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Agustin Gonzalezfontes - One of the best experts on this subject based on the ideXlab platform.
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root responses to Boron Deficiency mediated by ethylene
2016Co-Authors: Agustin Gonzalezfontes, Jesus Rexach, Maria Begona Herrerarodriguez, Esperanza M Martinrejano, Maria Teresa Navarrogochicoa, Juan J CamachocristobalAbstract:Low Boron (B) supply alters the architecture of the root system in Arabidopsis thaliana seedlings, leading to a reduction in the primary root growth and an increase in the length and number of root hairs. At short-term (hours), B Deficiency causes a decrease in the cell elongation of the primary root, resulting in a lower growth. Experimental approaches using ethylene insensitive arabidopsis mutants, inhibitors of ethylene response, and GUS reporter lines suggest that ethylene is involved in these responses of the primary root to B Deficiency. Furthermore, it has been shown that auxin participates in the inhibition of cell elongation under short-term B deprivation. These results support that an interaction between ethylene and auxin plays an important role in controlling the primary root elongation, in which a number of genes related to the synthesis, transport, and signaling of both phytohormones could modulate this effect. Evidence for a root cross-talk among both hormones and other possible intermediates (abscisic acid, calcium sensors, and reactive oxygen species) in response to B Deficiency is provided and discussed.
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Boron Deficiency inhibits root cell elongation via an ethylene auxin ros dependent pathway in arabidopsis seedlings
2015Co-Authors: Juan J Camachocristobal, Jesus Rexach, Begona M Herrerarodriguez, Teresa M Navarrogochicoa, Esperanza M Martinrejano, Agustin GonzalezfontesAbstract:One of the earliest symptoms of Boron (B) Deficiency is the inhibition of root elongation which can reasonably be attributed to the damaging effects of B deprivation on cell wall integrity. It is shown here that exposure of wild-type Arabidopsis thaliana seedlings to B Deficiency for 4h led to a drastic inhibition of root cell length in the transition between the elongation and differentiation zones. To investigate the possible mediation of ethylene, auxin, and reactive oxygen species (ROS) in the effect of B Deficiency on root cell elongation, B Deficiency was applied together with aminoethoxyvinylglycine (AVG, a chemical inhibitor of ethylene biosynthesis), silver ions (Ag(+), an antagonist of ethylene perception), α-(phenylethyl-2-oxo)-indoleacetic acid (PEO-IAA, a synthetic antagonist of TIR1 receptor function), and diphenylene iodonium (DPI, an inhibitor of ROS production). Interestingly, all these chemicals partially or fully restored cell elongation in B-deficient roots. To further explore the possible role of ethylene and auxin in the inhibition of root cell elongation under B Deficiency, a genetic approach was performed by using Arabidopsis mutants defective in the ethylene (ein2-1) or auxin (eir1-4 and aux1-22) response. Root cell elongation in these mutants was less sensitive to B-deficient treatment than that in wild-type plants. Altogether, these results demonstrated that a signalling pathway involving ethylene, auxin, and ROS participates in the reduction of root cell elongation when Arabidopsis seedlings are subjected to B Deficiency. A similar signalling process has been described to reduce root elongation rapidly under various types of cell wall stress which supports the idea that this signalling pathway is triggered by the impaired cell wall integrity caused by B Deficiency.
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Boron Deficiency and transcript level changes
2011Co-Authors: Juan J Camachocristobal, Jesus Rexach, Begona M Herrerarodriguez, Teresa M Navarrogochicoa, Agustin GonzalezfontesAbstract:Boron (B) is an essential element for plant growth whose Deficiency causes an alteration in the expression of a wide range of genes involved in several physiological processes. However, our understanding of the signal transduction pathways that trigger the B-Deficiency responses in plants is still poor. The aims of this review are (i) to summarize the genes whose transcript levels are affected by B Deficiency and (ii) to provide an update on recent findings that could help to understand how the signal(s) triggered by B Deficiency is transferred to the nucleus to modulate gene expression. In this contribution we review the effects of B Deficiency on the transcript level of genes related to B uptake and translocation, maintenance of cell wall and membrane function, nitrogen assimilation and stress response. In addition, we discuss the possible mediation of calcium, arabinogalactan-proteins and other cis-diol containing compounds in the signaling mechanisms that transfer the signal of B Deficiency to nuclei. Finally, we conclude that the advance in the knowledge of the molecular basis of B Deficiency response in plants will allow improving the tolerance of crops to B Deficiency stress.
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Boron Deficiency decreases plasmalemma h atpase expression and nitrate uptake and promotes ammonium assimilation into asparagine in tobacco roots
2007Co-Authors: Juan J Camachocristobal, Agustin GonzalezfontesAbstract:The effects of short-term Boron Deficiency on several aspects (growth, biomass allocation, metabolite concentrations, gene expression, enzyme activities) related with nitrate assimilation were studied in tobacco (Nicotiana tabacum L.) plants in order to know the early changes caused by this mineral Deficiency. For this purpose, plants were grown hydroponically in a nutrient solution supplemented with 10 μM Boron and then transferred to a Boron-free medium for 1–5 days. Nitrate concentration decreased in both leaves and roots under Boron Deficiency, which was not observed in control plants. This correlated with the lower net nitrate uptake rate found in Boron-deficient plants when compared to Boron-sufficient ones. Results suggest that Boron Deficiency decreases net nitrate uptake by declining the activity of nitrate transporters rather than affecting their transcript levels. This is supported by a drop in the levels of root PMA2 transcript during the Boron deficient treatment, which could lead to a decrease in the plasma membrane H+-ATPase activity necessary to get protons out of cell for the cotransport with nitrate inwards. In addition, Boron Deficiency led to an increase in root Asn content and a decline in glutamine synthetase activity when compared to control plants, which suggest that this mineral Deficiency may promote ammonium assimilation via asparagine synthetase in tobacco roots.
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Boron Deficiency increases putrescine levels in tobacco plants
2005Co-Authors: Juan J Camachocristobal, J M Maldonado, Agustin GonzalezfontesAbstract:Polyamine concentrations were determined in leaves and roots of tobacco plants (Nicotiana tabacum L.) subjected to a short-term Boron Deficiency. A decrease in the growth of shoots and, especially, roots was found under this mineral Deficiency. Boron Deficiency did not lead to a significant decrease in leaf or root ion concentrations when compared to control treatment; however, as expected, leaf Boron concentration was lower in Boron-deficient plants in comparison to the control. In leaves, the levels of free putrescine and spermidine were similar in both treatments. In roots, a short-term Boron Deficiency caused an increase in free putrescine. Moreover, Boron-deficient plants had higher conjugated polyamine concentration than Boron-sufficient plants, which was especially evident for conjugated putrescine in leaves. A possible link between Boron and polyamine levels is proposed and discussed.
Lisong Chen - One of the best experts on this subject based on the ideXlab platform.
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proteomic profile of citrus grandis roots under long term Boron Deficiency revealed by itraq
2016Co-Authors: Lintong Yang, Yuan Zhang, Peng Guo, Lisong ChenAbstract:Eighty-six differentially abundant proteins were identified in Citrus grandis roots in response to Boron-Deficiency using the iTRAQ technique and possible mechanism underlying Boron-Deficiency tolerance of citrus plants was identified. Boron (B) is an essential element for plant growth and development and adequate B supply is an important determinant of good quality and high yield of crops. B-Deficiency is a worldwide problem in agricultural production including citrus. However, little is known about the molecular mechanism of plant tolerance to B-Deficiency. Using the iTRAQ technique, 86 differentially abundant proteins were identified from B-deficient Citrus grandis roots. The adaptive strategy of C. grandis roots under B-Deficiency was summarized as follows: (1) enhancement of alternative splicing of mRNA and DNA methylation; (2) up-regulation of post-translation modification (PTM) and turnover of proteins; (3) reinforcement of cellular transport; (4) enhancement of antioxidant system and signal transduction. In general, these results increase our understanding of molecular mechanisms underlining the resistance of citrus plant under B-Deficiency. Further studies should focus on how do roots perceive B Deficiency in the rhizosphere and which pathway or proteins react to this adverse condition in the first place and then stimulates the downstream responses in Citrus plants.
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Boron Deficiency responsive micrornas and their targets in citrus sinensis leaves
2015Co-Authors: Lintong Yang, Peng Guo, Lisong ChenAbstract:MicroRNAs play important roles in the adaptive responses of plants to nutrient deficiencies. Most research, however, has focused on nitrogen (N), phosphorus (P), sulfur (S), copper (Cu) and iron (Fe) deficiencies, limited data are available on the differential expression of miRNAs and their target genes in response to deficiencies of other nutrient elements. In this study, we identified the known and novel miRNAs as well as the Boron (B)-Deficiency-responsive miRNAs from citrus leaves in order to obtain the potential miRNAs related to the tolerance of citrus to B-Deficiency. Seedlings of ‘Xuegan’ [Citrus sinensis (L.) Osbeck] were supplied every other day with B-deficient (0 μM H3BO3) or -sufficient (10 μM H3BO3) nutrient solution for 15 weeks. Thereafter, we sequenced two small RNA libraries from B-deficient and -sufficient (control) citrus leaves, respectively, using Illumina sequencing. Ninety one (83 known and 8 novel) up- and 81 (75 known and 6 novel) down-regulated miRNAs were isolated from B-deficient leaves. The great alteration of miRNA expression might contribute to the tolerance of citrus to B-Deficiency. The adaptive responses of miRNAs to B-Deficiency might related to several aspects: (a) attenuation of plant growth and development by repressing auxin signaling due to decreased TIR1 level and ARF-mediated gene expression by altering the expression of miR393, miR160 and miR3946; (b) maintaining leaf phenotype and enhancing the stress tolerance by up-regulating NACs targeted by miR159, miR782, miR3946 and miR7539; (c) activation of the stress responses and antioxidant system through down-regulating the expression of miR164, miR6260, miR5929, miR6214, miR3946 and miR3446; (d) decreasing the expression of major facilitator superfamily protein genes targeted by miR5037, thus lowering B export from plants. Also, B-Deficiency-induced down-regulation of miR408 might play a role in plant tolerance to B-Deficiency by regulating Cu homeostasis and enhancing superoxide dismutase activity. Our study reveals some novel responses of citrus to B-Deficiency, which increase our understanding of the adaptive mechanisms of citrus to B-Deficiency at the miRNA (post-transcriptional) level.
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identification of Boron Deficiency responsive micrornas in citrus sinensis roots by illumina sequencing
2014Co-Authors: Lintong Yang, Yanbin Chen, Zengrong Huang, Lisong ChenAbstract:Boron (B)-Deficiency is a widespread problem in many crops, including Citrus. MicroRNAs (miRNAs) play important roles in nutrient deficiencies. However, little is known on B-Deficiency-responsive miRNAs in plants. In this study, we first identified miRNAs and their expression pattern in B-deficient Citrus sinensis roots by Illumina sequencing in order to identify miRNAs that might be involved in the tolerance of plants to B-Deficiency. We isolated 52 (40 known and 12 novel) up-regulated and 82 (72 known and 10 novel) down-regulated miRNAs from B-deficient roots, demonstrating remarkable metabolic flexibility of roots, which might contribute to the tolerance of plants to B-Deficiency. A model for the possible roles of miRNAs in the tolerance of roots to B-Deficiency was proposed. miRNAs might regulate the adaptations of roots to B-Deficiency through following several aspects: (a) inactivating reactive oxygen species (ROS) signaling and scavenging through up-regulating miR474 and down-regulating miR782 and miR843; (b) increasing lateral root number by lowering miR5023 expression and maintaining a certain phenotype favorable for B-Deficiency-tolerance by increasing miR394 expression; (c) enhancing cell transport by decreasing the transcripts of miR830, miR5266 and miR3465; (d) improving osmoprotection (miR474) and regulating other metabolic reactions (miR5023 and miR821). Other miRNAs such as miR472 and miR2118 in roots increased in response to B-Deficiency, thus decreasing the expression of their target genes, which are involved in disease resistance, and hence, the disease resistance of roots. Our work demonstrates the possible roles of miRNAs and related mechanisms in the response of plant roots to B-Deficiency.
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itraq protein profile analysis of citrus sinensis roots in response to long term Boron Deficiency
2013Co-Authors: Lintong Yang, Peng Guo, Wen Sang, Hui Feng, Hongxing Zhang, Lisong ChenAbstract:Abstract Seedlings of Citrus sinensis were fertilized with Boron (B)-deficient (0 μM H 3 BO 3 ) or -sufficient (10 μM H 3 BO 3 ) nutrient solution for 15 weeks. Thereafter, iTRAQ analysis was employed to compare the abundances of proteins from B-deficient and -sufficient roots. In B-deficient roots, 164 up-regulated and 225 down-regulated proteins were identified. These proteins were grouped into the following functional categories: protein metabolism, nucleic acid metabolism, stress responses, carbohydrate and energy metabolism, cell transport, cell wall and cytoskeleton metabolism, biological regulation and signal transduction, and lipid metabolism. The adaptive responses of roots to B-Deficiency might include following several aspects: ( a ) decreasing root respiration; ( b ) improving the total ability to scavenge reactive oxygen species (ROS); and ( c ) enhancing cell transport. The differentially expressed proteins identified by iTRAQ are much larger than those detected using 2D gel electrophoresis, and many novel B-Deficiency-responsive proteins involved in cell transport, biological regulation and signal transduction, stress responses and other metabolic processes were identified in this work. Our results indicate remarkable metabolic flexibility of citrus roots, which may contribute to the survival of B-deficient plants. This represents the most comprehensive analysis of protein profiles in response to B-Deficiency. Biological significance In this study, we identified many new proteins involved in cell transport, biological regulation and signal transduction, stress responses and other metabolic processes that were not previously known to be associated with root B-Deficiency responses. Therefore, our manuscript represents the most comprehensive analysis of protein profiles in response to B-Deficiency and provides new information about the plant response to B-Deficiency. This article is part of a Special Issue entitled: Translational Plant Proteomics.
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Boron Deficiency decreases growth and photosynthesis and increases starch and hexoses in leaves of citrus seedlings
2008Co-Authors: Shuang Han, Lintong Yang, Lisong Chen, Huanxin Jiang, Brandon R Smith, Chengyu XieAbstract:Seedlings of sweet orange (Citrus sinensis) were fertilized for 14 weeks with Boron (B)-free or B-sufficient (2.5 or 10 microM H(3)BO(3)) nutrient solution every other day. Boron Deficiency resulted in an overall inhibition of plant growth, with a reduction in root, stem and leaf dry weight (DW). Boron-starved leaves showed decreased CO(2) assimilation and stomatal conductance, but increased intercellular CO(2) concentrations. Activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), NADP-glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH) and stromal fructose-1,6-bisphosphatase (FBPase) were lower in B-deficient leaves than in controls. Contents of glucose, fructose and starch were increased in B-deficient leaves while sucrose was decreased. Boron-deficient leaves displayed higher or similar superoxide dismutase (SOD), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR) and glutathione reductase (GR) activities, while dehydroascorbate reductase (DHAR) and catalase (CAT) activities were lower. Expressed on a leaf area or protein basis, B-deficient leaves showed a higher ascorbate (AsA) concentration, but a similar AsA concentration on a DW basis. For reduced glutathione (GSH), we found a similar GSH concentration on a leaf area or protein basis and an even lower content on a DW basis. Superoxide anion (O(2)(-)) generation, malondialdehyde (MDA) concentration and electrolyte leakage were higher in B-deficient than in control leaves. In conclusion, CO(2) assimilation may be feedback-regulated by the excessive accumulation of starch and hexoses in B-deficient leaves via direct interference with chloroplast function and/or indirect repression of photosynthetic enzymes. Although B-deficient leaves remain high in activity of antioxidant enzymes, their antioxidant system as a whole does not provide sufficient protection from oxidative damage.
Toru Fujiwara - One of the best experts on this subject based on the ideXlab platform.
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improved tolerance to Boron Deficiency by enhanced expression of the Boron transporter bor2
2014Co-Authors: Shigeki Takada, Toru Fujiwara, Kyoko Miwa, Hiroyuki Omori, Satoshi Naito, Junpei TakanoAbstract:AbstractBoron (B) cross-links the pectin polysaccharide rhamnogalacturonan II (RG-II) and thus is important for cell wall structure in plants. B Deficiency is an agricultural problem that causes significant losses of crop productivity worldwide. To address this, B Deficiency-tolerant plants have been generated using B transporters. With the goal of further improving plant tolerance to low-B conditions, we generated transgenic Arabidopsis thaliana (L.) Heynh. with enhanced expression of BOR2, a B transporter that promotes cross-linking of RG-II and root elongation under low B supply. We generated a DNA construct containing the cauliflower mosaic virus 35S RNA promoter, a native promoter of BOR2, a BOR2 gene and green fluorescent protein (GFP) (Pro35S-BOR2:BOR2-GFP), and obtained three independent transgenic lines with relatively high levels of BOR2-GFP expression. In the transgenic lines, BOR2-GFP was expressed mainly in the lateral root caps in the meristem zone and in the epidermal cells in the elongatio...
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generation of Boron Deficiency tolerant tomato by overexpressing an arabidopsis thaliana borate transporter atbor1
2014Co-Authors: Shimpei Uraguchi, Kyoko Miwa, Yuichi Kato, Hideki Hanaoka, Toru FujiwaraAbstract:Nutrient Deficiency in soil poses a widespread agricultural problem. Boron (B) is an essential micronutrient in plants, and its Deficiency causes defects in both vegetative and reproductive growth in various crops in the field. In Arabidopsis thaliana, increased expression of a major borate transporter gene AtBOR1 or boric acid channel gene AtNIP5;1 improves plant growth under B-deficient conditions. In this study, we examined whether high expression of a borate transporter gene increases B accumulation in shoots and improves the growth of tomato plant, a model of fruit-bearing crops, under B-deficient conditions. We established three independent transgenic tomato plants lines expressing AtBOR1 using Agrobacterium-mediated transformation of tomato (Solanum lycopersicum L. cv. Micro-Tom). Reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed that two lines (Line 1 and Line 2) more strongly expressed AtBOR1 than Line 3. Wild-type plants and the transgenic plants were grown hydroponically under B-sufficient and B-deficient conditions. Wild-type and Line 3 (weakly expressing transgenic line) showed a defect in shoot growth under B-deficient conditions, especially in the development of new leaves. However, seedlings of Line 1 and Line 2, the transgenic lines showing strong AtBOR1 expression, did not show the B-Deficiency phenotype in newly developing leaves. In agreement with this phenotype, shoot biomass under low-B conditions was higher in the strongly expressing AtBOR1 line. B concentrations in leaves or fruits were also higher in Line 2 and Line 1. The present study demonstrates that strong expression of AtBOR1 improved growth in tomato under B-deficient conditions.
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possible involvement of ploidy in tolerance to Boron Deficiency in arabidopsis thaliana
2010Co-Authors: Ichiro Kasajima, Takeshi Yoshizumi, Takanari Ichikawa, Minami Matsui, Toru FujiwaraAbstract:Boron is an essential nutrient for plant growth and reproduction. To identify a novel genetic mechanism which contributes to plant tolerance to nutrient Deficiency, we screened Arabidopsis thaliana mutants for those tolerant to nutrient deficiencies. One of the isolated lines was tolerant to Boron Deficiency. This line was designated as LoBT1. From morphological characteristics and ploidy analysis, LoBT1 was found to be tetraploid, although the original screening population was diploid. Because LoBT1 is most likely to be created by the spontaneous duplication of the same diploid genome, LoBT1 is ‘autotetraploid’. Independently isolated autotetraploid A. thaliana lines which were obtained from the ABRC stock center were also tolerant to Boron Deficiency, showing that autotetraploidization generally improves tolerance to Boron Deficiency. Our results represent the first demonstration that autopolyploidization can improve tolerance to environmental stress. Because the clear tolerance was observed under a model system, our observation offers considerable resources to analyze autotetraploid tolerance to environmental stress in more details.
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wrky6 is involved in the response to Boron Deficiency in arabidopsis thaliana
2010Co-Authors: Ichiro Kasajima, Yoko Ide, Masami Yokota Hirai, Toru FujiwaraAbstract:Boron (B) is one of the essential nutrients for plant growth and reproduction. Transcriptome analyses have identified genes regulated by B Deficiency, but their function mostly remains elusive. To identify the functions of B Deficiency-inducible genes, T-DNA insertion mutants of 10 B Deficiency-induced genes were obtained, and their growth properties in response to B conditions were examined. Among the lines examined, mutants of the transcription factor WRKY6 showed growth defect compared with the wild-type under B Deficiency, but not under normal conditions. This growth defect was commonly observed among three independently isolated wrky6 mutants. There was no significant difference in B concentration between wrky6-3 and the wild-type. Promoter activity of WRKY6 was induced around the root tip under B Deficiency. These results established that WRKY6 is a low-B-induced transcription factor gene that is essential for normal root growth under low-B conditions. Transcriptome analysis around the root tip identified WRKY6-regulated genes under B Deficiency. Our findings represent the first identification of a transcription factor involved in the response to B Deficiency.
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highly Boron Deficiency tolerant plants generated by enhanced expression of nip5 1 a boric acid channel
2009Co-Authors: Yuichi Kato, Kyoko Miwa, Junpei Takano, Motoko Wada, Toru FujiwaraAbstract:: Boron (B) is an essential element for plants, and B Deficiency is a worldwide agricultural problem. In B-deficient areas, B is often supplied as fertilizer, but excess B can be toxic to both plants and animals. Generation of B Deficiency-tolerant plants could reduce B fertilizer use. Improved fertility under B-limiting conditions in Arabidopsis thaliana by overexpression of BOR1, a B transporter, has been reported, but the root growth was not improved by the BOR1 overexpression. In this study, we report that enhanced expression of NIP5;1, a boric acid channel for efficient B uptake, resulted in improved root elongation under B-limiting conditions in A. thaliana. An NIP5;1 activation tag line, which has a T-DNA insertion with enhancer sequences near the NIP5;1 gene, showed improved root elongation under B limitation. We generated a construct which mimics the tag line: the cauliflower mosaic virus 35S RNA promoter was inserted at 1,357 bp upstream of the NIP5;1 transcription initiation site. Introduction of this construct into the nip5;1-1 mutant and the BOR1 overexpresser resulted in enhanced expression of NIP5;1 and improved root elongation under low B supply. Furthermore, one of the transgenic lines exhibited improved fertility and short-term B uptake. Our results demonstrate successful improvement of B Deficiency tolerance and the potential of enhancing expression of a mineral nutrient channel gene to improve growth under nutrient-limiting conditions.
Juan J Camachocristobal - One of the best experts on this subject based on the ideXlab platform.
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root responses to Boron Deficiency mediated by ethylene
2016Co-Authors: Agustin Gonzalezfontes, Jesus Rexach, Maria Begona Herrerarodriguez, Esperanza M Martinrejano, Maria Teresa Navarrogochicoa, Juan J CamachocristobalAbstract:Low Boron (B) supply alters the architecture of the root system in Arabidopsis thaliana seedlings, leading to a reduction in the primary root growth and an increase in the length and number of root hairs. At short-term (hours), B Deficiency causes a decrease in the cell elongation of the primary root, resulting in a lower growth. Experimental approaches using ethylene insensitive arabidopsis mutants, inhibitors of ethylene response, and GUS reporter lines suggest that ethylene is involved in these responses of the primary root to B Deficiency. Furthermore, it has been shown that auxin participates in the inhibition of cell elongation under short-term B deprivation. These results support that an interaction between ethylene and auxin plays an important role in controlling the primary root elongation, in which a number of genes related to the synthesis, transport, and signaling of both phytohormones could modulate this effect. Evidence for a root cross-talk among both hormones and other possible intermediates (abscisic acid, calcium sensors, and reactive oxygen species) in response to B Deficiency is provided and discussed.
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Boron Deficiency inhibits root cell elongation via an ethylene auxin ros dependent pathway in arabidopsis seedlings
2015Co-Authors: Juan J Camachocristobal, Jesus Rexach, Begona M Herrerarodriguez, Teresa M Navarrogochicoa, Esperanza M Martinrejano, Agustin GonzalezfontesAbstract:One of the earliest symptoms of Boron (B) Deficiency is the inhibition of root elongation which can reasonably be attributed to the damaging effects of B deprivation on cell wall integrity. It is shown here that exposure of wild-type Arabidopsis thaliana seedlings to B Deficiency for 4h led to a drastic inhibition of root cell length in the transition between the elongation and differentiation zones. To investigate the possible mediation of ethylene, auxin, and reactive oxygen species (ROS) in the effect of B Deficiency on root cell elongation, B Deficiency was applied together with aminoethoxyvinylglycine (AVG, a chemical inhibitor of ethylene biosynthesis), silver ions (Ag(+), an antagonist of ethylene perception), α-(phenylethyl-2-oxo)-indoleacetic acid (PEO-IAA, a synthetic antagonist of TIR1 receptor function), and diphenylene iodonium (DPI, an inhibitor of ROS production). Interestingly, all these chemicals partially or fully restored cell elongation in B-deficient roots. To further explore the possible role of ethylene and auxin in the inhibition of root cell elongation under B Deficiency, a genetic approach was performed by using Arabidopsis mutants defective in the ethylene (ein2-1) or auxin (eir1-4 and aux1-22) response. Root cell elongation in these mutants was less sensitive to B-deficient treatment than that in wild-type plants. Altogether, these results demonstrated that a signalling pathway involving ethylene, auxin, and ROS participates in the reduction of root cell elongation when Arabidopsis seedlings are subjected to B Deficiency. A similar signalling process has been described to reduce root elongation rapidly under various types of cell wall stress which supports the idea that this signalling pathway is triggered by the impaired cell wall integrity caused by B Deficiency.
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Boron Deficiency and transcript level changes
2011Co-Authors: Juan J Camachocristobal, Jesus Rexach, Begona M Herrerarodriguez, Teresa M Navarrogochicoa, Agustin GonzalezfontesAbstract:Boron (B) is an essential element for plant growth whose Deficiency causes an alteration in the expression of a wide range of genes involved in several physiological processes. However, our understanding of the signal transduction pathways that trigger the B-Deficiency responses in plants is still poor. The aims of this review are (i) to summarize the genes whose transcript levels are affected by B Deficiency and (ii) to provide an update on recent findings that could help to understand how the signal(s) triggered by B Deficiency is transferred to the nucleus to modulate gene expression. In this contribution we review the effects of B Deficiency on the transcript level of genes related to B uptake and translocation, maintenance of cell wall and membrane function, nitrogen assimilation and stress response. In addition, we discuss the possible mediation of calcium, arabinogalactan-proteins and other cis-diol containing compounds in the signaling mechanisms that transfer the signal of B Deficiency to nuclei. Finally, we conclude that the advance in the knowledge of the molecular basis of B Deficiency response in plants will allow improving the tolerance of crops to B Deficiency stress.
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Boron Deficiency decreases plasmalemma h atpase expression and nitrate uptake and promotes ammonium assimilation into asparagine in tobacco roots
2007Co-Authors: Juan J Camachocristobal, Agustin GonzalezfontesAbstract:The effects of short-term Boron Deficiency on several aspects (growth, biomass allocation, metabolite concentrations, gene expression, enzyme activities) related with nitrate assimilation were studied in tobacco (Nicotiana tabacum L.) plants in order to know the early changes caused by this mineral Deficiency. For this purpose, plants were grown hydroponically in a nutrient solution supplemented with 10 μM Boron and then transferred to a Boron-free medium for 1–5 days. Nitrate concentration decreased in both leaves and roots under Boron Deficiency, which was not observed in control plants. This correlated with the lower net nitrate uptake rate found in Boron-deficient plants when compared to Boron-sufficient ones. Results suggest that Boron Deficiency decreases net nitrate uptake by declining the activity of nitrate transporters rather than affecting their transcript levels. This is supported by a drop in the levels of root PMA2 transcript during the Boron deficient treatment, which could lead to a decrease in the plasma membrane H+-ATPase activity necessary to get protons out of cell for the cotransport with nitrate inwards. In addition, Boron Deficiency led to an increase in root Asn content and a decline in glutamine synthetase activity when compared to control plants, which suggest that this mineral Deficiency may promote ammonium assimilation via asparagine synthetase in tobacco roots.
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Boron Deficiency increases putrescine levels in tobacco plants
2005Co-Authors: Juan J Camachocristobal, J M Maldonado, Agustin GonzalezfontesAbstract:Polyamine concentrations were determined in leaves and roots of tobacco plants (Nicotiana tabacum L.) subjected to a short-term Boron Deficiency. A decrease in the growth of shoots and, especially, roots was found under this mineral Deficiency. Boron Deficiency did not lead to a significant decrease in leaf or root ion concentrations when compared to control treatment; however, as expected, leaf Boron concentration was lower in Boron-deficient plants in comparison to the control. In leaves, the levels of free putrescine and spermidine were similar in both treatments. In roots, a short-term Boron Deficiency caused an increase in free putrescine. Moreover, Boron-deficient plants had higher conjugated polyamine concentration than Boron-sufficient plants, which was especially evident for conjugated putrescine in leaves. A possible link between Boron and polyamine levels is proposed and discussed.
Lei Shi - One of the best experts on this subject based on the ideXlab platform.
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Boron Deficiency induced root growth inhibition is mediated by brassinosteroid signalling regulation in arabidopsis
2021Co-Authors: Cheng Zhang, Sheliang Wang, Guangda Ding, Liuyang Chu, Chuang Wang, Ningmei Yang, Hongmei Cai, Lei ShiAbstract:Brassinosteroids (BRs) are pivotal phytohormones involved in dominating root development. Boron (B) is an essential micronutrient for plants, and root growth is rapidly inhibited under B-Deficiency conditions. However, the mechanisms underlying this inhibition are still unclear. Here, we identified BR-related processes underlying B Deficiency at the physiological, genetic, molecular/cell biological and transcriptomic levels and found strong evidence that B Deficiency can affect BR biosynthesis and signalling, thereby altering root growth. RNA sequencing analysis revealed strong co-regulation between BR-regulated genes and B Deficiency-responsive genes. We found that the BR receptor mutants bri1-119 and bri1-301 were more insensitive to decreased B supply, and the gain-of function mutants bes1-D and pBZR1-bzr1-D lines exhibited insensitivity to low-B stress. Under B-Deficiency conditions, exogenous 24-epibrassinolide (eBL) rescued the inhibition of root growth, and application of the BR biosynthesis inhibitor BRZ exacerbated this inhibitory effect. The nuclear-localized signal of BES1 was reduced under low-B conditions compared with B-sufficiency conditions. We further found that B Deficiency hindered the accumulation of brassinolide (BL) to downregulate BR signalling and modulate root elongation, which may occur through a reduction in BR6ox1 and BR6ox2 mRNA levels. Taken together, our results reveal a role of BR signalling in root elongation under B Deficiency.
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Boron Deficiency induced root growth inhibition is mediated by br signal regulation in arabidopsis
2019Co-Authors: Cheng Zhang, Guangda Ding, Shaobin Wang, Liuyang Chu, Chuang Wang, Ningmei Yang, Hongmei Cai, Lei ShiAbstract:Brassinosteroid (BR) is a pivotal phytohormone involved in regulating root development. Boron (B) is an essential micronutrient for plant growth and development, and root growth of plants is rapidly inhibited under B Deficiency condition, but the mechanisms are still elusive. Here, we demonstrate that BR plays crucial roles in these processes. We identify BR-related processes underlying B Deficiency at the physiological, genetic, molecular/cell biological and transcriptome levels, and provide strong evidences that B Deficiency can affect BR signalling, thereby altering root growth. RNA-sequencing analysis reveals a high co-regulation between BR-regulated genes and B Deficiency-responsive genes. We found that low B negatively regulates BR signalling to control BR signalling-dependent root elongation, bes1-D exhibits insensitivity to low B stress, and bri1-301 mutants fails to respond to B depletion. Exogenous eBL application can rescue the inhibition of root growth under B Deficiency condition, and application of BR biosynthesis inhibitor BRZ aggravates root growth inhibition of wild-type under B Deficiency condition. B Deficiency reduces the nuclear signal of BES1. We further found that B Deficiency reduces the accumulation of brassinolide (BL) by reducing BR6ox1 and BR6ox2 mRNA level to down-regulate BR signalling and modulate root elongation. Altogether, our results uncover a role of BR signalling in root elongation under B Deficiency. One-sentence summaryB Deficiency reduces the accumulation of brassinolide by reducing BR6ox1 and BR6ox2 mRNA level to down-regulate BR signalling and modulate root elongation.
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Boron Deficiency induced root growth inhibition is mediated by brassinosteroid signalling regulation in arabidopsis
2019Co-Authors: Cheng Zhang, Sheliang Wang, Guangda Ding, Liuyang Chu, Chuang Wang, Ningmei Yang, Hongmei Cai, Lei ShiAbstract:ABSTRACT Brassinosteroid (BR) is a pivotal phytohormone involved in regulating root development. Boron (B) is an essential micronutrient for plant growth and development, and root growth of plants is rapidly inhibited under B Deficiency condition, but the mechanisms are still elusive. Here, we demonstrate that BR plays crucial roles in these processes. We identify BR-related processes underlying B Deficiency at the physiological, genetic, molecular/cell biological and transcriptome levels, and provide strong evidences that B Deficiency can affect BR signalling, thereby altering root growth. RNA-sequencing analysis reveals a high co-regulation between BR-regulated genes and B Deficiency-responsive genes. We found that low B negatively regulates BR signalling to control BR signalling-dependent root elongation, bes1-D exhibits insensitivity to low B stress, and bri1-301 mutants fails to respond to B depletion. Exogenous eBL application can rescue the inhibition of root growth under B Deficiency condition, and application of BR biosynthesis inhibitor BRZ aggravates root growth inhibition of wild-type under B Deficiency condition. B Deficiency reduces the nuclear signal of BES1. We further found that B Deficiency reduces the accumulation of brassinolide (BL) by reducing BR6ox1 and BR6ox2 mRNA level to down-regulate BR signalling and modulate root elongation. Altogether, our results uncover a role of BR signalling in root elongation under B Deficiency. One-sentence summary B Deficiency reduces the accumulation of brassinolide by reducing BR6ox1 and BR6ox2 mRNA level to down-regulate BR signalling and modulate root elongation.
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Differential Alternative Splicing Genes in Response to Boron Deficiency in Brassica napus
2019Co-Authors: Sheliang Wang, Xiaoyan Zhang, Anne Coules, Guangda Ding, Jian Ren, Lei ShiAbstract:Alternative splicing (AS) can increase transcriptome diversity, protein diversity and protein yield, and is an important mechanism to regulate plant responses to stress. Oilseed rape (Brassica napus L.), one of the main oil crops in China, shows higher sensitivity to Boron (B) Deficiency than other species. Here, we demonstrated AS changes that largely increased the diversity of the mRNA expressed in response to B Deficiency in B. napus. Each gene had two or more transcripts on average. A total of 33.3% genes in both Qingyou10 (QY10, B-efficient cultivar) and Westar10 (W10, B-inefficient cultivar) showed AS in both B conditions. The types of AS events were mainly intron retention, 3′ alternative splice site, 5′ alternative splice site and exon skipping. The tolerance ability of QY10 was higher than that of W10, possibly because there were far more differential alternative splicing (DAS) genes identified in QY10 at low B conditions than in W10. The number of genes with both DAS and differentially expressed (DE) was far lower than that of the genes that were either with DAS or DE in QY10 and W10, suggesting that the DAS and DE genes were independent. Four Serine/Arginine-rich (SR) splicing factors, BnaC06g14780D, BnaA01g14750D, BnaA06g15930D and BnaC01g41640D, underwent differentially alternative splicing in both cultivars. There existed gene–gene interactions between BnaC06g14780D and the genes associated with the function of B in oilseed rape at low B supply. This suggests that oilseed rape could regulate the alterative pre-mRNA splicing of SR protein related genes to increase the plant tolerance to B Deficiency
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physiological genomic and transcriptional diversity in responses to Boron Deficiency in rapeseed genotypes
2016Co-Authors: Yingpeng Hua, Guangda Ding, Ting Zhou, Qingyong Yang, Lei ShiAbstract:Allotetraploid rapeseed (Brassica napus L. AnAnCnCn, 2n=4x=38) is highly susceptible to Boron (B) Deficiency, a widespread limiting factor that causes severe losses in seed yield. The genetic variation in the sensitivity to B Deficiency found in rapeseed genotypes emphasizes the complex response architecture. In this research, a B-inefficient genotype, 'Westar 10' ('W10'), responded to B deficiencies during vegetative and reproductive development with an over-accumulation of reactive oxygen species, severe lipid peroxidation, evident plasmolysis, abnormal floral organogenesis, and widespread sterility compared to a B-efficient genotype, 'Qingyou 10' ('QY10'). Whole-genome re-sequencing (WGS) of 'QY10' and 'W10' revealed a total of 1 605 747 single nucleotide polymorphisms and 218 755 insertions/deletions unevenly distributed across the allotetraploid rapeseed genome (~1130Mb). Digital gene expression (DGE) profiling identified more genes related to B transporters, antioxidant enzymes, and the maintenance of cell walls and membranes with higher transcript levels in the roots of 'QY10' than in 'W10' under B Deficiency. Furthermore, based on WGS and bulked segregant analysis of the doubled haploid (DH) line pools derived from 'QY10' and 'W10', two significant quantitative trait loci (QTLs) for B efficiency were characterized on chromosome C2, and DGE-assisted QTL-seq analyses then identified a nodulin 26-like intrinsic protein gene and an ATP-binding cassette (ABC) transporter gene as the corresponding candidates regulating B efficiency. This research facilitates a more comprehensive understanding of the differential physiological and transcriptional responses to B Deficiency and abundant genetic diversity in rapeseed genotypes, and the DGE-assisted QTL-seq analyses provide novel insights regarding the rapid dissection of quantitative trait genes in plant species with complex genomes.