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1.
Cell Mol Biol (Noisy-le-grand) ; 68(8): 182-190, 2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-36800839

RESUMO

The effect of phosphorus deficiency on plant growth, nodulation, and symbiotic nitrogen fixation as well as, the nodulated-roots oxygen consumption, nodule permeability and conductance to the oxygen diffusion of Medicago truncatula-Sinorhizobium meliloti symbiosis were studied. Three lines, namely TN6.18, originated from local populations, F83005.5 originated from Var (France) and Jemalong 6, a reference cultivar from Australia, were hydroponically grown in nutrient solution supplied with 5 µmol (P deficient) and 15 µmol (P sufficient: Control), under semi-controlled conditions in a glasshouse. A genotypic variation in tolerance to P deficiency was found: TN6.18 was the most tolerant line whereas F83005.5 was the most sensitive. The relative tolerance of TN6.18 was concomitant with the greater P requirement, the higher N2 fixation, the stimulation of nodule respiration and the less increases of conductance to the oxygen diffusion in nodules tissues. The higher P use efficiency for nodule growth and for symbiotic nitrogen fixation was detected in the tolerant line. Results suggest that the tolerance to P deficiency seems to depend on thehost plant ability to reallocate P from both leaves and roots to their nodules. P is needed in high energy demand conditions to maintain adequate nodule activity and prevent negative effects of the O2 excess on the nitrogenase.


Assuntos
Medicago truncatula , Nódulos Radiculares de Plantas , Nódulos Radiculares de Plantas/genética , Medicago truncatula/genética , Fósforo , Genótipo , Oxigênio
2.
Genomics ; 112(2): 1112-1119, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31242451

RESUMO

The rhizome of P. japonicus var. major, one of the important herbs in Traditional Chinese medicine (TCM), has been used as tonic and hemostatic drugs in Tujia and Miao ethnic groups of China for thousand years. In this study, comparative metabolite and transcriptome analysis of rhizome nodes and internodes of wild P. japonicus var. major was performed to reveal their different roles in the biosynthesis of triterpene saponins. The results showed that the node was the crucial section for the synthesis of ginsenosides in the rhizome. The content of oleanane-type ginsenosides in the node was much higher than those in the internode. Most isoprenoid biosynthesis-related genes were highly expressed in the node. And, candidate UDP-glycosyltransferase (UGT) genes were also found to be differentially expressed between node and internode. Our study will provide a better understanding of the metabolism of ginsenosides in the rhizome of P. japonicus var. major.


Assuntos
Ginsenosídeos/biossíntese , Panax/genética , Rizoma/genética , Transcriptoma , Ginsenosídeos/genética , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Metaboloma , Panax/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Rizoma/metabolismo , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/metabolismo
3.
J Plant Physiol ; 243: 153053, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31644998

RESUMO

Glutamate dehydrogenase (NAD(H)- GDH, EC 1.4.1.2) is an important enzyme in nitrogen (N) metabolism. It serves as a link between C and N metabolism, in its role of assimilating ammonia into glutamine or deaminating glutamate into 2-oxoglutarate and ammonia. GDH may also have a key in the N assimilation of legumes growing in P-poor soils. Virgilia divaricata is such a legume, growing in the nutrient limited soils of the mediterranean-type Cape fynbos ecosystem. In order to understand the role of GDH in the nitrogen nutrition of V. divaricata, the aim of this study was to identify the GDH gene transcripts, their relative expressions and enzyme activity in P-stressed roots and nodules during N metabolism. During P deficiency there was a reduction in total plant biomass as well as total plant P concentration. The analysis of the GDH cDNA sequences in V. divaricata revealed the presence of GHD1 and GHD2 subunits, these corresponding to the GDH1, GDH-B and GDH3 genes of legumes and non-legume plants. The relative expression of GDH1 and GDH2 genes in the roots and nodules, indicates that two the subunits were differently regulated depending on the organ type, rather than P supply. Although both transcripts appeared to be ubiquitously expressed in the roots and nodules, the GDH2 transcript evidently predominated over those of GDH1. Furthermore, the higher expression of both GDH transcripts in the roots than nodules, suggests that roots are more reliant on on GDH in P-poor soils, than nodules. With regards to GHD activity, both aminating and deaminating GDH activities were differently affected by P deficiency in roots and nodules. This may function to assimilate N and regulate internal C and N in the roots and nodules. The variation in GDH1 and GDH2 transcript expression and GDH enzyme activities, indicate that the enzyme may be regulated by post-translational modification, instead of by gene expression during P deficiency in V. divaricata.


Assuntos
Aclimatação , Fabaceae/fisiologia , Expressão Gênica , Glutamato Desidrogenase/genética , Fósforo/deficiência , Proteínas de Plantas/genética , Fabaceae/enzimologia , Fabaceae/genética , Glutamato Desidrogenase/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Nódulos Radiculares de Plantas/enzimologia , Nódulos Radiculares de Plantas/genética , África do Sul , Transcriptoma
4.
Int J Mol Sci ; 19(10)2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30261621

RESUMO

Phosphorus (P) deficiency is a major limitation for legume crop production. Although overall adaptations of plant roots to P deficiency have been extensively studied, only fragmentary information is available in regard to root nodule responses to P deficiency. In this study, genome wide transcriptome analysis was conducted using RNA-seq analysis in soybean nodules grown under P-sufficient (500 µM KH2PO4) and P-deficient (25 µM KH2PO4) conditions to investigate molecular mechanisms underlying soybean (Glycine max) nodule adaptation to phosphate (Pi) starvation. Phosphorus deficiency significantly decreased soybean nodule growth and nitrogenase activity. Nodule Pi concentrations declined by 49% in response to P deficiency, but this was well below the 87% and 88% decreases observed in shoots and roots, respectively. Nodule transcript profiling revealed that a total of 2055 genes exhibited differential expression patterns between Pi sufficient and deficient conditions. A set of (differentially expressed genes) DEGs appeared to be involved in maintaining Pi homeostasis in soybean nodules, including eight Pi transporters (PTs), eight genes coding proteins containing the SYG1/PHO81/XPR1 domain (SPXs), and 16 purple acid phosphatases (PAPs). The results suggest that a complex transcriptional regulatory network participates in soybean nodule adaption to Pi starvation, most notable a Pi signaling pathway, are involved in maintaining Pi homeostasis in nodules.


Assuntos
Perfilação da Expressão Gênica/métodos , Genoma de Planta/genética , Glycine max/genética , Homeostase , Fosfatos/metabolismo , Nódulos Radiculares de Plantas/genética , Adaptação Fisiológica/genética , Regulação da Expressão Gênica de Plantas , Fósforo/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Nódulos Radiculares de Plantas/metabolismo , Glycine max/metabolismo
5.
World J Microbiol Biotechnol ; 34(3): 37, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-29450655

RESUMO

Root endosymbioses are mutualistic interactions between plants and the soil microorganisms (Fungus, Frankia or Rhizobium) that lead to the formation of nitrogen-fixing root nodules and/or arbuscular mycorrhiza. These interactions enable many species to survive in different marginal lands to overcome the nitrogen-and/or phosphorus deficient environment and can potentially reduce the chemical fertilizers used in agriculture which gives them an economic, social and environmental importance. The formation and the development of these structures require the mediation of specific gene products among which the transcription factors play a key role. Three of these transcription factors, viz., CYCLOPS, NSP1 and NSP2 are well conserved between actinorhizal, legume, non-legume and mycorrhizal symbioses. They interact with DELLA proteins to induce the expression of NIN in nitrogen fixing symbiosis or RAM1 in mycorrhizal symbiosis. Recently, the small non coding RNA including micro RNAs (miRNAs) have emerged as major regulators of root endosymbioses. Among them, miRNA171 targets NSP2, a TF conserved in actinorhizal, legume, non-legume and mycorrhizal symbioses. This review will also focus on the recent advances carried out on the biological function of others transcription factors during the root pre-infection/pre-contact, infection or colonization. Their role in nodule formation and AM development will also be described.


Assuntos
Raízes de Plantas/genética , Raízes de Plantas/microbiologia , Simbiose/genética , Simbiose/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Agricultura , Proteínas de Arabidopsis , Proliferação de Células , Fabaceae/genética , Fabaceae/metabolismo , Fertilizantes , Frankia/metabolismo , Fungos/metabolismo , Genes Bacterianos , Genes Fúngicos , Genes de Plantas , MicroRNAs , Minociclina , Micorrizas/genética , Micorrizas/fisiologia , Nitrogênio/metabolismo , Fixação de Nitrogênio , Fósforo/metabolismo , Proteínas de Plantas/genética , Rhizobium/genética , Rhizobium/metabolismo , Rhizobium/fisiologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/microbiologia , Nódulos Radiculares de Plantas/fisiologia , Microbiologia do Solo
6.
Sci Rep ; 7: 46264, 2017 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-28393902

RESUMO

Nitrogen fixation of Medicago truncatula is regulated by the nitrogen status of leaves through inducing a repeatedly occurring 24-h nodule activity rhythm that reduces per day nitrogen fixation. The hypotheses of the present study were that (1) long-term moderate whole-plant P deficiency in Medicago truncatula induces an according daily rhythm in nitrogenase activity comparable to that induced by nitrate application and (2), the changes in the nodule transcriptome that go along with a strong nitrogenase activity decline during the afternoon would be similar under P deficiency or after nitrate supply. The nodules of plants in a low P treatment developed a rhythmic pattern of activity that resembled the pattern following nitrate application. A comprehensive, RNAseq-based comparative transcriptome profiling of nodules during a repeated part of the rhythm revealed similarities between P deficiency versus nitrate supply. Under both treatments, the formation of nitrogenase was targeted by a reduction in the expression of genes for nodule-specific cysteine-rich peptides (NCR), and possibly also by a disturbance of the inner cell iron allocation. A strong reduction in the expression of leghemoglobin is likely to have restricted the supply of oxygen for respiration.


Assuntos
Medicago truncatula/genética , Medicago truncatula/metabolismo , Nitratos/metabolismo , Fixação de Nitrogênio , Fósforo/deficiência , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/metabolismo , Biomassa , Regulação da Expressão Gênica de Plantas , Medicago truncatula/crescimento & desenvolvimento , Fósforo/metabolismo
7.
Physiol Plant ; 159(2): 215-227, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27762446

RESUMO

Induction of secreted and intracellular purple acid phosphatases (PAPs; EC 3.1.3.2) is widely recognized as an adaptation of plants to phosphorus (P) deficiency. The secretion of PAPs plays important roles in P acquisition. However, little is known about the functions of intracellular PAP in plants and nodules. In this study, we identified a novel PAP gene GmPAP21 in soybean. Expression of GmPAP21 was induced by P limitation in nodules, roots and old leaves, and increased in roots with increasing duration of P starvation. Furthermore, the induction of GmPAP21 in nodules and roots was more intensive than in leaves in both P-efficient genotype HN89 and P-inefficient genotype HN112 in response to P starvation, and the relative expression in the leaves and nodules of HN89 was significantly greater than that of HN112 after P deficiency treatment. Further functional analyses showed that over-expressing GmPAP21 significantly enhanced both acid phosphatase activity and growth performance of hairy roots under P starvation condition, indicating that GmPAP21 plays an important role in P utilization. Moreover, GUS expression driven by GmPAP21 promoter was shown in the nodules besides roots. Overexpression of GmPAP21 in transgenic soybean significantly inhibited nodule growth, and thereby affected plant growth after inoculation with rhizobia. This suggests that GmPAP21 is also possibly involved in regulating P metabolism in nodules. Taken together, our results suggest that GmPAP21 is a novel plant PAP that functions in the adaptation of soybean to P starvation, possibly through its involvement in P recycling in plants and P metabolism in nodules.


Assuntos
Fosfatase Ácida/metabolismo , Bradyrhizobium/fisiologia , Regulação da Expressão Gênica de Plantas , Glycine max/enzimologia , Glicoproteínas/metabolismo , Fósforo/metabolismo , Simbiose , Fosfatase Ácida/genética , Genes Reporter , Glicoproteínas/genética , Fósforo/deficiência , Folhas de Planta/citologia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/microbiologia , Plantas Geneticamente Modificadas , Nódulos Radiculares de Plantas/citologia , Nódulos Radiculares de Plantas/enzimologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/microbiologia , Glycine max/citologia , Glycine max/genética , Glycine max/microbiologia
8.
J Plant Physiol ; 205: 48-56, 2016 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-27614785

RESUMO

While increased P-hydrolysing acid phosphatases (APase) activity in bean nodules is well documented under phosphorus (P) limitation, gene expression and subcellular localization patterns within the N2-fixing nodule tissues are poorly understood. The aim of this research was to track the enzyme activity along with the intra-nodular localization of fructose-1,6-bisphosphatase (FBPase), and its contribution to P use efficiency (PUE) under symbiotic nitrogen fixation (SNF) in Phaseolus vulgaris. The FBPase transcript were localized in situ using RT-PCR and the protein activity was measured in nodules of two contrasting recombinant inbred lines (RILs) of P. vulgaris, namely RILs 115 (P-efficient) and 147 (P-inefficient), that were grown under sufficient versus deficient P supply. Under P-deficiency, higher FBPase transcript fluorescence was found in the inner cortex as compared to the infected zone of RIL115. In addition, both the specific FBPase and total APase enzyme activities significantly increased in both RILs, but to a more significant extent in RIL115 as compared to RIL147. Furthermore, the increased FBPase activity in nodules of RIL115 positively correlated with higher use efficiency of both the rhizobial symbiosis (23%) and P for SNF (14% calculated as the ratio of N2 fixed per nodule total P content). It is concluded that the abundant tissue-specific localized FBPase transcript along with induced enzymatic activity provides evidence of a specific tolerance mechanism where N2-fixing nodules overexpress under P-deficiency conditions. Such a mechanism would maximise the intra-nodular inorganic P fraction necessary to compensate for large amount of P needed during the SNF process.


Assuntos
Frutose-Bifosfatase/genética , Regulação da Expressão Gênica de Plantas , Phaseolus/enzimologia , Fósforo/metabolismo , Rhizobium/fisiologia , Frutose-Bifosfatase/metabolismo , Fixação de Nitrogênio , Phaseolus/citologia , Phaseolus/genética , Phaseolus/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Nódulos Radiculares de Plantas/citologia , Nódulos Radiculares de Plantas/enzimologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/microbiologia , Simbiose
9.
Protoplasma ; 252(6): 1505-17, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25743038

RESUMO

Rhizobia are able to establish a beneficial interaction with legumes by forming a new organ, called the symbiotic root nodule, which is a unique ecological niche for rhizobial nitrogen fixation. Rhizobial infection has many similarities with pathogenic infection and induction of defence responses accompanies both interactions, but defence responses are induced to a lesser extent during rhizobial infection. However, strong defence responses may result from incompatible interactions between legumes and rhizobia due to a mutation in either macro- or microsymbiont. The aim of this research was to analyse different plant defence reactions in response to Rhizobium infection for several pea (Pisum sativum) mutants that result in ineffective symbiosis. Pea mutants were examined by histochemical and immunocytochemical analyses, light, fluorescence and transmission electron microscopy and quantitative real-time PCR gene expression analysis. It was observed that mutations in pea symbiotic genes sym33 (PsIPD3/PsCYCLOPS encoding a transcriptional factor) and sym40 (PsEFD encoding a putative negative regulator of the cytokinin response) led to suberin depositions in ineffective nodules, and in the sym42 there were callose depositions in infection thread (IT) and host cell walls. The increase in deposition of unesterified pectin in IT walls was observed for mutants in the sym33 and sym42; for mutant in the sym42, unesterified pectin was also found around degrading bacteroids. In mutants in the genes sym33 and sym40, an increase in the expression level of a gene encoding peroxidase was observed. In the genes sym40 and sym42, an increase in the expression levels of genes encoding a marker of hypersensitive reaction and PR10 protein was demonstrated. Thus, a range of plant defence responses like suberisation, callose and unesterified pectin deposition as well as activation of defence genes can be triggered by different pea single mutations that cause perception of an otherwise beneficial strain of Rhizobium as a pathogen.


Assuntos
Regulação da Expressão Gênica de Plantas , Mutação , Pisum sativum/microbiologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/microbiologia , Rhizobium leguminosarum/fisiologia , Nódulos Radiculares de Plantas/microbiologia , Simbiose/genética , Fatores de Transcrição/genética , Genótipo , Glucanos/metabolismo , Imuno-Histoquímica , Lipídeos , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Fixação de Nitrogênio , Pisum sativum/genética , Pisum sativum/metabolismo , Pisum sativum/ultraestrutura , Pectinas/metabolismo , Fenótipo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/ultraestrutura , Reação em Cadeia da Polimerase em Tempo Real , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/metabolismo , Nódulos Radiculares de Plantas/ultraestrutura , Microbiologia do Solo , Fatores de Tempo
10.
J Exp Bot ; 65(20): 6035-48, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25151618

RESUMO

Legume nodules are plant tissues with an exceptionally high concentration of phosphorus (P), which, when there is scarcity of P, is preferentially maintained there rather than being allocated to other plant organs. The hypothesis of this study was that nodules are affected before the P concentration in the organ declines during whole-plant P depletion. Nitrogen (N2) fixation and P concentration in various organs were monitored during a whole-plant P-depletion process in Medicago truncatula. Nodule gene expression was profiled through RNA-seq at day 5 of P depletion. Until that point in time P concentration in leaves reached a lower threshold but was maintained in nodules. N2-fixation activity per plant diverged from that of fully nourished plants beginning at day 5 of the P-depletion process, primarily because fewer nodules were being formed, while the activity of the existing nodules was maintained for as long as two weeks into P depletion. RNA-seq revealed nodule acclimation on a molecular level with a total of 1140 differentially expressed genes. Numerous genes for P remobilization from organic structures were increasingly expressed. Various genes involved in nodule malate formation were upregulated, while genes involved in fermentation were downregulated. The fact that nodule formation was strongly repressed with the onset of P deficiency is reflected in the differential expression of various genes involved in nodulation. It is concluded that plants follow a strategy to maintain N2 fixation and viable leaf tissue as long as possible during whole-plant P depletion to maintain their ability to react to emerging new P sources (e.g. through active P acquisition by roots).


Assuntos
Regulação da Expressão Gênica de Plantas , Medicago truncatula/genética , Fósforo/deficiência , Sinorhizobium meliloti/fisiologia , Transcriptoma , Aclimatação , Medicago truncatula/microbiologia , Medicago truncatula/fisiologia , Nitrogênio/metabolismo , Fixação de Nitrogênio , Fenótipo , Fósforo/metabolismo , Folhas de Planta/genética , Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Nodulação , Raízes de Plantas/genética , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/microbiologia , Nódulos Radiculares de Plantas/fisiologia , Análise de Sequência de RNA , Simbiose
11.
J Plant Physiol ; 171(17): 1609-18, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-25151130

RESUMO

During P deficiency, the increased activity of malate dehydrogenase (MDH, EC 1.1.1.37) can lead to malate accumulation. Cytosolic- and nodule-enhanced MDH (cMDH and neMDH, respectively) are known isoforms, which contribute to MDH activity in root nodules. The aim of this study was to investigate the role of the cMDH isoforms in nodule malate supply under P deficiency. Nodulated lupins (Lupinus angustifolius var. Tanjil) were hydroponically grown at adequate P (+P) or low P (-P). Total P concentration in nodules decreased under P deficiency, which coincided with an increase in total MDH activity. A consequence of higher MDH activity was the enhanced accumulation of malate derived from dark CO2 fixation via PEPC and not from pyruvate. Although no measurable neMDH presence could be detected via PCR, gene-specific primers detected two 1kb amplicons of cMDH, designated LangMDH1 (corresponding to +P, HQ690186) and LangMDH2 (corresponding to -P, HQ690187), respectively. Sequencing analyses of these cMDH amplicons showed them to be 96% identical on an amino acid level. There was a high degree of diversification between proteins detected in this study and other known MDH proteins, particularly those from other leguminous plants. Enhanced malate synthesis in P-deficient nodules was achieved via increased anaplerotic CO2 fixation and subsequent higher MDH activities. Novel isoforms of cytosolic MDH may be involved, as shown by gene expression of specific genes under P deficiency.


Assuntos
Lupinus/enzimologia , Malato Desidrogenase/genética , Malatos/metabolismo , Fósforo/deficiência , Sequência de Aminoácidos , Sequência de Bases , Citosol/enzimologia , DNA Complementar/química , DNA Complementar/genética , DNA de Plantas/química , DNA de Plantas/genética , Hidroponia , Isoenzimas , Lupinus/genética , Malato Desidrogenase/metabolismo , Dados de Sequência Molecular , Fixação de Nitrogênio , Fósforo/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA de Plantas/genética , Nódulos Radiculares de Plantas/enzimologia , Nódulos Radiculares de Plantas/genética , Alinhamento de Sequência , Análise de Sequência de DNA
12.
Planta ; 238(2): 317-24, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23677567

RESUMO

Phosphorus is an essential nutrient for rhizobial symbioses to convert N2 into NH4 usable for N nutrition in legumes and N cycle in ecosystems. This N2 fixation process occurs in nodules with a high energy cost. Phytate is the major storage form of P and accounts for more than 50 % of the total P in seeds of cereals and legumes. The phytases, a group of enzymes widely distributed in plant and microorganisms, are able to hydrolyze a variety of inositol phosphates. Recently, phytase activity was discovered in nodules. However, the gene expression localization and its role in N2-fixing nodules are still unknown. In this work, two recombinant inbred lines (RILs) of common bean (Phaseolus vulgaris L.), selected as contrasting for N2 fixation under P deficiency, namely RILs 115 (P-efficient) and 147 (P-inefficient) were inoculated with Rhizobium tropici CIAT 899, and grown under hydroaeroponic conditions with sufficient versus deficient P supply. With in situ RT-PCR methodology, we found that phytase transcripts were particularly abundant in the nodule cortex and infected zone of both RILs. Under P deficiency, phytase transcripts were significantly more abundant for RIL115 than for RIL147, and more in the outer cortex than in the infected zone. Additionally, the high expression of phytase among nodule tissues for the P-deficient RIL115 was associated with an increase in phytase (33 %) and phosphatase (49 %) activities and efficiency in use of the rhizobial symbiosis (34 %). It is argued that phytase activity in nodules would contribute to the adaptation of the rhizobia-legume symbiosis to low-P environments.


Assuntos
6-Fitase/genética , Regulação Enzimológica da Expressão Gênica , Nitrogênio/metabolismo , Phaseolus/enzimologia , Fósforo/deficiência , Rhizobium/fisiologia , 6-Fitase/metabolismo , Regulação da Expressão Gênica de Plantas , Endogamia , Nitrogênio/análise , Fixação de Nitrogênio , Phaseolus/citologia , Phaseolus/genética , Phaseolus/fisiologia , Fósforo/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA de Plantas/genética , Nódulos Radiculares de Plantas/citologia , Nódulos Radiculares de Plantas/enzimologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/fisiologia , Análise de Sequência de DNA , Simbiose
13.
J Exp Bot ; 63(13): 4723-30, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22771853

RESUMO

Although previous studies on N2-fixing legumes have demonstrated the contribution of acid phosphatases to their phosphorus (P) use efficiency under P-deficient growth conditions, localization of these enzymes in bean nodules has not been demonstrated. In this study, phosphoenol pyruvate phosphatase (PEPase) gene transcripts were localized within the nodule tissues of two recombinant inbred lines, RIL115 (P-deficiency tolerant) and RIL147 (P-deficiency sensitive), of Phaseolus vulgaris. Nodules were induced by Rhizobium tropici CIAT899 under hydroaeroponic conditions with a sufficient versus a deficient P supply. The results indicated that PEPase transcripts were particularly abundant in the nodule infected zone and cortex of both RILs. Analysis of fluorescence intensity indicated that nodule PEPase was induced under conditions of P deficiency to a significantly higher extent in RIL147 than in RIL115, and more in the inner cortex (91%) than in the outer cortex (71%) or the infected zone (79%). In addition, a significant increase (39%) in PEPase enzyme activity in the P-deficient RIL147 correlated with an increase (58%) in the efficiency of use in rhizobial symbiosis. It was concluded that nodule PEPase is upregulated under conditions of P deficiency in the P-deficiency-sensitive RIL147, and that this gene may contribute to adaptation of rhizobial symbiosis to low-P environments.


Assuntos
Fosfatase Ácida/genética , Phaseolus/enzimologia , Fósforo/deficiência , Rhizobium tropici/fisiologia , Fosfatase Ácida/metabolismo , Adaptação Fisiológica , Endogamia , Nitrogênio/metabolismo , Fixação de Nitrogênio/genética , Phaseolus/citologia , Phaseolus/genética , Phaseolus/crescimento & desenvolvimento , Fósforo/análise , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Nodulação , Raízes de Plantas/citologia , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/citologia , Brotos de Planta/enzimologia , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , RNA Mensageiro/genética , RNA de Plantas/genética , Nódulos Radiculares de Plantas/citologia , Nódulos Radiculares de Plantas/enzimologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/crescimento & desenvolvimento , Plântula/citologia , Plântula/enzimologia , Plântula/genética , Plântula/crescimento & desenvolvimento , Simbiose
14.
Plant Physiol ; 159(4): 1634-43, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22740613

RESUMO

Legume biological nitrogen (N) fixation is the most important N source in agroecosystems, but it is also a process requiring a considerable amount of phosphorus (P). Therefore, developing legume varieties with effective N(2) fixation under P-limited conditions could have profound significance for improving agricultural sustainability. We show here that inoculation with effective rhizobial strains enhanced soybean (Glycine max) N(2) fixation and P nutrition in the field as well as in hydroponics. Furthermore, we identified and characterized a nodule high-affinity phosphate (Pi) transporter gene, GmPT5, whose expression was elevated in response to low P. Yeast heterologous expression verified that GmPT5 was indeed a high-affinity Pi transporter. Localization of GmPT5 expression based on ß-glucuronidase staining in soybean composite plants with transgenic roots and nodules showed that GmPT5 expression occurred principally in the junction area between roots and young nodules and in the nodule vascular bundles for juvenile and mature nodules, implying that GmPT5 might function in transporting Pi from the root vascular system into nodules. Overexpression or knockdown of GmPT5 in transgenic composite soybean plants altered nodulation and plant growth performance, which was partially dependent on P supply. Through both in situ and in vitro (33)P uptake assays using transgenic soybean roots and nodules, we demonstrated that GmPT5 mainly functions in transporting Pi from roots to nodules, especially under P-limited conditions. We conclude that the high-affinity Pi transporter, GmPT5, controls Pi entry from roots to nodules, is critical for maintaining Pi homeostasis in nodules, and subsequently regulates soybean nodulation and growth performance.


Assuntos
Glycine max/fisiologia , Proteínas de Transporte de Fosfato/metabolismo , Fosfatos/metabolismo , Proteínas de Plantas/metabolismo , Nodulação/fisiologia , Nódulos Radiculares de Plantas/metabolismo , Bioensaio , Transporte Biológico , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Glucuronidase/metabolismo , Hidroponia , Dados de Sequência Molecular , Nitrogênio/metabolismo , Proteínas de Transporte de Fosfato/genética , Fósforo/metabolismo , Proteínas de Plantas/genética , Nodulação/genética , Plantas Geneticamente Modificadas , Interferência de RNA , Rhizobium/fisiologia , Nódulos Radiculares de Plantas/genética , Saccharomyces cerevisiae/metabolismo , Solubilidade , Glycine max/genética , Glycine max/crescimento & desenvolvimento , Glycine max/microbiologia , Supressão Genética
15.
Proteomics ; 11(24): 4648-59, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22002838

RESUMO

Symbiotic nitrogen fixation is a high-phosphorus demand process. Proteomic analysis was performed to identify the differentially expressed proteins in soybean nodules under phosphate starvation, and qRT-PCR was subsequently conducted to examine the expression patterns of the genes encoding the identified proteins. There were 44 phosphate-starvation responsive proteins identified from soybean nodules. Among them, 14 plant and 3 rhizobial proteins were up-regulated, whereas 13 plant and 14 rhizobial proteins were down-regulated by phosphate starvation. The qRT-PCR assays verified that gene expression correlated with 11 of the 14 up-regulated proteins from plants, but only 4 of 13 down-regulated proteins were correlated to the expression of the corresponding genes, suggesting that most up-regulated proteins may be controlled at the transcriptional level, whereas down-regulated proteins were controlled at the post-transcriptional level. Furthermore, a group of genes exhibited differential responses to phosphate starvation in nodules versus roots, suggesting that different adaptive responses might occur between roots and nodules. To our best knowledge, this is the first study to reveal differential protein profiles of nodules responding to phosphate starvation through proteomic analysis, which could result in a relatively comprehensive understanding of molecular mechanisms through which soybean nodules adapt to phosphorus stress.


Assuntos
Glycine max/genética , Fósforo/deficiência , Nódulos Radiculares de Plantas/metabolismo , Proteínas de Soja/análise , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Fixação de Nitrogênio/genética , Proteômica/métodos , Nódulos Radiculares de Plantas/genética , Proteínas de Soja/genética , Proteínas de Soja/metabolismo , Glycine max/crescimento & desenvolvimento , Glycine max/metabolismo , Estresse Fisiológico/genética
16.
Theor Appl Genet ; 121(1): 71-86, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20180092

RESUMO

Pea (Pisum sativum L.) is the third most important grain legume worldwide, and the increasing demand for protein-rich raw material has led to a great interest in this crop as a protein source. Seed yield and protein content in crops are strongly determined by nitrogen (N) nutrition, which in legumes relies on two complementary pathways: absorption by roots of soil mineral nitrogen, and fixation in nodules of atmospheric dinitrogen through the plant-Rhizobium symbiosis. This study assessed the potential of naturally occurring genetic variability of nodulated root structure and functioning traits to improve N nutrition in pea. Glasshouse and field experiments were performed on seven pea genotypes and on the 'Cameor' x 'Ballet' population of recombinant inbred lines selected on the basis of parental contrast for root and nodule traits. Significant variation was observed for most traits, which were obtained from non-destructive kinetic measurements of nodulated root and shoot in pouches, root and shoot image analysis, (15)N quantification, or seed yield and protein content determination. A significant positive relationship was found between nodule establishment and root system growth, both among the seven genotypes and the RIL population. Moreover, several quantitative trait loci for root or nodule traits and seed N accumulation were mapped in similar locations, highlighting the possibility of breeding new pea cultivars with increased root system size, sustained nodule number, and improved N nutrition. The impact on both root or nodule traits and N nutrition of the genomic regions of the major developmental genes Le and Af was also underlined.


Assuntos
Nitrogênio/metabolismo , Pisum sativum , Raízes de Plantas , Brotos de Planta , Locos de Características Quantitativas , Nódulos Radiculares de Plantas , Genes de Plantas , Variação Genética , Genótipo , Fixação de Nitrogênio/fisiologia , Pisum sativum/anatomia & histologia , Pisum sativum/genética , Pisum sativum/metabolismo , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Brotos de Planta/genética , Brotos de Planta/metabolismo , Nódulos Radiculares de Plantas/anatomia & histologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/metabolismo
17.
Plant Physiol ; 151(3): 1221-38, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19755543

RESUMO

Phosphorus (P) deficiency is widespread in regions where the common bean (Phaseolus vulgaris), the most important legume for human consumption, is produced, and it is perhaps the factor that most limits nitrogen fixation. Global gene expression and metabolome approaches were used to investigate the responses of nodules from common bean plants inoculated with Rhizobium tropici CIAT899 grown under P-deficient and P-sufficient conditions. P-deficient inoculated plants showed drastic reduction in nodulation and nitrogenase activity as determined by acetylene reduction assay. Nodule transcript profiling was performed through hybridization of nylon filter arrays spotted with cDNAs, approximately 4,000 unigene set, from the nodule and P-deficient root library. A total of 459 genes, representing different biological processes according to updated annotation using the UniProt Knowledgebase database, showed significant differential expression in response to P: 59% of these were induced in P-deficient nodules. The expression platform for transcription factor genes based in quantitative reverse transcriptase-polymerase chain reaction revealed that 37 transcription factor genes were differentially expressed in P-deficient nodules and only one gene was repressed. Data from nontargeted metabolic profiles indicated that amino acids and other nitrogen metabolites were decreased, while organic and polyhydroxy acids were accumulated, in P-deficient nodules. Bioinformatics analyses using MapMan and PathExpress software tools, customized to common bean, were utilized for the analysis of global changes in gene expression that affected overall metabolism. Glycolysis and glycerolipid metabolism, and starch and Suc metabolism, were identified among the pathways significantly induced or repressed in P-deficient nodules, respectively.


Assuntos
Fixação de Nitrogênio/genética , Phaseolus/metabolismo , Fósforo/metabolismo , Simbiose , Biologia Computacional , Etiquetas de Sequências Expressas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Biblioteca Gênica , Genes de Plantas , Metaboloma , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Phaseolus/genética , Fósforo/deficiência , RNA de Plantas/metabolismo , Rhizobium tropici , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/metabolismo , Análise de Sequência de DNA , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Mol Plant Microbe Interact ; 21(4): 375-82, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18321183

RESUMO

In this study, we compared the transcriptional activities between Cauliflower mosaic virus (CaMV)35S promoter and polyubiquitin (Ljubq1) promoter from Lotus japonicus using beta-glucuronidase (gus) reporter gene in transgenic plants of L. japonicus. The promoter analysis demonstrated that the Ljubq1 promoter possessed higher activity than the CaMV35S promoter in leaves, stems, roots, nodules, and pollen. Finally, we created GATEWAY conversion technology-compatible binary vectors for over-expression and RNA interference under the Ljubq1 promoter. These materials could provide alternative choice for studies in L. japonicus.


Assuntos
Inativação Gênica , Vetores Genéticos/genética , Lotus/genética , Poliubiquitina/genética , Regiões Promotoras Genéticas/genética , Caulimovirus/genética , Lotus/citologia , Modelos Genéticos , Folhas de Planta/genética , Raízes de Plantas/genética , Caules de Planta/genética , Plantas Geneticamente Modificadas , Pólen/genética , Nódulos Radiculares de Plantas/genética
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