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Auxin acts upstream of nitric oxide to regulate cell wall xyloglucan and its aluminium-binding capacity in Arabidopsis thaliana. PLANTA 2024; 259:52. [PMID: 38289400 DOI: 10.1007/s00425-024-04331-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024]
Abstract
MAIN CONCLUSION Auxin acts upstream of NO through NOA and XXT5 pathways to regulate the binding capacity of the root cell wall to Al. In our previous study, we identified an unknown mechanism by which 1-naphthaleneacetic acid (NAA) decreased the fixation of aluminum (Al) in the cell wall. Here, we observed that external application of the nitric oxide (NO) donor S-nitrosoglutathion (GSNO) increased the inhibition of Al on root elongation. Further analysis indicated that GSNO could induce Al accumulation in the roots and root cell walls, which is consistent with lower xyloglucan content. In comparison to the Columbia-0 (Col-0) wild type (WT), endogenous NO-reduced mutants noa1 (NOA pathway) and nia1nia2 (NR pathway) were more resistant to Al, with lower root Al content, higher xyloglucan content, and more Al accumulation in the root cell walls. By contrast, the xxt5 mutant with reduced xyloglucan content exhibited an Al-sensitive phenotype. Interestingly, Al treatment increased the endogenous auxin and NO levels, and the auxin levels induced under Al stress further stimulated NO production. Auxin application reduced Al retention in hemicellulose and decreased the xyloglucan content, similar to the effects observed with GSNO. In yucca and aux1-7 mutants, exogenous application of NO resulted in responses similar to those of the WT, whereas exogenous auxin had little effect on the noa1 mutant under Al stress. In addition, as auxin had similar effects on the nia1nia2 mutant and the WT, exogenous auxin and NO had little effect on the xxt5 mutant under Al stress, further confirming that auxin acts upstream of NO through NOA and XXT5 pathways to regulate the binding capacity of the root cell wall to Al.
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Genome-wide profiling of genetic variations reveals the molecular basis of aluminum stress adaptation in Tibetan wild barley. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132541. [PMID: 37716271 DOI: 10.1016/j.jhazmat.2023.132541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/17/2023] [Accepted: 09/11/2023] [Indexed: 09/18/2023]
Abstract
Aluminum (Al) toxicity in acidic soil is a major factor affecting crop productivity. The extensive genetic diversity found in Tibetan wild barley germplasms offers a valuable reservoir of alleles associated with aluminum tolerance. Here, resequencing of two Al-tolerant barley genotypes (Tibetan wild barley accession XZ16 and cultivated barley Dayton) identified a total of 19,826,182 and 16,287,277 single nucleotide polymorphisms (SNPs), 1628,052 and 1386,973 insertions/deletions (InDels), 61,532 and 57,937 structural variations (SVs), 248,768 and 240,723 copy number variations (CNVs) in XZ16 and Dayton, respectively, and uncovered approximately 600 genes highly related to Al tolerance in barley. Comparative genomic analyses unveiled 71 key genes that contain unique genetic variants in XZ16 and are predominantly associated with organic acid exudation, Al sequestration, auxin response, and transcriptional regulation. Manipulation of these key genes at the genetic and transcriptional level is a promising strategy for developing optimal haplotype combinations and new barley cultivars with improved Al tolerance. This study represents the first comprehensive examination of genetic variation in Al-tolerant Tibetan wild barley through genome-wide profiling. The obtained results make the deep insight into the mechanisms underlying barley adaptation to Al toxicity, and identified the candidate genes useful for improvement of Al tolerance in barley.
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Comparative Transcriptome Profiling Reveals Key MicroRNAs and Regulatory Mechanisms for Aluminum Tolerance in Olive. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12050978. [PMID: 36903838 PMCID: PMC10005091 DOI: 10.3390/plants12050978] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 02/18/2023] [Accepted: 02/19/2023] [Indexed: 06/06/2023]
Abstract
Aluminum toxicity (Al) is one of the major constraints to crop production in acidic soils. MicroRNAs (miRNAs) have emerged as key regulatory molecules at post-transcriptional levels, playing crucial roles in modulating various stress responses in plants. However, miRNAs and their target genes conferring Al tolerance are poorly studied in olive (Olea europaea L.). Here, genome-wide expression changes in miRNAs of the roots from two contrasting olive genotypes Zhonglan (ZL, Al-tolerant) and Frantoio selezione (FS, Al-sensitive) were investigated by high-throughput sequencing approaches. A total of 352 miRNAs were discovered in our dataset, consisting of 196 conserved miRNAs and 156 novel miRNAs. Comparative analyses showed 11 miRNAs have significantly different expression patterns in response to Al stress between ZL and FS. In silico prediction identified 10 putative target gene of these miRNAs, including MYB transcription factors, homeobox-leucine zipper (HD-Zip) proteins, auxin response factors (ARF), ATP-binding cassette (ABC) transporters and potassium efflux antiporter. Further functional classification and enrichment analysis revealed these Al-tolerance associated miRNA-mRNA pairs are mainly involved in transcriptional regulation, hormone signaling, transportation and metabolism. These findings provide new information and perspectives into the regulatory roles of miRNAs and their target for enhancing Al tolerance in olives.
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Identification and functional characterization of the xyloglucan endotransglucosylase/hydrolase 32 (AhXTH32) in peanut during aluminum-induced programmed cell death. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 194:161-168. [PMID: 36410145 DOI: 10.1016/j.plaphy.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
The toxicity of aluminum (Al) in acidic soil is a prevalent problem and causes reduced crop yields. In the plant response to Al toxicity, programmed cell death (PCD) appears to be an important mechanism. The plant cell wall of crop roots is the predominant site targeted by Al. Here, studies of the capacities of different cell wall constituents (pectin, hemicellulose 1 {HC1} and HC2) to adsorb Al indicated that HC1 has the greater ability to bind Al. The activity of xyloglucan endotransglucosylase (XET) was significantly inhibited by Al in the Al-tolerant peanut cultivar '99-1507' compared to that in 'ZH 2' (Al-sensitive). Results from qPCR analysis suggested that the suppression of XET activity by Al was transcriptionally regulated and that xyloglucan endotransglucosylase/hydrolase 32 (AhXTH32) was the major contributor to these changes. The overexpression of AhXTH32 in Arabidopsis strongly inhibited root growth with a loss of viability in root cells and the occurrence of typical hallmarks of PCD, while largely opposite effects were observed after xth32 suppression. AhXTH32 contributed to the modulation XET and xyloglucan endohydrolase (XEH) activity in vivo. Taken together, our results demonstrate that Al-tolerant peanut cultivar root tips cell walls bind Al predominantly in the HC1 fraction, which results in the inhibition of AhXTH32, with consequences to root growth, Al sensitivity, the occurrence of PCD and the XET/XEH activity ratio.
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Biochemistry and transcriptome analyses reveal key genes and pathways involved in high- aluminum stress response and tolerance in hydrangea sepals. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 185:268-278. [PMID: 35724621 DOI: 10.1016/j.plaphy.2022.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/05/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Hydrangea [Hydrangea macrophylla (Thunb.) Ser.] is a high aluminum-tolerant ornamental plant species, which has a specific characteristic of color change, ie. some cultivars' floral color will change from red to blue or blue-violet planted in acidic soil containing aluminum. This study aims to understand the complex molecular mechanisms of floral color change under Al stress, through comparative biochemistry and transcriptome analyses between an Al3+-sensitive cultivar 'Bailer' and insensitive cultivar 'Ruby' under Al-stress. The results of biochemistry analysis showed that 'Bailer' displayed higher contents of Al3+ and delphinium-3-O-glucoside than that of 'Ruby' after Al2(SO4)3 treating. Meanwhile, the transcriptome analysis of different tissues identified 12,321 differentially expressed genes (DEGs) in 'Bailer' and 6,703 in 'Ruby'. Transcriptome analysis showed that changes in genes' expression pattern in several genes and pathways [such as including metal transporters, reactive oxygen species (ROS) scavenging enzyme, plant hormone signal transduction and favonoid biosynthesis pathway] were the key contributors to the Al3+-sensitive cultivar 'Bailer'. Besides, gene co-expression network analysis (WGCNA) demonstrated that five hub genes, including ABC transporters (TRINITY_DN1053_c0_g1, TRINITY_DN3377_c0_g2), cationic amino acid transporter (TRINITY_DN9684_c0_g2), oligopeptide transporter (TRINITY_DN1147_c0_g2) and flavonol synthase (TRINITY_DN15902_c0_g1), played vital roles in the networks regulating Al tolerance in hydrangea. Furthermore, HmABCI17's (TRINITY_DN1053_c0_g1) expression enhanced Al tolerance in yeast. The conclusions of this study are helpful to elucidate the differences and molecular mechanisms of different hydrangea cultivars on Al tolerance, and provide new insights into molecular assisted-screening for breeding blue flowers in hydrangea and other ornamental plants.
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Arabidopsis ETHYLENE INSENSITIVE 3 directly regulates the expression of PG1β-like family genes in response to aluminum stress. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4923-4940. [PMID: 35661874 DOI: 10.1093/jxb/erac161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
The genes in the subfamily PG1β (beta subunit of poly-galacturonase isoenzyme 1) have a clear effect on the biosynthesis pathway of pectin, a main component of the cell wall. However, the detailed functions of the PG1β-like gene members in Arabidopsis (AtPG1-3) have not yet been determined. In this study, we investigated their functional roles in response to aluminum (Al) stress. Our results indicate that the PG1β-like gene members are indeed involved in the Al-stress response and they can modulate its accumulation in roots to achieve optimum root elongation and hence better seedling growth. We found that transcription factor EIN3 (ETHYLENE INSENSITIVE 3) alters pectin metabolism and the EIN3 gene responds to Al stress to affect the pectin content in the root cell walls, leading to exacerbation of the inhibition of root growth, as reflected by the phenotypes of overexpressing lines. We determined that EIN3 can directly bind to the promoter regions of PG1-3, which act downstream of EIN3. Thus, our results show that EIN3 responds to Al stress in Arabidopsis directly through regulating the expression of PG1-3. Hence, EIN3 mediates their functions by acting as a biomarker in their molecular biosynthesis pathways, and consequently orchestrates their biological network in response to Al stress.
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Different antioxidant regulation mechanisms in response to aluminum-induced oxidative stress in Eucalyptus species. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 241:113748. [PMID: 35696965 DOI: 10.1016/j.ecoenv.2022.113748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 05/17/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Forest ecosystems play an important role in environmental protection and maintaining ecological balance. Understanding the physiological mechanisms of tree species response to aluminum (Al) toxic is crucial to reveal the main causes of plantation decline in acid rain area. As an important afforestation tree species in tropical and subtropical areas, Eucalyptus has high economic value and plays crucial ecological roles. However, continuous fertilization and acid precipitation can exacerbate soil acidification and increase soil active Al, which has a significant negative impact on Eucalyptus growth. Hence, species and genotypes with high Al resistance are required to solve the problem of Al toxicity of acidic soils for sustainable forest production. In this study, E. urophylla was better adapted to Al stress than E. grandis or E. tereticornis; its high Al resistance was attributed to greater antioxidant enzyme activity and non-enzymatic antioxidant content, and a lower degree of membrane lipid peroxidation than E. grandis or E. tereticornis. The differences in adaptability among the three pure species were attributed to their distinct habitats. Eucalyptus urophylla × E. grandis inherited the outstanding adaptability to Al stress from its maternal species (E. urophylla), indicating that Al tolerance is highly heritable and can be selected in Eucalyptus breeding. Our results indicated that the response of Eucalyptus to Al stress may fluctuate according to the time under stress, and might be related to dynamic changes in ROS elimination and accumulation.
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GsERF1 enhances Arabidopsis thaliana aluminum tolerance through an ethylene-mediated pathway. BMC PLANT BIOLOGY 2022; 22:258. [PMID: 35610574 PMCID: PMC9128276 DOI: 10.1186/s12870-022-03625-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 05/04/2022] [Indexed: 05/09/2023]
Abstract
Ethylene response factor (ERF) transcription factors constitute a subfamily of the AP2/ERF superfamily in plants and play multiple roles in plant growth and development as well as in stress responses. In this study, the GsERF1 gene from the wild soybean BW69 line (an Al-resistant Glycine soja line) was rapidly induced in response to aluminum stress. Quantitative real-time PCR (qRT-PCR) analysis showed that the GsERF1 gene maintained a constitutive expression pattern and was induced in soybean in response to aluminum stress, with increased amounts of transcripts detected in the roots. The putative GsERF1 protein, which contains an AP2 domain, was located in the nucleus and maintained transactivation activity. In addition, under AlCl3 treatment, GsERF1 overexpression increased the relative growth rate of the roots of Arabidopsis and weakened the hematoxylin staining of hairy roots. Ethylene synthesis-related genes such as ACS4, ACS5 and ACS6 were upregulated in GsERF1 transgenic lines compared with the wild type under AlCl3 treatment. Furthermore, the expression levels of stress/ABA-responsive marker genes, including ABI1, ABI2, ABI4, ABI5 and RD29B, in the GsERF1 transgenic lines were affected by AlCl3 treatment, unlike those in the wild type. Taken together, the results indicated that overexpression of GsERF1 may enhance aluminum tolerance of Arabidopsis through an ethylene-mediated pathway and/or ABA signaling pathway, the findings of which lay a foundation for breeding soybean plants tolerant to aluminum stress.
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Grants
- 2016ZX08004002-007 the Major Project of New Varieties Cultivation of Genetically Modified Organisms
- 2016ZX08004002-007 the Major Project of New Varieties Cultivation of Genetically Modified Organisms
- 2016ZX08004002-007 the Major Project of New Varieties Cultivation of Genetically Modified Organisms
- 2016ZX08004002-007 the Major Project of New Varieties Cultivation of Genetically Modified Organisms
- 2016ZX08004002-007 the Major Project of New Varieties Cultivation of Genetically Modified Organisms
- 2016ZX08004002-007 the Major Project of New Varieties Cultivation of Genetically Modified Organisms
- 2016ZX08004002-007 the Major Project of New Varieties Cultivation of Genetically Modified Organisms
- 31771816, 31971965 the National Natural Science Foundation of China
- 31771816, 31971965 the National Natural Science Foundation of China
- 31771816, 31971965 the National Natural Science Foundation of China
- 31771816, 31971965 the National Natural Science Foundation of China
- 31771816, 31971965 the National Natural Science Foundation of China
- 31771816, 31971965 the National Natural Science Foundation of China
- 31771816, 31971965 the National Natural Science Foundation of China
- 4100-C17106, 21301091702101 the Special Supervision on Quality and Safety of Agricultural Products of the Ministry of Agriculture and Rural Areas
- 4100-C17106, 21301091702101 the Special Supervision on Quality and Safety of Agricultural Products of the Ministry of Agriculture and Rural Areas
- 4100-C17106, 21301091702101 the Special Supervision on Quality and Safety of Agricultural Products of the Ministry of Agriculture and Rural Areas
- 4100-C17106, 21301091702101 the Special Supervision on Quality and Safety of Agricultural Products of the Ministry of Agriculture and Rural Areas
- 4100-C17106, 21301091702101 the Special Supervision on Quality and Safety of Agricultural Products of the Ministry of Agriculture and Rural Areas
- 4100-C17106, 21301091702101 the Special Supervision on Quality and Safety of Agricultural Products of the Ministry of Agriculture and Rural Areas
- 4100-C17106, 21301091702101 the Special Supervision on Quality and Safety of Agricultural Products of the Ministry of Agriculture and Rural Areas
- 2018YFE0116900 the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
- 2018YFE0116900 the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
- 2018YFE0116900 the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
- 2018YFE0116900 the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
- 2018YFE0116900 the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
- 2018YFE0116900 the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
- 2018YFE0116900 the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
- CARS-04-PS09 the China Agricultural Research System
- CARS-04-PS09 the China Agricultural Research System
- CARS-04-PS09 the China Agricultural Research System
- CARS-04-PS09 the China Agricultural Research System
- CARS-04-PS09 the China Agricultural Research System
- CARS-04-PS09 the China Agricultural Research System
- CARS-04-PS09 the China Agricultural Research System
- 2020B020220008 the Key-Area Research and Development Program of Guangdong Province
- 2020B020220008 the Key-Area Research and Development Program of Guangdong Province
- 2020B020220008 the Key-Area Research and Development Program of Guangdong Province
- 2020B020220008 the Key-Area Research and Development Program of Guangdong Province
- 2020B020220008 the Key-Area Research and Development Program of Guangdong Province
- 2020B020220008 the Key-Area Research and Development Program of Guangdong Province
- 2020B020220008 the Key-Area Research and Development Program of Guangdong Province
- 201804020015 the Project of Science and Technology of Guangzhou
- 201804020015 the Project of Science and Technology of Guangzhou
- 201804020015 the Project of Science and Technology of Guangzhou
- 201804020015 the Project of Science and Technology of Guangzhou
- 201804020015 the Project of Science and Technology of Guangzhou
- 201804020015 the Project of Science and Technology of Guangzhou
- 201804020015 the Project of Science and Technology of Guangzhou
- the Key Projects of International Scientific and Technological Innovation Cooperation among Governments under National Key R & D Plan
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Morpho-physiological characterization coupled with expressional accord of exclusion mechanism in wild and cultivated lentil under aluminum stress. PROTOPLASMA 2021; 258:1029-1045. [PMID: 33598755 DOI: 10.1007/s00709-021-01619-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
Aluminum stress deteriorates lentil production under acidic soils. Enhanced insight into Al tolerance traits is needed to improve its productivity. Therefore, Al-resistant (L-4602, PAL-8) and Al-sensitive (BM-4, EC-223229) cultivars along with a resistant wild (ILWL-15) were characterized for morpho-physiological traits viz. seedling root architecture (SRA), Al accumulation, and localization via fluorescent and non-fluorescent staining under control and Al-treated conditions. Also, antioxidant activities and organic acid secretion were quantified, and expressions of 10 associated genes were analyzed. Roots of Al-resistant cultivars and wild genotype showed higher root growth, antioxidant enzyme activities, and organic acid secretion than Al-sensitive ones. Among these traits, higher organic acid secretion was influenced by enhanced expression of genes, especially-aluminum sensitive-3 (ALS 3), aluminum-activated malate transporter (ALMT), multidrug and toxic compound extrusion (MATE), citrate synthase (CS), and phospho enol pyruvate carboxylase (PEPC)-which helped in reducing Al and callose accumulation. These genes were located on lentil chromosomes via sequence alignment with lentil draft genome. A strong link between morpho-physiological variation and organic acid secretion was noted which reinforced the prominence of exclusion mechanism. It was complemented by enhanced antioxidant activities at seedling stage which mitigated Al stress effects on SRA. Wild outperformed over cultivars indicating its impregnable evolution which can be exploited to better understand tolerance mechanisms. Al-resistant cultivars had significantly higher seed yield than Al-sensitive and national checks on Al-toxic fields, confirming-tolerance is sustained till reproductive stage in lentil. This study elucidated role of gene families in eliminating Al toxicity that will assist breeders to formulate strategies for developing Al-resistant cultivars.
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Transcriptome analysis reveals significant difference in gene expression and pathways between two peanut cultivars under Al stress. Gene 2021; 781:145535. [PMID: 33631240 DOI: 10.1016/j.gene.2021.145535] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 12/31/2022]
Abstract
Aluminum (Al) toxicity is an important factor in limiting peanut growth on acidic soil. The molecular mechanisms underlying peanut responses to Al stress are largely unknown. In this study, we performed transcriptome analysis of the root tips (0-1 cm) of peanut cultivar ZH2 (Al-sensitive) and 99-1507 (Al-tolerant) respectively. Root tips of peanuts that treated with 100 μM Al for 8 h and 24 h were analyzed by RNA-Seq, and a total of 8,587 differentially expressed genes (DEGs) were identified. GO and KEGG pathway analysis excavated a group of important Al-responsive genes related to organic acid transport, metal cation transport, transcription regulation and programmed cell death (PCD). These homologs were promising targets to modulate Al tolerance in peanuts. It was found that the rapid transcriptomic response to Al stress in 99-1507 helped to activate effective Al tolerance mechanisms. Protein and protein interaction analysis indicated that MAPK signal transduction played important roles in the early response to Al stress in peanuts. Moreover, weighted correlation network analysis (WGCNA) identified a predicted EIL (EIN3-like) gene with greatly increased expression as an Al-associated gene, and revealed a link between ethylene signaling transduction and Al resistance related genes in peanut, which suggested the enhanced signal transduction mediated the rapid transcriptomic responses. Our results revealed key pathways and genes associated with Al stress, and improved the understanding of Al response in peanut.
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Protective roles of salicylic acid in maintaining integrity and functions of photosynthetic photosystems for alfalfa (Medicago sativa L.) tolerance to aluminum toxicity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 155:570-578. [PMID: 32846392 DOI: 10.1016/j.plaphy.2020.08.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
Aluminum (Al) can be detrimental to plant growth in areas with Al contamination. The objective of this study was to determine whether salicylic acid (SA) can improve plant tolerance to Al stress by mitigating Al toxicity for chloroplasts and photosynthetic systems in alfalfa (Medicago sativa L.). Plants were treated with Al (100 μM) for 3 d in a hydroponic system. The content of Al increased in leaves treated with Al, resulting in damage and deformation of chloroplasts. In Al-damaged leaves, chloroplast envelopes and starch granules disappeared; the lamellae and stroma lamella were loosely arranged and indistinguishable, and the number of grana was reduced; a large number of small plastoglobules appeared. Foliar spraying of 15 μM SA reduced Al content in roots and leaves and alleviated Al damages in chloroplasts. With 15 μM SA treatments, the chloroplast shape returned to a flat ellipsoid, thylakoids were arranged closely and regularly, chloroplasts had intact starch granules, and small plastoglobules disappeared. SA-treated plants had significantly higher aboveground biomass than the untreated control exposed to Al stress. Photosynthetic index and gene expression analyses demonstrated that SA could alleviate adverse effects of Al toxicity by increasing light capture efficiency, promoting electron transport in the photosynthetic electron transport chain and thylakoid lumen deacidification, and promoting synthesis of aenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH). SA played protective roles in maintaining integrity and functions of photosystems in photosynthesis for plant tolerance to Al stress.
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Transcriptome analysis of two soybean cultivars identifies an aluminum respon-sive antioxidant enzyme GmCAT1. Biosci Biotechnol Biochem 2020; 84:1394-1400. [PMID: 32180505 DOI: 10.1080/09168451.2020.1740970] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/06/2020] [Indexed: 10/24/2022]
Abstract
This study investigated the antioxidant defense system involved in the tolerance of soybean (Glycine max) to aluminum (Al) stress. Physiological assays showed that the amount of superoxide free radicals (O2 -), hydrogen peroxide (H2O2), and malondialdehyde (MDA) were significantly lower in an Al-resistant soybean cultivar (cv. PI416937) than in an Al-sensitive soybean cultivar (cv. Huachun18). Comparative analysis of microarray data from both genotypes following Al-stress treatment revealed that the expression of a series of antioxidant enzymes genes was induced in the Al-resistant cultivar. The quantitative real time-PCR (qRT-PCR) assay showed that the transcript levels of genes encoding antioxidant enzymes, including GmCAT1, GmPOD1, GmGST1, GmAPX, GmGSH1, and GmSOD, were higher in the Al-resistant cultivar than in the Al-sensitive cultivar in Al-stress conditions. Furthermore, GmCAT1-overexpressing Arabidopsis plants had improved tolerance to Al-stress and lower O2 -, H2O2, and MDA contents than wild-type plants. Therefore, providing evidence that the antioxidant defense system is essential for Al tolerance in soybean. ABBREVIATIONS Al: aluminum; O2 -: superoxide free radicals; ROS: reactive oxygen species; H2O2: hydrogen peroxide; MDA: malondialdehyde; qRT-PCR: quantitative reverse transcription polymerase chain reaction; GO: gene ontology; WT: wild type; MS medium: Murashige and Skoog medium.
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Function of NHX-type transporters in improving rice tolerance to aluminum stress and soil acidity. PLANTA 2020; 251:71. [PMID: 32108903 DOI: 10.1007/s00425-020-03361-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/08/2020] [Indexed: 06/10/2023]
Abstract
In this study, we show that ectopic expression of either HtNHX1 or HtNHX2, from Helianthus tuberosus plant (located at vacuolar and endosome membranes, respectively), in rice plants could enhance its tolerance to aluminum (Al3+) stress and soil acidity. Plant sodium (potassium)/proton (Na+(K+)/H+ antiporters of the NHX family have been extensively characterized as they are related to the enhancement of salt tolerance. However, no previous study has reported NHX transporter functions in plant tolerance to Al3+ toxicity. In this study, we demonstrate their role as a component of the Al3+ stress tolerance mechanism. We show that the ectopic expression of either HtNHX1 or HtNHX2 , from Helianthus tuberosus plant, in rice (located at vacuole and endosome, respectively) could also enhance rice tolerance to Al3+ stress and soil acidity. Expression of either HtNHX1 or HtNHX2 reduced the inhibitory effect of Al3+ on the rice root elongation rate; both genes were reported to be equally effective in improvement of stress conditions. Expression of HtNHX1 enhanced Al3+-trigged-secretion of citrate acids, rhizosphere acidification, and also reduced K+ efflux from root tissues. In contrast, expression of HtNHX2 prevented Al3+-trigged-decrease of H+ influx into root tissues. Al3+-induced damage of the cell wall extensibility at the root tips was impaired by either HtNHX1 or HtNHX2. Co-expression of HtNHX1 and HtNHX2 further improved rice growth, particularly under the Al3+ stress conditions. The results demonstrate that HtNHX1 and HtNHX2 improved rice tolerance to Al3+ via different mechanisms by altering the K+ and H+ fluxes and the cell wall structure.
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14
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Influence of the plant growth promoting Rhizobium panacihumi on aluminum resistance in Panax ginseng. J Ginseng Res 2020; 45:442-449. [PMID: 34025137 PMCID: PMC8134844 DOI: 10.1016/j.jgr.2020.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 12/12/2019] [Accepted: 01/02/2020] [Indexed: 11/26/2022] Open
Abstract
Background Panax ginseng is an important crop in Asian countries given its pharmaceutical uses. It is usually harvested after 4–6 years of cultivation. However, various abiotic stresses have led to its quality reduction. One of the stress causes is high content of heavy metal in ginseng cultivation area. Plant growth–promoting rhizobacteria (PGPR) can play a role in healthy growth of plants. It has been considered as a new trend for supporting the growth of many crops in heavy metal occupied areas, such as Aluminum (Al). Methods In vitro screening of the plant growth promoting activities of five tested strains were detected. Surface-disinfected 2-year-old ginseng seedlings were dipping in Rhizobium panacihumi DCY116T suspensions for 15 min and cultured in pots for investigating Al resistance of P. ginseng. The harvesting was carried out 10 days after Al treatment. We then examined H2O2, proline, total soluble sugar, and total phenolic contents. We also checked the expressions of related genes (PgCAT, PgAPX, and PgP5CS) of reactive oxygen species scavenging response and pyrroline-5-carboxylate synthetase by reverse transcription polymerase chain reaction (RT-PCR) method. Results Among five tested strains isolated from ginseng-cultivated soil, R. panacihumi DCY116T was chosen as the potential PGPR candidate for further study. Ginseng seedlings treated with R. panacihumi DCY116T produced higher biomass, proline, total phenolic, total soluble sugar contents, and related gene expressions but decreased H2O2 level than nonbacterized Al-stressed seedlings. Conclusion R. panacihumi DCY116T can be used as potential PGPR and “plant strengthener” for future cultivation of ginseng or other crops/plants that are grown in regions with heavy metal exposure.
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Mapping QTLs of flag leaf morphological and physiological traits related to aluminum tolerance in wheat ( Triticum aestivum L.). PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2019; 25:975-990. [PMID: 31402821 PMCID: PMC6656840 DOI: 10.1007/s12298-019-00670-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/13/2019] [Accepted: 04/10/2019] [Indexed: 05/29/2023]
Abstract
Genetic improvement of aluminum (Al) tolerance is one of the cost-effective solutions to improve plant productivity in acidic soils around the world. This study was performed to progress our understanding of the genetic mechanisms of aluminum tolerance underlying wheat (Triticum aestivum L.) flag leaf morphological and physiological traits. A recombinant inbred line population derived from SeriM82 and Babax was used for mapping quantitative trait loci (QTL) in wheat for tolerance to Al toxicity through 477 DNA markers. Based on a single-locus analysis, 48 QTLs including 16 putative and 32 suggestive QTLs were identified for all studied traits. Individual QTL explained 4.57-11.29% of the phenotypic variance in different environments during both the crop seasons. These QTLs located unevenly throughout the wheat genome. Among them, 52.08%, 29.17%, and 18.75% were in the A, B, and D genomes, respectively. Based on two-locus analysis, 54 additive QTLs and 6 pairs of epistatic effects were detected, among which 29 additive and 5 pairs of epistatic QTLs showed significant QTL × environment interactions. The highest number of stable QTLs was identified on genome A. Determining a number of QTL clusters indicated tight linkage or pleiotropy in the inheritance of different traits. The stable and major QTLs controlling traits in this research can be applied for verification in different environments and genetic backgrounds and identifying superior allelic variations in wheat to increase the performance of selection of high yielding lines adapted to Al stress in breeding programs.
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Responses of duckweed (Lemna minor L.) to aluminum stress: Physiological and proteomics analyses. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 170:127-140. [PMID: 30529611 DOI: 10.1016/j.ecoenv.2018.11.113] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 06/09/2023]
Abstract
Aluminum (Al) is commonly considered an abiotic stress factor under acidic conditions. Duckweed (Lemna minor L.) has wide application in ecotoxicological research as a model organism and, in this study, its response to Al bioaccumulation was evaluated at morphological, physiological and proteomic levels. The Al accumulation in L. minor was accompanied by chlorosis and growth inhibition. Overproduction of superoxide and hydrogen peroxide, and decreased chlorophyll and protein contents, suggested that Al exposure induced oxidative stress. Inhibition of photosynthesis was evident in a significant decrease in maximum photosystem II quantum yield. There were 261 proteins, with significant changes in expression, successfully identified and quantified through isobaric tags for relative and absolute quantification (iTRAQ) analysis. Among the KEGG pathway enrichment proteins, those related to the citrate cycle and amino acid metabolism were predominantly up-regulated, whereas those associated with energy metabolism and glyoxylate and dicarboxylate metabolism were predominantly down-regulated. In addition, antioxidant enzyme related proteins played an important role in the response of L. minor to Al. The western blot analysis further validated the changes in photosynthetic related proteins. These results provide comprehensive insights into the physiological and molecular mechanisms of Al toxicity and tolerance in L. minor.
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The influence of Al 3+ on DNA methylation and sequence changes in the triticale (× Triticosecale Wittmack) genome. J Appl Genet 2018; 59:405-417. [PMID: 30159773 PMCID: PMC7902597 DOI: 10.1007/s13353-018-0459-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/24/2018] [Accepted: 08/07/2018] [Indexed: 01/28/2023]
Abstract
Abiotic stressors such as drought, salinity, and exposure to heavy metals can induce epigenetic changes in plants. In this study, liquid chromatography (RP-HPLC), methylation amplified fragment length polymorphisms (metAFLP), and methylation-sensitive amplification polymorphisms (MSAP) analysis was used to investigate the effects of aluminum (Al) stress on DNA methylation levels in the crop species triticale. RP-HPLC, but not metAFLP or MSAP, revealed significant differences in methylation between Al-tolerant (T) and non-tolerant (NT) triticale lines. The direction of methylation change was dependent on phenotype and organ. Al treatment increased the level of global DNA methylation in roots of T lines by approximately 0.6%, whereas demethylation of approximately 1.0% was observed in NT lines. DNA methylation in leaves was not affected by Al stress. The metAFLP and MSAP approaches identified DNA alterations induced by Al3+ treatment. The metAFLP technique revealed sequence changes in roots of all analyzed triticale lines and few mutations in leaves. MSAP showed that demethylation of CCGG sites reached approximately 3.97% and 3.75% for T and NT lines, respectively, and was more abundant than de novo methylation, which was observed only in two tolerant lines affected by Al stress. Three of the MSAP fragments showed similarity to genes involved in abiotic stress.
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Effect of short-term aluminum stress and mycorrhizal inoculation on nitric oxide metabolism in Medicago truncatula roots. JOURNAL OF PLANT PHYSIOLOGY 2018; 220:145-154. [PMID: 29179082 DOI: 10.1016/j.jplph.2017.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
Aluminum (Al) toxicity can induce oxidative and nitrosative stress, which limits growth and yield of crop plants. Nevertheless, plant tolerance to stress may be improved by symbiotic associations including arbuscular mycorrhiza (AM). Nitric oxide (NO) is a signaling molecule involved in physiological processes and plant responses to abiotic and biotic stresses. However, almost no information about the NO metabolism has been gathered about AM. In the present work, Medicago truncatula seedlings were inoculated with Rhizophagus irregularis, and 7-week-old plants were treated with 50μM AlCl3 for 3h. Cytochemical and molecular techniques were used to measure the components of the NO metabolism, including NO content and localization, expression of genes encoding NO-synthesis (MtNR1, MtNR2 and MtNIR1) and NO-scavenging (MtGSNOR1, MtGSNOR2, MtHB1 and MtHB2) enzymes and the profile of protein tyrosine nitration (NO2-Tyr) in Medicago roots. For the first time, NO and NO2-Tyr accumulation was connected with fungal structures (arbuscules, vesicles and intercellular hyphae). Expression analysis of genes encoding NO-synthesis enzymes indicated that AM symbiosis results in lower production of NO in Al-treated roots in comparison to non-mycorrhizal roots. Elevated levels of transcription of genes encoding NO-scavenging enzymes indicated more active NO scavenging in AMF-inoculated Al-treated roots compared to non-inoculated roots. These results were confirmed by less NO accumulation and lower protein nitration in Al-stressed mycorrhizal roots in comparison to non-mycorrhizal roots. This study provides a new insight in NO metabolism in response to arbuscular mycorrhiza under normal and metal stress conditions. Our results suggest that mycorrhizal fungi decrease NO and tyrosine nitrated proteins content in Al-treated Medicago roots, probably via active NO scavenging system.
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Genome-wide analysis of MATE transporters and molecular characterization of aluminum resistance in Populus. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5669-5683. [PMID: 29099944 PMCID: PMC5853298 DOI: 10.1093/jxb/erx370] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 09/28/2017] [Indexed: 05/21/2023]
Abstract
Ionic aluminum (Al) in acidic soils, comprising approximately 50% of arable land globally, is highly toxic to most plant species. Populus grow naturally in acidic soils and tolerate high concentrations of Al. Multidrug and toxic compound extrusion (MATE) family genes in plants are involved in responses to Al tolerance. To date, however, the functional roles of the MATE genes in Populus remain unclear. In the present study, 71 putative MATE transporters were predicted in the genome of Populus trichocarpa. The chromosome distribution, phylogenetic relationships, and expression level analysis revealed that four candidate MATE genes belonging to subgroup IIIc might contribute to high Al tolerance in poplar. Further, the expression levels of two subgroup IIIc members, PtrMATE1 and PtrMATE2, were induced by Al stress. Transient expression in onion epidermal cells showed that PtrMATE1 was localized to the plasma membrane. Overexpression of PtrMATE1 increased Al-induced secretion of citrate from the root apex of transgenic plants. Al-induced inhibition of root growths were alleviated in both PtrMATE1 overexpression lines in Populus and in Arabidopsis compared with wild-type plants. In addition, PtrMATE1 expression was induced at 12 h after exposure to Al stress whereas PtrMATE2 expression was induced at 24 h, indicating that these proteins coordinately function in response to Al stress in poplar. Taken together, these results provide important insights into the molecular mechanisms involved in Al tolerance in poplar.
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An RNA-Seq transcriptome analysis revealing novel insights into aluminum tolerance and accumulation in tea plant. PLANTA 2017; 246:91-103. [PMID: 28365842 DOI: 10.1007/s00425-017-2688-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/28/2017] [Indexed: 06/07/2023]
Abstract
The tea plant ( Camellia sinensis L. O. Kuntze) is a high aluminum (Al) tolerant and accumulator species. Candidate genes related to Al tolerance in tea plants were assembled based on de novo transcriptome analysis. The homologs implied some common and distinct Al-tolerant mechanism between tea plants and rice, Arabidopsis and buckwheat. In addition to high Al tolerance, the tea plant exhibits good performance exposure to a proper Al level, and accumulates high Al in the leaves without any toxicity symptom. Therefore, Al was considered as a hyperaccumulator and beneficial element for tea plants. However, the whole-genome molecular mechanisms accounting for Al-tolerance and accumulation remain unknown in tea plants. In this study, transcriptome analysis by RNA-Seq following a gradient Al-level exposure was assessed to further reveal candidate genes involved. Totally more than 468 million high-quality reads were generated and 213,699 unigenes were de novo assembled, among which 8922 unigenes were all annotated in the seven databases used. A large number of transporters, transcription factors, cytochrome P450, ubiquitin ligase, organic acid biosynthesis, heat shock proteins differentially expressed in response to high Al (P ≤ 0.05) were identified, which were most likely ideal candidates involved in the Al tolerance or accumulation. Furthermore, a few of the candidate Al-responsive genes related to Al sequestration, cell wall modification and organic acid excretion have been well elucidated as was already found in Arabidopsis, rice, and buckwheat. Thus, some consistent Al-tolerance mechanisms across the species are indicated. In conclusion, the transcriptome data provided useful insights of promising candidates for further characterizing the functions of genes involved in Al tolerance and accumulation in tea plants.
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Phytohormones enabled endophytic fungal symbiosis improve aluminum phytoextraction in tolerant Solanum lycopersicum: An examples of Penicillium janthinellum LK5 and comparison with exogenous GA3. JOURNAL OF HAZARDOUS MATERIALS 2015; 295:70-78. [PMID: 25885165 DOI: 10.1016/j.jhazmat.2015.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/30/2015] [Accepted: 04/03/2015] [Indexed: 06/04/2023]
Abstract
This work investigates the potentials of fungal-endophyte Penicillium janthinellum LK5 (PjLK5) and its inherent gibberellic acid (GA3) as reference to enhance aluminum (Al) induced toxicity in tolerant tomato (Solanum lycopersicum) plants. Initial screening showed significantly higher uptake of Al by PjLK5. Aluminum stress (100 μM) significantly retarted plant growth in control plants. Conversely PjLK5 and GA3 application significantly increased morphological attributes of Al-tolerant tomato plants with or without Al-stress. PjLK5 inoculation with and without Al-stress maintained the plant growth whilst extracting and translocating higher Al in shoot (∼ 1 92 mg/kg) and root (∼ 296 mg/kg). This was almost similar in GA3 treatments as well. In addition, PjLK5 inoculation extended protective effects to tomato plants by maintaining reduced cellular superoxide anions in Al stress. Al-induced oxidative stress was further reduced due to significantly higher activity of metal-responsive reduced glutathione. The functional membrane was less damaged in PjLK5 and GA3 treatments because the plants synthesized reduced levels of malondialdhyde, lenolenic and linoleic acids. Defense-related endogenous phytohormone salicylic acid was significantly up-regulated to counteract the adverse effects of Al-stress. In conclusion, the PjLK5 possess a similar bio-prospective potential as of GA3. Application of such biochemically active endophyte could increase metal phytoextraction whilst maintaining crop physiological homeostasis.
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Global transcriptome analysis of Al-induced genes in an Al-accumulating species, common buckwheat (Fagopyrum esculentum Moench). PLANT & CELL PHYSIOLOGY 2014; 55:2077-91. [PMID: 25273892 DOI: 10.1093/pcp/pcu135] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Buckwheat (Fagopyrum esculentum Moench) is a species with high aluminum (Al) tolerance and accumulation. Although the physiological mechanisms for external and internal detoxification of Al have been well studied, the molecular mechanisms responsible are poorly understood. Here, we conducted a genome-wide transcriptome analysis of Al-responsive genes in the roots and leaves using RNA sequencing (RNA-Seq) technology. RNA-Seq generated reads ranging from 56×10(6) to 93×10(6). A total of 148,734 transcript contigs with an average length of 1,014 bp were assembled, generating 84,516 unigenes. Among them, 31,730 and 23,853 unigenes were annotated, respectively, in the NCBI plant database and TAIR database for Arabidopsis. Of the annotated genes, 4,067 genes in the roots and 2,663 genes in the leaves were up-regulated (>2-fold) by Al exposure, while 2,456 genes in the roots and 2,426 genes in the leaves were down-regulated (<2-fold) A few STOP1/ART1 (SENSITIVE TO PROTON RHIZOTOXICITY1/AL RESISTANCE TRANSCRIPTION FACTOR1)-regulated gene homologs including FeSTAR1, FeALS3 (ALUMINUM SENSITIVE3), FeALS1 (ALUMINUM SENSITIVE1), FeMATE1 and FeMATE2 (MULTIDRUG AND TOXIC COMPOUND EXTRUSION1 and 2) were also up-regulated in buckwheat, indicating some common Al tolerance mechanism across the species, although most STOP1/ART1-regulated gene homologs were not changed. Most genes involved in citric and oxalic acid biosynthesis were not significantly altered. Some transporter genes were highly expressed in the roots and leaves and responded to Al stress, implicating their role in Al tolerance and accumulation. Overall, our data provide a platform for further characterizing the functions of genes involved in Al tolerance and accumulation in buckwheat.
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Root proteome of rice studied by iTRAQ provides integrated insight into aluminum stress tolerance mechanisms in plants. J Proteomics 2014; 98:189-205. [PMID: 24412201 DOI: 10.1016/j.jprot.2013.12.023] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 12/13/2013] [Accepted: 12/27/2013] [Indexed: 01/06/2023]
Abstract
One of the major limitations to crop growth on acid soils is the prevalence of soluble aluminum ions (Al(3+)). Rice (Oryza sativa L.) has been reported to be highly Al tolerant; however, large-scale proteomic data of rice in response to Al(3+) are still very scanty. Here, we used an iTRAQ-based quantitative proteomics approach for comparative analysis of the expression profiles of proteins in rice roots in response to Al(3+) at an early phase. A total of 700 distinct proteins (homologous proteins grouped together) with >95% confidence were identified. Among them, 106 proteins were differentially expressed upon Al(3+) toxicity in sensitive and tolerant cultivars. Bioinformatics analysis indicated that glycolysis/gluconeogenesis was the most significantly up-regulated biochemical process in response to excess Al(3+). The mRNA levels of eight proteins mapped in the glycolysis/gluconeogenesis were further analyzed by qPCR and the expression levels of all the eight genes were higher in tolerant cultivar than in sensitive cultivar, suggesting that these compounds may promote Al tolerance by modulating the production of available energy. Although the exact roles of these putative tolerance proteins remain to be examined, our data lead to a better understanding of the Al tolerance mechanisms in rice plants through the proteomics approach. BIOLOGICAL SIGNIFICANCE Aluminum (mainly Al(3+)) is one of the major limitations to the agricultural productivity on acid soils and causes heavy yield loss every year. Rice has been reported to be highly Al tolerant; however, the mechanisms of rice Al tolerance are still not fully understood. Here, a combined proteomics, bioinformatics and qPCR analysis revealed that Al(3+) invasion caused complex proteomic changes in rice roots involving energy, stress and defense, protein turnover, metabolism, signal transduction, transport and intracellular traffic, cell structure, cell growth/division, and transcription. Promotion of the glycolytic/gluconeogenetic pathway in roots appeared crucially important for Al tolerance. These results lead to a better understanding of the Al tolerance mechanisms in rice and help to improve plant performance on acid soils, eventually to increase the crop production.
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Localization of hydrogen peroxide accumulation and diamine oxidase activity in pea root nodules under aluminum stress. Micron 2014; 57:13-22. [PMID: 24246127 DOI: 10.1016/j.micron.2013.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 09/26/2013] [Accepted: 09/28/2013] [Indexed: 11/18/2022]
Abstract
Aluminum (Al) is one of the environmental stressors that induces formation of reactive oxygen species (ROS) in plants. Hydrogen peroxide (H2O2) and H2O2-generated apoplast diamine oxidase (DAO) activity were detected cytochemically via transmission electron microscopy (TEM), in pea (Pisum sativum L.) root nodules exposed to high (50 μM AlCl3, for 2 and 24h) Al stress. The nodules were shown to respond to Al stress by disturbances in infection thread (IT) growth, bacteria endocytosis, premature degeneration of bacteroidal tissue and generation of H2O2 in nodule apoplast. Large amounts of peroxide were found at the same sites as high DAO activity under Al stress, suggesting that DAO is a major source of Al-induced peroxide accumulation in the nodules. Peroxide distribution and DAO activity in the nodules of both control plants and Al-treated ones were typically found in the plant cell walls, intercellular spaces and infection threads. However, 2 h Al treatment increased DAO activity and peroxide accumulation in the nodule apoplast and bacteria within threads. A prolonged Al treatment (24 h) increased the H2O2 content and DAO activity in the nodule apoplast, especially in the thread walls, matrix and bacteria within infection threads. In addition to ITs, prematurely degenerated bacteroids, which occurred in response to Al, were associated with intense staining for H2O2 and DAO activity. These results suggest the involvement of DAO in the production of a large amount of H2O2 in the nodule apoplast under Al stress. The role of reactive oxygen species in pea-Rhizobium symbiosis under Al stress is discussed.
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