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Dong Q, Wu Y, Wang H, Li B, Huang R, Li H, Tao Q, Li Q, Tang X, Xu Q, Luo Y, Wang C. Integrated morphological, physiological and transcriptomic analyses reveal response mechanisms of rice under different cadmium exposure routes. J Hazard Mater 2024; 466:133688. [PMID: 38310845 DOI: 10.1016/j.jhazmat.2024.133688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/04/2024] [Accepted: 01/30/2024] [Indexed: 02/06/2024]
Abstract
Rice (Oryza sativa) is one of the major cereal crops and takes up cadmium (Cd) more readily than other crops. Understanding the mechanism of Cd uptake and defense in rice can help us avoid Cd in the food chain. However, studies comparing Cd uptake, toxicity, and detoxification mechanisms of leaf and root Cd exposure at the morphological, physiological, and transcriptional levels are still lacking. Therefore, experiments were conducted in this study and found that root Cd exposure resulted in more severe oxidative and photosynthetic damage, lower plant biomass, higher Cd accumulation, and transcriptional changes in rice than leaf Cd exposure. The activation of phenylpropanoids biosynthesis in both root and leaf tissues under different Cd exposure routes suggests that increased lignin is the response mechanism of rice under Cd stress. Moreover, the roots of rice are more sensitive to Cd stress and their adaptation responses are more pronounced than those of leaves. Quantitative PCR revealed that OsPOX, OsCAD, OsPAL and OsCCR play important roles in the response to Cd stress, which further emphasize the importance of lignin. Therefore, this study provides theoretical evidence for future chemical and genetic regulation of lignin biosynthesis in crop plants to reduce Cd accumulation.
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Affiliation(s)
- Qin Dong
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Yingjie Wu
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China.
| | - Haidong Wang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Bing Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Rong Huang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Huanxiu Li
- College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China
| | - Qi Tao
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Qiquan Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Xiaoyan Tang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Qiang Xu
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Youlin Luo
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Changquan Wang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China.
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Lin L, Wu X, Deng X, Lin Z, Liu C, Zhang J, He T, Yi Y, Liu H, Wang Y, Sun W, Xu Z. Mechanisms of low cadmium accumulation in crops: A comprehensive overview from rhizosphere soil to edible parts. Environ Res 2024; 245:118054. [PMID: 38157968 DOI: 10.1016/j.envres.2023.118054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/19/2023] [Accepted: 12/25/2023] [Indexed: 01/03/2024]
Abstract
Cadmium (Cd) is a toxic heavy metal often found in soil and agricultural products. Due to its high mobility, Cd poses a significant health risk when absorbed by crops, a crucial component of the human diet. This absorption primarily occurs through roots and leaves, leading to Cd accumulation in edible parts of the plant. Our research aimed to understand the mechanisms behind the reduced Cd accumulation in certain crop cultivars through an extensive review of the literature. Crops employ various strategies to limit Cd influx from the soil, including rhizosphere microbial fixation and altering root cell metabolism. Additional mechanisms include membrane efflux, specific transport, chelation, and detoxification, facilitated by metalloproteins such as the natural resistance-associated macrophage protein (Nramp) family, heavy metal P-type ATPases (HMA), zinc-iron permease (ZIP), and ATP-binding cassette (ABC) transporters. This paper synthesizes differences in Cd accumulation among plant varieties, presents methods for identifying cultivars with low Cd accumulation, and explores the unique molecular biology of Cd accumulation. Overall, this review provides a comprehensive resource for managing agricultural lands with lower contamination levels and supports the development of crops engineered to accumulate minimal amounts of Cd.
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Affiliation(s)
- Lihong Lin
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Xinyue Wu
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Xingying Deng
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Zheng Lin
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Chunguang Liu
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin, 300350, China
| | - Jiexiang Zhang
- GRG Metrology& Test Group Co., Ltd., Guangzhou, 510656, China
| | - Tao He
- College of Chemical and Environmental Engineering, Hanjiang Normal University, Shiyan, 442000, China
| | - Yunqiang Yi
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Hui Liu
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Yifan Wang
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Weimin Sun
- Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Zhimin Xu
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China.
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Sun X, Tang Z, Zheng G, Du H, Li P. Effects of different cellular and subcellular characteristics on the atmospheric Pb uptake, distribution and morphology in Tillandsia usneoides leaves. Plant Physiol Biochem 2024; 207:108400. [PMID: 38295526 DOI: 10.1016/j.plaphy.2024.108400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 01/24/2024] [Indexed: 02/02/2024]
Abstract
Lead (Pb) is a widespread highly toxic and persistent environmental pollutant. Plant leaves play a key role in accumulating atmospheric Pb, but its distribution in different cells and subcellular structures and the factors affecting it have been little studied. Here, Tillandsia usneoides, an indicator plant for atmospheric heavy metals, was treated with an aerosol generation device to analyze Pb contents in different cells (three types of cells in leaf surface scales, epidermal cells, mesophyll cells, vascular bundle cells), subcellular structures (cell wall, cell membrane, vacuoles, and organelles) and cell wall components (pectin, hemicellulose 1 and 2, and cellulose). Results show the different cells of T. usneoides leaves play distinct roles in the process of Pb retention. The outermost wing cells are structures that capture external pollutants, while mesophyll cells, as the aggregation site after material transport, ring cells, disc cells, epidermal cells, and vascular cells are material transporters. Pb was only detected in the cell wall and pectin, indicating the cell wall was the dominant subcellular structure for Pb retention, while pectin was the main component affecting Pb retention. FTIR analysis of cell wall components indicated the esterified carboxyl (CO) functional group in pectin may function in absorbing Pb. Pb entered leaf cells mainly in the form of low toxicity and activity to enhance its resistance.
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Affiliation(s)
- Xingyue Sun
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China; Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Zhen Tang
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China
| | - Guiling Zheng
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China
| | - Hongxia Du
- Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Peng Li
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China.
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Ahmad J, Yasmeen R, Irfan M, Al-Huqail AA, Qureshi MI. Assessment of health risk, genotoxicity, and thiol compounds in Trigonella foenum-graecum (Fenugreek) under arsenic stress. Environ Sci Pollut Res Int 2023; 30:884-898. [PMID: 35907074 DOI: 10.1007/s11356-022-22269-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
Arsenic (As) traces have been reported worldwide in vegetables and crops cultivated in As-polluted soils. Being carcinogenic, the presence of As in edibles is of great concern as it ultimately reaches humans and animals through the food chain. Besides, As toxicity adversely affects the growth, physiology, metabolism, and productivity of crops. In the present study, Trigonella foenum-graecum (Fenugreek) was exposed to the As stress (0, 50, 100, and 150 μM sodium arsenate) for a week. Further, evaluation of As accumulation in roots and shoots, magnitude and visualization of oxyradicals, and thiol-based defence offered by Fenugreek was assessed. The root and leaf accumulated 258-453 μg g-1 dry wt (DW) and 81.4-102.1 μg g-1 DW of As, respectively. An arsenic-mediated decline in the growth index and increase in oxidative stress was noted. Arsenic stress modulated the content of thiol compounds; especially cysteine content increased from 0.36 to 0.43 µmole g-1 FW protein was noted. Random Amplified Polymorphic DNA (RAPD)-based analysis showed DNA damage in As-treated plants. Health risk assessment parameters showed that As concentration in the consumable plant shoot was below the critical hazard level (hazard quotient < 1). Moreover, T. foenum-graecum showed varied responses to As-induced oxidative stress with applied concentrations (150 μM being more toxic than lower concentrations). In addition, the RAPD profile and level of thiol compounds were proved significant biomarkers to assess the As toxicity in plants. The conclusion of this study will help users of fenugreek to have a clue and create awareness regarding the consumption.
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Affiliation(s)
- Javed Ahmad
- Department of Biotechnology, Jamia Millia Islamia, New Delhi, 110 025, India
| | - Rubina Yasmeen
- Department of Biotechnology, Jamia Millia Islamia, New Delhi, 110 025, India
| | - Mohammad Irfan
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Asma A Al-Huqail
- Chair of Climate Change, Environmental Development and Vegetation Cover, Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
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Dong Q, Tao Q, Li B, Huang R, Xu Q, Li H, Shen J, Chen X, Li Q, Tang X, Kačík F, Kováč J, Ďurkovič J, Wu Y, Wang C. The mechanism of enhanced lignin regulating foliar Cd absorption and yield in rice (Oryza sativa L.). Ecotoxicol Environ Saf 2023; 249:114481. [PMID: 38321693 DOI: 10.1016/j.ecoenv.2022.114481] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/20/2022] [Accepted: 12/24/2022] [Indexed: 02/08/2024]
Abstract
The impact of atmospheric deposition of cadmium (Cd) in cereal crops has become a global concern. Enhanced lignin content was expected to benefit the plant performance against Cd exposure. To date, however, the underlying mechanisms of lignin regulating foliar Cd absorption in rice (Oryza sativa L.) and its effect on grain yield remains unclear. In present study, the effect and mechanism of rice in response to leaf Cd exposure were investigated using 113Cd stable isotope and a lignin-increased rice mutant. The highest Cd uptake efficiency and uptake amount was observed in wild type (WT) plant grown in the maturity period, which were 3-fold higher than in mutant plant. Compared to WT, the mutant exhibited 14.75% and 25.43% higher contents in G- and S-unit of lignin monomers. Lignin biosynthesis and polymerization related genes (OsPAL/OsCOMT/Os4CL3/OsLAC5/OsLAC15) were significantly up-regulated in mutants. In addition, the enzyme activities involved in the above process were also significantly increased by 1.24-1.49-fold. The increased Cd retention in cell wall and decreased gene expression levels of OsNRAMP5, OsHMA3 and OsIRT1 in mutant indicated that lignin effectively inhibited Cd transportion in plant tissues. Moreover, the antioxidant capacity and photosynthesis efficiency in mutant plant were obviously improved, leading to higher Cd tolerance and increased grain yield. Our results revealed the molecular and physiological mechanisms of enhanced lignin regulating foliar Cd absorption and yield in rice, and provided the valuable rice genotype to ensure food safety.
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Affiliation(s)
- Qin Dong
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Qi Tao
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Bing Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Rong Huang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Qiang Xu
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Huanxiu Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Jie Shen
- China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Xi Chen
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Qiquan Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Xiaoyan Tang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - František Kačík
- Department of Chemistry and Chemical Technologies, Technical University in Zvolen, 96001 Zvolen, Slovakia
| | - Ján Kováč
- Department of Phytology, Technical University in Zvolen, 96001 Zvolen, Slovakia
| | - Jaroslav Ďurkovič
- Department of Phytology, Technical University in Zvolen, 96001 Zvolen, Slovakia
| | - Yingjie Wu
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China.
| | - Changquan Wang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China.
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Aleamotuʻa M, Baker JK, McCurdy DW, Collings DA. Phi thickenings in Brassica oleracea roots are induced by osmotic stress and mechanical effects, both involving jasmonic acid. J Exp Bot 2022; 73:756-769. [PMID: 34677585 DOI: 10.1093/jxb/erab468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Phi thickenings are peculiar secondary cell wall thickenings found in radial walls of cortical cells in plant roots. However, while thickenings are widespread in the plant kingdom, research into their development has been lacking. Here, we describe a simple system for rapid induction of phi thickenings in primary roots of Brassica. Four-day-old seedlings were transferred from control agar plates to new plates containing increased levels of osmotica. Phi thickening development occurred within a narrow region of the differentiation zone proportional to osmolarity, with cellulose deposition and lignification starting after 12h and 15h, respectively. However, osmoprotectants not only failed to induce phi thickenings, but inhibited induction when tested in combination with thickening-inducing osmotica. An independent, biomechanical pathway exists regulating phi thickening induction, with root growth rates and substrate texture being important factors in determining thickening induction. Phi thickening development is also controlled by stress-related plant hormones, most notably jasmonic acid, but also abscisic acid. Our research not only provides the first understanding of the developmental pathways controlling phi thickening induction, but also provides tools with which the functions of these enigmatic structures might be clarified.
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Affiliation(s)
- Maketalena Aleamotuʻa
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Jaime K Baker
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - David W McCurdy
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - David A Collings
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
- Harry Butler Institute, Murdoch University, Murdoch, WA 6150, Australia
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
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Wu D, Li L, Li C, Dun B, Zhang J, Li T, Zhou C, Tan D, Yang C, Huang G, Zhang X. Apoplastic histochemical features of plant root walls that may facilitate ion uptake and retention. Open Life Sci 2022; 16:1347-1356. [PMID: 35071769 PMCID: PMC8749128 DOI: 10.1515/biol-2021-0137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/28/2021] [Accepted: 11/07/2021] [Indexed: 11/18/2022] Open
Abstract
We used brightfield and epifluorescence microscopy, as well as permeability tests, to investigate the apoplastic histochemical features of plant roots associated with ion hyperaccumulation, invasion, and tolerance of oligotrophic conditions. In hyperaccumulator species with a hypodermis (exodermis absent), ions penetrated the root apex, including the root cap. By contrast, in non-hyperaccumulator species possessing an exodermis, ions did not penetrate the root cap. In vivo, the lignified hypodermis blocked the entry of ions into the cortex, while root exodermis absorbed ions and restricted them to the cortex. The roots of the hyperaccumulators Pteris vittata and Cardamine hupingshanensis, as well as the aquatic invasives Alternanthera philoxeroides, Eichhornia crassipes, and Pistia stratiotes, contained lignin and pectins. These compounds may trap and store ions before hypodermis maturation, facilitating ion hyperaccumulation and retention in the apoplastic spaces of the roots. These apoplastic histochemical features were consistent with certain species-specific characters, including ion hyperaccumulation, invasive behaviors in aquatic environments, or tolerance of oligotrophic conditions. We suggest that apoplastic histochemical features of the root may act as invasion mechanisms, allowing these invasive aquatic plants to outcompete indigenous plants for ions.
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Affiliation(s)
- Di Wu
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Linbao Li
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Chengdao Li
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Bicheng Dun
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Jun Zhang
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Ten Li
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
| | - Cunyu Zhou
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
| | - Debao Tan
- Changjiang River Scientific Research Institute, Wuhan, Hubei 430010, China
| | - Chaodong Yang
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
| | - Guiyun Huang
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Xia Zhang
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
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Guo C, Mei R, Anwar M, Zhao D, Lan C, Jiang Y, Zhuang J, Wang C, Hu Z. The Functionally Characterization of Putative Genes Involved in the Formation of Mannose in the Aplanospore Cell Wall of Haematococcus pluvialis (Volvocales, Chlorophyta). Metabolites 2021; 11:725. [PMID: 34822383 DOI: 10.3390/metabo11110725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 11/23/2022] Open
Abstract
Unicellular volvocalean green algal Haematococcus pluvialis, known as astaxanthin rich microalgae, transforms into aplanospore stage from the flagellate stage when exposed to the stress environments. However, the mechanism of the formation of aplanospore cell wall, which hinders the extraction of astaxanthin and the genetic manipulation is still unclear. In this study, the cell wall components under salicylic acid and high light stresses were explored, and cellulose was considered the main component in the flagellates, which changed gradually into mannose in the aplanospore stages. During the period, the genes related to the cellulose and mannose metabolisms were identified based on the RNA-seq data, which presented a similar expression pattern. The positive correlations were observed among these studied genes by Pearson Correlation (PC) analysis, indicating the coordination between pathways of cellulose and mannose metabolism. The study firstly explored the formation mechanism of aplanospore cell wall, which might be of scientific significance in the study of H. pluvialis.
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Idris NA, Aleamotuʻa M, McCurdy DW, Collings DA. The Orchid Velamen: A Model System for Studying Patterned Secondary Cell Wall Development? Plants (Basel) 2021; 10:1358. [PMID: 34371560 DOI: 10.3390/plants10071358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 11/17/2022]
Abstract
Understanding the mechanisms through which plants generate secondary cell walls is of more than academic interest: the physical properties of plant-derived materials, including timber and textiles, all depend upon secondary wall cellulose organization. Processes controlling cellulose in the secondary cell wall and their reliance on microtubules have been documented in recent decades, but this understanding is complicated, as secondary walls normally form in the plant’s interior where live cell imaging is more difficult. We investigated secondary wall formation in the orchid velamen, a multicellular epidermal layer found around orchid roots that consists of dead cells with lignified secondary cell walls. The patterns of cell wall ridges that form within the velamen vary between different orchid species, but immunolabelling demonstrated that wall deposition is controlled by microtubules. As these patterning events occur at the outer surface of the root, and as orchids are adaptable for tissue culture and genetic manipulation, we conclude that the orchid root velamen may indeed be a suitable model system for studying the organization of the plant cell wall. Notably, roots of the commonly grown orchid Laelia anceps appear ideally suited for developing this research.
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Guo X, Luo J, Du Y, Li J, Liu Y, Liang Y, Li T. Coordination between root cell wall thickening and pectin modification is involved in cadmium accumulation in Sedum alfredii. Environ Pollut 2021; 268:115665. [PMID: 33010543 DOI: 10.1016/j.envpol.2020.115665] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/17/2020] [Accepted: 09/12/2020] [Indexed: 06/11/2023]
Abstract
Root cell wall (RCW) modification is a widespread important defense strategy of plant to cope with trace metals. However, mechanisms underlying its remolding in cadmium (Cd) accumulation are still lacking in hyperaccumulators. In this study, changes of RCW structures and components between nonhyperaccumulating ecotype (NHE) and hyperaccumulating ecotype (HE) of Sedum alfredii were investigated simultaneously. Under 25 μM Cd treatment, RCW thickness of NHE is nearly 2 folds than that of HE and the thickened cell wall of NHE was enriched in low-methylated pectin, leading to more Cd trapped in roots tightly. In the opposite, large amounts of high-methylated pectin were assembled around RCW of HE with Cd supply, in this way, HE S. alfredii decreased its root fixation of Cd and enhanced Cd migration into xylem. TEM and AFM results further confirmed that thickened cell wall was caused by the increased amounts of cellulose and lignin while root tip lignification was resulted from variations of sinapyl (S) and guaiacyl (G) monomers. Overall, thickened cell wall and methylated pectin have synchronicity in spatial location of roots, and their coordination contributed to Cd accumulation in S. alfredii.
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Affiliation(s)
- Xinyu Guo
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jipeng Luo
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yilin Du
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jinxing Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yuankun Liu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yongchao Liang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Tingqiang Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou, 310058, China; National Demonstration Center for Experimental Environment and Resources Education, Zhejiang University, Hangzhou, 310058, China.
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11
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Idris NA, Collings DA. The Induction and Roles Played by Phi Thickenings in Orchid Roots. Plants (Basel) 2019; 8:E574. [PMID: 31817554 DOI: 10.3390/plants8120574] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/30/2019] [Accepted: 12/02/2019] [Indexed: 11/23/2022]
Abstract
Phi thickenings are specialised secondary wall thickenings present in the root cortex of many plant species, including both angiosperms and gymnosperms. While environmental stresses induce phi thickenings, their role(s) in the root remain unclear. Suggested functions include regulation of transport through the apoplast in a manner similar to the Casparian strip, limiting fungal infections, and providing mechanical support to the root. We investigated phi thickening induction and function in Miltoniopsis sp., an epiphytic orchid. As movement of a fluorescent tracer through the apoplast was not blocked by phi thickenings, and as phi thickenings developed in the roots of sterile cultures in the absence of fungus and did not prevent fungal colonisation of cortical cells, the phi thickenings in Miltoniopsis did not function as a barrier. Phi thickenings, absent in roots grown on agar, remained absent when plants were transplanted to moist soil, but were induced when plants were transplanted to well-drained media, and by the application of water stress. We suggest that it is likely that phi thickenings stabilise to the root during water stress. Nevertheless, the varied phi thickening induction responses present in different plant species suggest that the phi thickenings may play multiple adaptive roles depending on species.
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