induced a higher accumulation of reactive oxygen species and inhibited plant growth and seedling development more strongly than negatively charged sulfonic-acid-modified nanoplastics. By contrast, the negatively charged nanoplastics were observed frequently in the apoplast and xylem. Our findings provide direct evidence that nanoplastics can accumulate in plants, depending on their surface charge. Plant accumulation of nanoplastics can have both direct ecological effects and implications for agricultural sustainability and food safety.
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http://dx.doi.org/10.1038/s41565-020-0707-4DOI Listing
September 2020

PIFs coordinate shade avoidance by inhibiting auxin repressor ARF18 and metabolic regulator QQS.

New Phytol 2020 10 16;228(2):609-621. Epub 2020 Jul 16.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, Shandong, 266237, China.

Shade avoidance syndrome (SAS) arises in densely growing plants that compete for light. In Arabidopsis thaliana, phytochrome interacting factor (PIF) proteins link the perception of shade to stem elongation via auxin production. Here, we report that PIFs inhibit the shade-induced expression of AUXIN RESPONSE FACTOR 18 (ARF18), and ARF18 represses auxin signaling. Therefore, PIF-mediated inhibition of ARF18 enhances auxin-dependent hypocotyl elongation in simulated shade. Furthermore, we show that both PIFs and ARF18 directly repress qua-quine starch (QQS), which controls the allocation of carbon and nitrogen. Shade-repressed QQS attenuates the conversion of starch to protein and thus reduced leaf area. Our results suggest that PIF-dependent gene regulation coordinates multiple SAS responses, including altered stem growth via ARF18, as well as altered leaf growth and metabolism via QQS.
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http://dx.doi.org/10.1111/nph.16732DOI Listing
October 2020

AtHB7/12 Regulate Root Growth in Response to Aluminum Stress.

Int J Mol Sci 2020 Jun 7;21(11). Epub 2020 Jun 7.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, China.

Aluminum (Al) stress is a major limiting factor for plant growth and crop production in acid soils. At present, only a few transcription factors involved in the regulation of Al resistance have been characterized. Here, we used reversed genetic approach through phenotype analysis of overexpressors and mutants to demonstrate that AtHB7 and AtHB12, two HD-Zip I transcription factors, participate in Al resistance. In response to Al stress, and displayed different dynamic expression patterns. Although both AtHB7 and AtHB12 positively regulate root growth in the absence of Al stress, our results showed that AtHB7 antagonizes with AtHB12 to control root growth in response to Al stress. The double mutant displayed a wild-type phenotype under Al stress. Consistently, our physiological analysis showed that AtHB7 and AtHB12 oppositely regulate the capacity of cell wall to bind Al. Yeast two hybrid assays showed that AtHB7 and AtHB12 could form homo-dimers and hetero-dimers in vitro, suggesting the interaction between AtHB7 and AtHB12 in the regulation of root growth. The conclusion was that AtHB7 and AtHB12 oppositely regulate Al resistance by affecting Al accumulation in root cell wall.
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http://dx.doi.org/10.3390/ijms21114080DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312248PMC
June 2020

KUP9 maintains root meristem activity by regulating K and auxin homeostasis in response to low K.

EMBO Rep 2020 06 6;21(6):e50164. Epub 2020 Apr 6.

State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing, China.

Potassium (K) is essential for plant growth and development. Here, we show that the KUP/HAK/KT K transporter KUP9 controls primary root growth in Arabidopsis thaliana. Under low-K conditions, kup9 mutants displayed a short-root phenotype that resulted from reduced numbers of root cells. KUP9 was highly expressed in roots and specifically expressed in quiescent center (QC) cells in root tips. The QC acts to maintain root meristem activity, and low-K conditions induced QC cell division in kup9 mutants, resulting in impaired root meristem activity. The short-root phenotype and enhanced QC cell division in kup9 mutants could be rescued by exogenous auxin treatment or by specifically increasing auxin levels in QC cells, suggesting that KUP9 affects auxin homeostasis in QC cells. Further studies showed that KUP9 mainly localized to the endoplasmic reticulum (ER), where it mediated K and auxin efflux from the ER lumen to the cytoplasm in QC cells under low-K conditions. These results demonstrate that KUP9 maintains Arabidopsis root meristem activity and root growth by regulating K and auxin homeostasis in response to low-K stress.
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http://dx.doi.org/10.15252/embr.202050164DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7271654PMC
June 2020

The lagged effect of air pollution on human eosinophils: a distributed lag non-linear model.

Int J Occup Med Environ Health 2020 Apr 1;33(3):299-310. Epub 2020 Apr 1.

Shanghai Jiao Tong University School of Medicine, Shanghai, China (Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital).

Objectives: The aim of this study was to determine the lag between exposure to air pollutants and changes in human eosinophil counts.

Material And Methods: This was a retrospective study employing 246 425 physical examination records dated December 2013 - December 2016 from Chengdu, China. The authors determined the prevalence of individuals with eosinophil counts above the normal reference range each day. A distributed lag non-linear model was used to evaluate the lagged effect of each air pollutant on eosinophil counts. The lagged effects of each air pollutant were counted and presented with smoothing splines.

Results: The effects of air pollutants such as particulate matter (PM2.5, aerodynamic diameters <2.5 μm; PM10, aerodynamic diameters <10 μm), nitrogen dioxide (NO2) and ozone (O3) were evaluated. In women, the effects of PM2.5 (RR = 1.154, 95% CI: 1.061-1.255) and PM10 (RR = 1.309, 95% CI: 1.130-1.517) reached the maximum values on lag day 0. In men, there was no significant effect of PM2.5, but significant effects of PM10 were found for lag days 20-28. The effects of NO2 and O3 on eosinophils were not statistically significant for either gender.

Conclusions: The air pollutants of PM10 have a significant effect on human eosinophils for both women and men, but with different temporal patterns, with women showing a lag of 0-5 days and men showing a lag of 20-28 days. In addition, PM2.5 was significant for women with a lag of 0-3 days but it was not significant for men. Int J Occup Med Environ Health. 2020;33(3):299-310.
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http://dx.doi.org/10.13075/ijomeh.1896.01528DOI Listing
April 2020

IPyA glucosylation mediates light and temperature signaling to regulate auxin-dependent hypocotyl elongation in .

Proc Natl Acad Sci U S A 2020 03 9;117(12):6910-6917. Epub 2020 Mar 9.

The Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, People's Republic of China;

Auxin is a class of plant hormone that plays a crucial role in the life cycle of plants, particularly in the growth response of plants to ever-changing environments. Since the auxin responses are concentration-dependent and higher auxin concentrations might often be inhibitory, the optimal endogenous auxin level must be closely controlled. However, the underlying mechanism governing auxin homeostasis remains largely unknown. In this study, a UDP-glycosyltransferase (UGT76F1) was identified from , which participates in the regulation of auxin homeostasis by glucosylation of indole-3-pyruvic acid (IPyA), a major precursor of the auxin indole-3-acetic acid (IAA) biosynthesis, in the formation of IPyA glucose conjugates (IPyA-Glc). In addition, UGT76F1 was found to mediate hypocotyl growth by modulating active auxin levels in a light- and temperature-dependent manner. Moreover, the transcription of was demonstrated to be directly and negatively regulated by PIF4, which is a key integrator of both light and temperature signaling pathways. This study sheds a light on the trade-off between IAA biosynthesis and IPyA-Glc formation in controlling auxin levels and reveals a regulatory mechanism for plant growth adaptation to environmental changes through glucosylation of IPyA.
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http://dx.doi.org/10.1073/pnas.2000172117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7104303PMC
March 2020

PRH1 mediates ARF7-LBD dependent auxin signaling to regulate lateral root development in Arabidopsis thaliana.

PLoS Genet 2020 02 7;16(2):e1008044. Epub 2020 Feb 7.

The Key Laboratory of the Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China.

The development of lateral roots in Arabidopsis thaliana is strongly dependent on signaling directed by the AUXIN RESPONSE FACTOR7 (ARF7), which in turn activates LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factors (LBD16, LBD18 and LBD29). Here, the product of PRH1, a PR-1 homolog annotated previously as encoding a pathogen-responsive protein, was identified as a target of ARF7-mediated auxin signaling and also as participating in the development of lateral roots. PRH1 was shown to be strongly induced by auxin treatment, and plants lacking a functional copy of PRH1 formed fewer lateral roots. The transcription of PRH1 was controlled by the binding of both ARF7 and LBDs to its promoter region.
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http://dx.doi.org/10.1371/journal.pgen.1008044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7006904PMC
February 2020

Nanoplastics Promote Microcystin Synthesis and Release from Cyanobacterial .

Environ Sci Technol 2020 03 30;54(6):3386-3394. Epub 2020 Jan 30.

Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, P. R. China.

Although the fate of nanoplastics (<100 nm) in freshwater systems is increasingly well studied, much less is known about its potential threats to cyanobacterial blooms, the ultimate phenomenon of eutrophication occurrence worldwide. Previous studies have evaluated the consequences of nanoplastics increasing the membrane permeability of microbes, however, there is no direct evidence for interactions between nanoplastics and microcystin; intracellular hepatotoxins are produced by some genera of cyanobacteria. Here, we show that the amino-modified polystyrene nanoplastics (PS-NH) promote microcystin synthesis and release from , a dominant species causing cyanobacterial blooms, even without the change of coloration. We demonstrate that PS-NH inhibits photosystem II efficiency, reduces organic substance synthesis, and induces oxidative stress, enhancing the synthesis of microcystin. Furthermore, PS-NH promotes the extracellular release of microcystin from via transporter protein upregulation and impaired cell membrane integrity. Our findings propose that the presence of nanoplastics in freshwater ecosystems might enhance the threat of eutrophication to aquatic ecology and human health.
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http://dx.doi.org/10.1021/acs.est.9b06085DOI Listing
March 2020

Non-canonical AUX/IAA protein IAA33 competes with canonical AUX/IAA repressor IAA5 to negatively regulate auxin signaling.

EMBO J 2020 01 16;39(1):e101515. Epub 2019 Oct 16.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China.

The phytohormone auxin controls plant growth and development via TIR1-dependent protein degradation of canonical AUX/IAA proteins, which normally repress the activity of auxin response transcription factors (ARFs). IAA33 is a non-canonical AUX/IAA protein lacking a TIR1-binding domain, and its role in auxin signaling and plant development is not well understood. Here, we show that IAA33 maintains root distal stem cell identity and negatively regulates auxin signaling by interacting with ARF10 and ARF16. IAA33 competes with the canonical AUX/IAA repressor IAA5 for binding to ARF10/16 to protect them from IAA5-mediated inhibition. In contrast to auxin-dependent degradation of canonical AUX/IAA proteins, auxin stabilizes IAA33 protein via MITOGEN-ACTIVATED PROTEIN KINASE 14 (MPK14) and does not affect IAA33 gene expression. Taken together, this study provides insight into the molecular functions of non-canonical AUX/IAA proteins in auxin signaling transduction.
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http://dx.doi.org/10.15252/embj.2019101515DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6939196PMC
January 2020

Asymmetric distribution of cytokinins determines root hydrotropism in Arabidopsis thaliana.

Cell Res 2019 Dec 10;29(12):984-993. Epub 2019 Oct 10.

Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, 730000, Lanzhou, China.

The phenomenon of plant root tips sensing moisture gradient in soil and growing towards higher water potential is designated as root hydrotropism, which is critical for plants to survive when water is a limited factor. Molecular mechanisms regulating such a fundamental process, however, are largely unknown. Here we report our identification that cytokinins are key signaling molecules directing root growth orientation in a hydrostimulation (moisture gradient) condition. Lower water potential side of the root tip shows more cytokinin response relative to the higher water potential side. Consequently, two cytokinin downstream type-A response regulators, ARR16 and ARR17, were found to be up-regulated at the lower water potential side, causing increased cell division in the meristem zone, which allows the root to bend towards higher water potential side. Genetic analyses indicated that various cytokinin biosynthesis and signaling mutants, including the arr16 arr17 double mutant, are significantly less responsive to hydrostimulation. Consistently, treatments with chemical inhibitors interfering with either cytokinin biosynthesis or cell division completely abolished root hydrotropic response. Asymmetrically induced expression of ARR16 or ARR17 effectively led to root bending in both wild-type and miz1, a previously known hydrotropism-defective mutant. These data demonstrate that asymmetric cytokinin distribution is a primary determinant governing root hydrotropism.
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http://dx.doi.org/10.1038/s41422-019-0239-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6951336PMC
December 2019

Relationship of gender and age on thyroid hormone parameters in a large Chinese population.

Arch Endocrinol Metab 2020 Feb 30;64(1):52-58. Epub 2019 Sep 30.

Translational Medicine Research Hospital, Chinese Academy of Sciences Sichuan, Chengdu, China.

Objective This study aimed to present the impact of age and gender on thyroid hormone levels in a large Chinese population with sufficient iodine intake. Subjects and methods A total of 83643 individuals were included and were stratified by age and gender. The median, 2.5th and 97.5th of thyrotropin (TSH), free triiodothyronine (FT3), free thyroxine (FT4) and FT3/FT4 ratio were calculated for both genders for every decade from 18 to over 80 years. TSH, FT3, FT4, FT3/FT4 distribution in each age group was evaluated for females and males using smoothing splines in the generalized additive models (GAM). TSH concentrations were compared in the different age groups in gender. Results In the over 80s age group, the TSH level (median: 2.57 mIU/L, 2.5th-97.5th: 0.86-7.56 mIU/L) was significantly higher than other age groups, irrespective to gender (P<0.001). Females had a higher TSH value than males in all age groups (P<0.001). Results of the smoothing curves showed that TSH increased with age, FT3 concentration was higher in males than in females and the tendency of the FT3/FT4 ratio was basically similar to that of FT3. TSH concentration in the 50s age group (median 2.48 mIU/L for females versus 2.00 mIU/L for males) was significantly higher than that in the 30s age group (median 2.18 mIU/L for females versus median 1.85 mIU/L for males). Conclusions In accord with increasing TSH values during aging, females and older adults have lower FT3 values and lower FT3/FT4 ratios, while the FT4 values remain stable.
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http://dx.doi.org/10.20945/2359-3997000000179DOI Listing
February 2020

Regulates Auxin Response and Compound Leaf Morphogenesis in .

Front Plant Sci 2019 16;10:1024. Epub 2019 Aug 16.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, China.

WUSCHEL (WUS) is thought to be required for the establishment of the shoot stem cell niche in . (), a gene that encodes a WUS-related homeobox family transcription factor, is thought to be the ortholog of the gene. plays conserved roles in shoot apical meristem (SAM) and axillary meristem (AM) maintenance. is also involved in compound leaf morphogenesis in ; however, its regulatory mechanism has not yet been explored. Here, the significance of in leaf development was investigated. Unlike in , was transcribed not only in the SAM and AM but also in the leaf. Both the patterning of the compound leaves and the shape of the leaf margin in mutant were abnormal. The transcriptional profile of the gene , which encodes an auxin efflux carrier, was impaired and the plants' auxin response was compromised. Further investigations revealed that positively regulated auxin response likely through the recruitment of MtTPL/MtTPRs into the HDL repressor complex. Its participation in auxin-dependent compound leaf morphogenesis is of interest in the context of the functional conservation and neo-functionalization of the products of orthologs.
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http://dx.doi.org/10.3389/fpls.2019.01024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6707262PMC
August 2019

GUN1-Interacting Proteins Open the Door for Retrograde Signaling.

Trends Plant Sci 2019 10 22;24(10):884-887. Epub 2019 Jul 22.

Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan 250014, Shandong, China. Electronic address:

Genomes Uncoupled 1 (GUN1) plays a critical role in various retrograde signaling pathways. Despite numerous studies, the precise molecular mechanism underlying GUN1-mediated retrograde signaling remains elusive. Recently, MORF2 and cpHSC70 have been identified as GUN1-interacting proteins, linking retrograde signaling with plastid RNA editing and cytosolic folding stress, respectively.
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http://dx.doi.org/10.1016/j.tplants.2019.07.005DOI Listing
October 2019

Reconsidering the HbA1c Cutoff for Diabetes Diagnosis Based on a Large Chinese Cohort.

Exp Clin Endocrinol Diabetes 2021 Feb 30;129(2):86-92. Epub 2019 Apr 30.

Department of Endocrine and Metabolic Diseases, Ruijin Hospital North, Shanghai JiaoTong University School of Medicine, Shanghai, China.

Introduction: The HbA1c has been considered as the 'gold standard' in diabetes diagnosis and management, however, age, gender and body mass index (BMI) might have certain effects on HbA1c. We are aiming to further investigate the correlation between age and HbA1c, and whether it was affected by gender and BMI.

Methods: A cross-sectional survey including 135,893 nondiabetic individuals who took the physical examination between 2013 and 2017 was conducted. The subjects were grouped by gender, age and BMI, and the interactive and independent effects of the 3 factors on the HbA1c were detected. The median and 95% confidence interval (CI) of HbA1c levels were calculated.

Results: The HbA1c levels gradually increased along with age, both in female and male, and there is a positive association between BMI and the HbA1c. The difference on HbA1c in gender was associated with both age and BMI, the age-related increase in HbAlc was accentuated in the subgroup with higher BMI, and there was a marked accentuation of the positive association between BMI and HbA1c as age increased. In almost all the young and middle-aged (aged 20-59) subgroups, the 97.5 percentiles of HbA1c levels were lower than 6.5%, suggesting that the single HbA1c cutoff value is probably not applicable to the young and middle-aged population.

Conclusions: We recommend that the effects of age, gender and BMI should be taken into consideration when using HbA1c for the diagnosis and management of diabetes, especially in the young and middle-aged population.
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http://dx.doi.org/10.1055/a-0833-8119DOI Listing
February 2021

Complete Paternal Uniparental Disomy of Chromosome 2 in an Asian Female Identified by Short Tandem Repeats and Whole Genome Sequencing.

Cytogenet Genome Res 2019 17;157(4):197-202. Epub 2019 Apr 17.

Uniparental disomy (UPD) is a rare type of chromosomal aberration that has sometimes been detected in paternity testing. We examined a 3-person family (father, mother, daughter) first by using short tandem repeat markers, which revealed 4 markers, TPOX, D2S1338, D2S1772, and D2S441, on chromosome 2 that were not transmitted in a Mendelian style. We then performed whole genome sequencing (WGS) to determine the range of the UPD. Chromosome 2 in the daughter showed a complete paternal UPD. To the best of our knowledge, this is the 4th case of complete paternal UPD of chromosome 2 with no clinical phenotype. Our study suggests that WGS, when performed to enhance the accuracy and reliability of parentage testing, can provide a powerful method to detect an UPD.
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http://dx.doi.org/10.1159/000499893DOI Listing
July 2019

Contribution of Microbial Inter-kingdom Balance to Plant Health.

Mol Plant 2019 02 26;12(2):148-149. Epub 2019 Jan 26.

State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Science, Beijing 100101, China; CAS-JIC Centre of Excellence for Plant and Microbial Science, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, College of Advanced Agricultural Sciences, Beijing 100039, China. Electronic address:

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http://dx.doi.org/10.1016/j.molp.2019.01.016DOI Listing
February 2019

Local Auxin Biosynthesis Mediates Plant Growth and Development.

Trends Plant Sci 2019 01 15;24(1):6-9. Epub 2018 Nov 15.

The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, Shandong, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, Shandong, China. Electronic address:

Auxin is one of the most important plant hormones controlling various aspects of plant growth and development. Here, we highlight three recent papers that shed light on how local auxin biosynthesis contributes to plant growth and development in response to endogenous developmental signals and exogenous environmental cues, such as shade and aluminum stress.
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http://dx.doi.org/10.1016/j.tplants.2018.10.014DOI Listing
January 2019

ROS: The Fine-Tuner of Plant Stem Cell Fate.

Trends Plant Sci 2018 10 18;23(10):850-853. Epub 2018 Aug 18.

State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, China; The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, Shandong, China. Electronic address:

Reactive oxygen species (ROS) are initially considered to be toxic by-products of aerobic metabolism. However, accumulating evidence has shown that ROS also act as key regulators for the progression of several basic biological processes. Recent studies highlight the key role of ROS in root and shoot stem cell niche maintenance.
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http://dx.doi.org/10.1016/j.tplants.2018.07.010DOI Listing
October 2018

Survivin is critically involved in VEGFR2 signaling-mediated esophageal cancer cell survival.

Biomed Pharmacother 2018 Nov 4;107:139-145. Epub 2018 Aug 4.

Department of Oncology, People's Hospital of Rizhao, Rizhao, Shandong, 276826, China.

Vascular endothelial growth factor (VEGF) signaling promotes angiogenesis by stimulating the migration and proliferation of endothelial cells. The aim of this study was to investigate the expression of Survivin and VEGF receptor 1/2/3 (VEGFR 1/2/3) in esophageal carcinoma tissues (ECTs), and to explore the therapy effect of the suppression of VEGFR2 signaling. Here, we found that VEGFR2 and Survivin had high expressions and a significant correlation (r = 0.874, P < 0.002) in ECTs. Further, we found that VEGFR2 signaling could activate the AKT1/MDM2/Survivin pathway. The inhibition of VEGFR2 signaling with the XL184 treatment downregulated the phosphorylation of AKT1 and MDM2, and then, increased the activation of Caspase 3/7, resulting in the reduction of cell viability and the apoptosis of HUVECs. Additionally, in the esophageal tumor model, the tumor growth was significantly suppressed by blocking Survivin and the suppression of tumor growth was more effective in the combined treatment by blocking Survivin and Bcl-xl/Bcl-2. Our data thus revealed that Survivin in the signal downstream of VEGFR2 played an important role in esophageal cancer cell survival and might be a potential candidate target for the combined therapy for esophageal cancer.
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http://dx.doi.org/10.1016/j.biopha.2018.05.134DOI Listing
November 2018

Ethylene promotes cadmium-induced root growth inhibition through EIN3 controlled XTH33 and LSU1 expression in Arabidopsis.

Plant Cell Environ 2018 10 12;41(10):2449-2462. Epub 2018 Jul 12.

Shandong University, The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Science, Jinan, China.

Cadmium (Cd) stress is one of the most serious heavy metal stresses limiting plant growth and development. However, the molecular mechanisms underlying Cd-induced root growth inhibition remain unclear. Here, we found that ethylene signalling positively regulates Cd-induced root growth inhibition. Arabidopsis seedlings pretreated with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid exhibited enhanced Cd-induced root growth inhibition, whereas the addition of the ethylene biosynthesis inhibitor aminoethoxyvinyl glycine decreased Cd-induced root growth inhibition. Consistently, ethylene-insensitive mutants, such as ein4-1, ein3-1 eil1-1 double mutant, and EBF1ox, displayed an increased tolerance to Cd. Furthermore, we also observed that Cd inhibited EIN3 protein degradation, a process that was regulated by ethylene signalling. Genetic and biochemical analyses showed that EIN3 enhanced root growth inhibition under Cd stress through direct binding to the promoters and regulating the expression of XTH33 and LSU1, which encode key regulators of cell wall extension and sulfur metabolic process, respectively. Collectively, our study demonstrates that ethylene plays a positive role in Cd-regulated root growth inhibition through EIN3-mediated transcriptional regulation of XTH33 and LSU1 and provides a molecular framework for the integration of environmental signals and intrinsic regulators in modulating plant root growth.
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http://dx.doi.org/10.1111/pce.13361DOI Listing
October 2018

Auxin Efflux Carrier ZmPGP1 Mediates Root Growth Inhibition under Aluminum Stress.

Plant Physiol 2018 06 2;177(2):819-832. Epub 2018 May 2.

The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, College of Life Sciences, Shandong University, Jinan 250100, Shandong, China

Auxin has been shown to enhance root growth inhibition under aluminum (Al) stress in Arabidopsis (). However, in maize (), auxin may play a negative role in the Al-induced inhibition of root growth. In this study, we identified mutants deficient in the maize auxin efflux carrier P-glycoprotein (ZmPGP1) after ethyl methanesulfonate mutagenesis and used them to elucidate the contribution of ZmPGP1 to Al-induced root growth inhibition. Root growth in the mutant, which forms shortened roots and is hyposensitive to auxin, was less inhibited by Al stress than that in the inbred line B73. In the mutants, the root tips displayed higher auxin accumulation and enhanced auxin signaling under Al stress, which was also consistent with the increased expression of auxin-responsive genes. Based on the behavior of the auxin-responsive marker transgene, , we concluded that Al stress reduced the level of auxin in the root tip, which contrasts with the tendency of Al stress-induced Arabidopsis plants to accumulate more auxin in their root tips. In addition, Al stress induced the expression of Therefore, in maize, Al stress is associated with reduced auxin accumulation in root tips, a process that is regulated by ZmPGP1 and thus causes inhibition of root growth. This study provides further evidence about the role of auxin and auxin polar transport in Al-induced root growth regulation in maize.
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http://dx.doi.org/10.1104/pp.17.01379DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6001327PMC
June 2018