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Aluminum-activated Oxalate Secretion does not Associate with Internal Content among Some Oxalate Accumulators

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Journal of Integrative Plant Biology 2008年第9期50卷 1103-1107页

作者： jian Li Yang LeiZhang shao jian zheng State Key Laboratory of Plant Biochemistry and Physiology College of Life Sciences Zhejiang University Hangzhou 310058 China Department of Biology College of Food Science and Biotechnology Engineering Zhejiang Gongshang University Hangzhou 310035 China College of Environmental and Resource Sciences Zhejiang University Hangzhou 310029 China

Although aluminum （AI）-activated secretion of oxalate has been considered to be an important AI-exclusion mechanism, whether it is a general response in oxalate accumulators and related to oxalate content in roots are still not clear. Here, we examined the oxalate secretion and oxalate content in some oxalate accumulators, and investigated the role of oxalate secretion in AI resistance. When oxalate content in amaranth roots was decreased by about 50% with the increased ratio of NH4^＋-N to NO3^- -N in nutrient solution, the amount of AI-activated oxalate secretion still remained constant. There was no relationship between the content of the water soluble oxalate in four species of oxalate accumulators and the amount of the AI-activated oxalate secretion in roots. Furthermore, oxalate secretion is poorly associated with AI resistance among these species. Based on the above results, we concluded that although all of the oxalate accumulators tested could secrete oxalate rapidly, the density of anion channels in plasma membrane may play a more important role in AI-activated oxalate secretion.

关键词： aluminum toxicity Amaranthus anion channel oxalate accumulator oxalate secretion

Protecting Cell Walls from Binding Aluminum by Organic Acids Contributes to Aluminum Resistance

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Journal of Integrative Plant Biology 2009年第6期51卷 574-580页

作者： Ya-Ying Li Yue-Jiao Zhang Yuan Zhou jian-Li Yang shao-jian zheng Ministry of Agriculture Key Laboratory for Non-Point Pollution Control Zhejiang University Hangzhou 310029 China State Key Laboratory of Plant Physiology and Biochemistry College of Life Sciences Zhejiang University Hangzhou 310058 China

Aluminum-induced secretion of organic acids from the root apex has been demonstrated to be one major AI resistance mechanism in plants. However, whether the organic acid concentration is high enough to detoxify AI in the growth medium is frequently questioned. The genotypes of AI-resistant wheat, Cassia tora L. and buckwheat secrete malate, citrate and oxalate, respectively. In the present study we found that at a 35% inhibition of root elongation, the AI activities in the solution were 10, 20, and 50 μM with the corresponding malate, citrate, and oxalate exudation at the rates of 15, 20 and 21 nmol/cm2 per 12 h, respectively, for the above three plant species. When exogenous organic acids were added to ameliorate AI toxicity, twofold and eightfold higher oxalate and malate concentrations were required to produce the equal effect by citrate. After the root apical cell walls were isolated and preincubated in 1 mM malate, oxalate or citrate solution overnight, the total amount of AI adsorbed to the cell walls all decreased significantly to a similar level, implying that these organic acids own an equal ability to protect the cell walls from binding AI. These findings suggest that protection of cell walls from binding AI by organic acids may contribute significantly to AI resistance.

关键词： adsorption and desorption aluminum toxicity cell wall chelation detoxification organic acid.

Iron Deficiency-induced Increase of Root Branching Contributes to the Enhanced Root Ferric Chelate Reductase Activity

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Journal of Integrative Plant Biology 2008年第12期50卷 1557-1562页

作者： Chong-Wei Jin Wei-Wei Chen Zhi-Bin Meng shao-jian zheng Ministry of Education Key Laboratory of Environment Remediation and Ecosystem Health College of Environmental and Resource Science Zhejiang University Hangzhou 310029 China State Key Laboratory of Plant Biochemistry and Physiology College of Life Sciences Zhejiang University Hangzhou 310058 China

In various plant species, Fe deficiency increases lateral root branching. However, whether this morphological alteration contributes to the Fe deficiency-induced physiological responses still remains to be demonstrated. In the present research, we demonstrated that the lateral root development of red clover （Trifolium pretense L.） was significantly enhanced by Fe deficient treatment, and the total lateral root number correlated well with the Fe deficiency-induced ferric chelate reductase （FCR） activity. By analyzing the results from Dasgan et al. （2002）, we also found that although the two tomato genotypes line227/1 （P1） and Roza （P2） and their reciprocal F1 hybrid lines （＂P1 × P2＂ and ＂P2 ×PI＂） were cultured under two different lower Fe conditions （10^-6 and 10^-7 M FeEDDHA）, their FCR activities are significantly correlated with the lateral root number. More interestingly, the -Fe chlorosis tolerant ability of these four tomato lines displays similar trends with the lateral root density. Taking these results together, it was proposed that the Fe deficiency-induced increases of the lateral root should play an important role in resistance to Fe deficiency, which may act as harnesses of a useful trait for the selection and breeding of more Fe-efficient crops among the genotypes that have evolved a Fe deficiency-induced Fe uptake system.

关键词： Fe deficiency ferric chelate reductase lateral root red clover tomato.

Abscisic acid-dependent PMT1 expression regulates salt tolerance by alleviating abscisic acid-mediated reactive oxygen species production in Arabidopsis

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Journal of Integrative Plant Biology 2022年第9期64卷 1803-1820页

作者： Qi Yu He jian Feng Jin He Qiang Lou Feng Feng Dang Ji Ming Xu shao jian zheng jian Li Yang State Key Laboratory of Plant Physiology and Biochemistry College of Life SciencesZhejiang UniversityHangzhou310058 China State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityHangzhou311300 China State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources South China Agricultural UniversityGuangzhou510642 China

Phosphocholine(PCho)is an intermediate metabolite of nonplastid plant membranes that is essential for salt ***,how PCho metabolism modulates response to salt stress remains ***,we characterize the role of phosphoethanolamine N-methyltransferase 1(PMT1)in salt stress tolerance in Arabidopsis thaliana using a T-DNA insertional mutant,geneediting alleles,and complemented *** pmt1 mutants showed a severe inhibition of root elongation when exposed to salt stress,but exogenous ChoCl or lecithin rescued this ***1 also displayed altered glycerolipid metabolism under salt stress,suggesting that glycerolipids contribute to salt ***,pmt1 mutants exhibited altered reactive oxygen species(ROS)accumulation and distribution,reduced cell division activity,and disturbed auxin distribution in the primary root compared with wild-type *** show that PMT1 expression is induced by salt stress and relies on the abscisic acid(ABA)signaling pathway,as this induction was abolished in the aba2-1 and pyl112458 ***,ABA aggravated the salt sensitivity of the pmt1 mutants by perturbing ROS distribution in the root *** together,we propose that PMT1 is an important phosphoethanolamine N-methyltransferase participating in root development of primary root elongation under salt stress conditions by balancing ROS production and distribution through ABA signaling.

关键词： abscisic acid(ABA) oxidative stress plasma membrane phosphoethanolamine N-methyltransferase phospholipid metabolism salt stress

Weak absorption test and defect analysis of optical coatings

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光学精密工程 2005年第4期13卷 430-434页

作者： HE Hong-bo LI Xia FAN Shu-hai ZHAO Yuan-an shao jian-da FAN zheng-xiu Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China

Surface thermal lensing technique was developed into a high-sensitive apparatus for weak absorption test and defect analysis of optical coatings. A continuous-wave 1 064 nm Nd:YAG laser and a He-Ne laser were employed as pump source and probe source, respectively. Low noise photoelectrical components and a lock-in amplifier were used for photo-thermal deformation signal detection. In order to improve sensitivity, the apparatus configuration was optimized by choosing appropriate parameters, including pump beam spot size, chopper frequency, detection distance, waist radius and position of probe beam. Coating samples were mounted on a x-y stage. Different procedures, such as single spot, linear scan and 2-dimension area scan, could be performed manually or automatically. Various optical coatings were prepared by both electron beam evaporation and ion beam sputtering deposition. High sensitivity was obtained and low to 1×10 -7 weak absorption was tested in low-loss coating samples. For the sensitivity extreme of the system, 1×10 -8 absorption was reason out to be measured by surface thermal lensing technique. Very small standard deviation was achieved for the reproducibility evaluation. Moreover, a spatial resolution of 25 micron was proved according to the area scan which traced out the profile of photo-thermal defects inside optical coatings. The system was employed in the analyses of optical absorption, absorption uniformity and defect characterization, and revealed the relationship between laser-induced damage and absorption of optical coatings.

关键词：光学涂覆技术吸收能力稳定性激光技术

Glucose alleviates cadmium toxicity by increasing cadmium fi xation in root cell wall and sequestration into vacuole in Arabidopsis

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Journal of Integrative Plant Biology 2015年第10期57卷 830-837页

作者： Yuan-Zhi Shi Xiao-Fang Zhu jiang-Xue Wan Gui-Xin Li shao-jian zheng Tea Research Institute of the Chinese Academy of Agricultural Sciences and the Key Laboratory for Plant Biology and Resource Application of Tea the Ministry of Agriculture State Key Laboratory of Plant Physiology and Biochemistry College of Life SciencesZhejiang University State Key Laboratory of Soil and Sustainable Agriculture China Institute of Soil Science the Chinese Academy of Science College of Agronomy and Biotechnology Zhejiang University

Glucose (Glu) is involved in not only plant physiological and developmental events but also plant responses to abiotic stresses. Here, we found that the exogenous Glu improved root and shoot growth, reduced shoot cadmium (Cd) concentration, and rescued Cd-induced chlorosis in Arabidopsis thaliana (Columbia ecotype, Col-0) under Cd stressed conditions. Glucose increased Cd retained in the roots, thus reducing its translocation from root to shoot significantly. The most Cd retained in the roots was found in the hemicellulose 1. Glucose combined with Cd (Glu t Cd) treatment did not affect the content of pectin and its binding capacity of Cd while it increased the content of hemicelluloses 1 and the amount of Cd retained in it significantly. Furthermore, Leadmium Green staining indicated that more Cd was compartmented into vacuoles in Glu t Cd treatment compared with Cd treatment alone, which was in accordance with the significant upregulation of the expression of tonoplast-localized metal transporter genes, suggesting that com-partmentation of Cd into vacuoles also contributes to the Glu-alleviated Cd toxicity. Taken together, we demonstrated that Glu-alleviated Cd toxicity is mediated through increas-ing Cd fixation in the root cell wall and sequestration into the vacuoles.

关键词： Arabidopsis cadmium tolerance glucose plant cell wall plant vacuole

Jasmonic acid alleviates cadmium toxicity in Arabidopsis via suppression of cadmium uptake and translocation

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Journal of Integrative Plant Biology 2020年第2期62卷 218-227页

作者： Gui Jie Lei Li Sun Ying Sun Xiao Fang Zhu Gui Xin Li shao jian zheng State Key Laboratory of Plant Physiology and Biochemistry College of Life SciencesZhejiang UniversityHangzhou 310058China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China College of Agronomy and Biotechnology Zhejiang UniversityHangzhou 310058China

Jasmonic acid(JA)is thought to be involved in plant responses to cadmium(Cd)stress,but the underlying molecular mechanisms are poorly ***,we show that Cd treatment rapidly induces the expression of genes promoting endogenous JA synthesis,and subsequently increases the JA concentration in Arabidopsis ***,exogenous methyl jasmonate(MeJA)alleviates Cd-generated chlorosis of new leaves by decreasing the Cd concentration in root cell sap and shoot,and decreasing the expression of the AtIRT1,AtHMA2 and AtHMA4 genes promoting Cd uptake and long-distance translocation,*** contrast,mutation of a key JA synthesis gene,At AOS,greatly enhances the expression of AtIRT1,AtHMA2 and AtHMA4,increases Cd concentration in both roots and shoots,and confers increased sensitivity to *** Me JA recovers the enhanced Cd-sensitivity of the ataos mutant,but not of atcoi1,a JA receptor *** addition,exogenous Me JA reduces NO levels in Cd-stressed Arabidopsis root *** together,our results suggest that Cd-induced JA acts via the JA signaling pathway and its effects on NO levels to positively restrict Cd accumulation and alleviates Cd toxicity in Arabidopsis via suppression of the expression of genes promoting Cd uptake and long-distance translocation.

关键词： Jasmonic acid cadmium uptake translocation

Alleviation by abscisic acid of Al toxicity in rice bean is not associated with citrate efflux but depends on ABI5-mediated signal transduction pathways

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Journal of Integrative Plant Biology 2019年第2期61卷 140-154页

作者： Wei Fan Jia Meng Xu Pei Wu Zhi Xin Yang He Qiang Lou Wei Wei Chen jian Fen Jin shao jian zheng jian Li Yang College of Resources and Environment Yunan Agricultural University State Key Laboratory of Plant Physiology and Biochemistry College of Life Sciences Zhejiang University Institute of Life Sciences College of Life and Environmental Sciences Hangzhou Normal University

Under conditions of aluminum(Al) toxicity,which severely inhibits root growth in acidic soils, plants rapidly alter their gene expression to optimize physiological fitness for survival. Abscisic acid(ABA) has been suggested as a mediator between Al stress and gene expression, but the underlying mechanisms remain largely unknown. Here,we investigated ABA-mediated Al-stress responses, using integrated physiological and molecular biology *** demonstrate that Al stress caused ABA accumulation in the root apex of rice bean(Vigna umbellata [Thunb.] Ohwi &Ohashi), which positively regulated Al tolerance. However,this was not associated with known Al-tolerance mechanisms. Transcriptomic analysis revealed that nearly one-third of the responsive genes were shared between the Al-stress and ABA treatments. We further identified a transcription factor, ABI5, as being positively involved in Al tolerance. Arabidopsis abi5 mutants displayed increased sensitivity to Al, which was not related to the regulation of AtALMT1 and AtMATE expression. Functional categorization of ABI5-mediated genes revealed the importance of cell wall modification and osmoregulation in Al tolerance, a finding supported by osmotic stress treatment on Al tolerance. Our results suggest that ABA signal transduction pathways provide an additional layer of regulatory control over Al tolerance in plants.

关键词： Alleviation by abscisic acid of Al toxicity in rice bean is not associated with citrate efflux but depends on ABI5-mediated sign ABA Figure ABI

An eukaryotic translation initiation factor, AteIF_5A-2,affects cadmium accumulation and sensitivity in Arabidopsis

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Journal of Integrative Plant Biology 2015年第10期57卷 848-858页

作者： Xiao-Yan Xu Zhong-Jie Ding Lei Chen Jin-Ying Yan Gui-Xin Li shao-jian zheng State Key Laboratory of Plant Physiology and Biochemistry College of Life Sciences Zhejiang University College of Agronomy and Biotechnology Zhejiang University

Cadmium (Cd) is one of the most toxic elements and can be accumulated in plants easily; meanwhile, eIF5A is a highly conserved protein in all eukaryotic organisms. The present work tried to investigate whether eIF5A is involved in Cd accumulation and sensitivity in Arabidopsis (Arabidopsis thaliana L.) by comparing the wild-type Columbia-0 (Col-0) with a knockdown mutant of AteIF5A-2, fbr12-3 under Cd stress conditions. The results showed that the mutant fbr12-3 accumulated more Cd in roots and shoots and had significantly lower chlorophyll content, shorter root length, and smaller biomass, suggesting that downregulation of AteIF5A-2 makes the mutant more Cd sensitive. Real-time polymerase chain reaction revealed that the expressions of metal transporters involved in Cd uptake and translocation including IRT1, ZIP1, AtNramp3, and AtHMA4 were significantly increased but the expressions of PCS1 and PCS2 related to Cd detoxification were decreased notably in fbr12-3 compared with Col-0. As a result, an increase in MDA and H2O2 content but decrease in root trolox, glutathione and proline content under Cd stress was observed, indicating that a severer oxidative stress occurs in the mutant. All these results demonstrated for the first time that AteIF5A influences Cd sensitivity by affecting Cd uptake, accumulation, and detoxification in Arabidopsis.

关键词： Arabidopsis AteIF5A cadmium toxicity metal transporter oxidative stress