Inhibition of glutamine synthetase leads to a fast transcriptional activation of defense responses in root nodules

Seabra, Ana R.; Carvalho, Helena

doi:10.1002/9781119409144.ch82

Cited by 3 publications

(3 citation statements)

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“…Furthermore, the presence of mannitol in our study is significantly correlated with bacteria composition in adult trees and it has been described as a key component in plant defense [54]. Otherwise, several works have studied the role of glutamine amino acid in the activation of defense responses of the plant against pathogens where the deficit of glutamine is linked to the inhibition of glutamine synthetase complex activating plant defense genes [55,56], or the antibacterial activity of acetic acid that supports flavonoid and lipid biosynthesis [57,58]. In relation to ions, K and Cl − were the element and inorganic anion more abundant, respectively.…”

Section: Discussionmentioning

confidence: 68%

Metabolomic, Ionomic and Microbial Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

et al. 2021

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Vascular pathogens are the causal agents of main diseases threatening the health and growth of olive crops worldwide. The use of endophytic microorganisms represents a challenging and promising strategy for management of vascular diseases in olive. Although current research has been focused on analyzing the structure and diversity of the endophytic microbial communities inhabiting the olive xylem, the characterization of this ecological niche has been overlooked and to date remain unexplored, despite that the characterization of the xylem sap composition is essential to unravel the nutritional requirements of xylem-limited microorganisms. In this study, branches from plantlets and adult olive trees of cultivars Picual and Arbequina were selected to characterize the chemical and microbial composition of olive xylem sap extracted using a Scholander pressure chamber. Metabolome and ionome analyses of xylem sap were performed by proton nuclear magnetic resonance (NMR) spectroscopy-based and by inductively coupled plasma with optical emission spectroscopy (ICP-OES), respectively. Olive xylem sap metabolites included a higher relative percentage of sugars (54.35%), followed by alcohols (28.85%), amino acids (8.01%), organic acids (7.68%), and osmolytes (1.12%). Within each of these groups, the main metabolites in the olive xylem sap were mannitol, ethanol, glutamine, acetic acid, and trigonelline, whereas K and Cl− were the main element and inorganic anion, respectively. Metabolomic profile varied when comparing olive plant age and genotype. The levels of glucose, fructose, sucrose and mannitol, choline, B and PO43− were significantly higher in adult trees than in plantlets for both olive genotypes, whereas NO3− and Rb content showed the opposite behavior. On the other hand, levels of aspartic acid, phenylalanine, and Na were significantly higher in ‘Picual’ than in ‘Arbequina’, whereas Fe showed the opposite behavior, but only for adult trees. Microbiome composition identified Firmicutes (67%), Proteobacteria (22%) and Actinobacteriota (11%) as the main phyla, while at the genus level Anoxybacillus (52%), Cutibacterium (7%), Massilia (6%), and Pseudomonas (3%) were the most representative. Both non-supervised hierarchical clustering analysis and supervised PLS-DA analysis differentiated xylem sap chemical and microbial composition first, according to the age of the plant and then by the olive genotype. PLS-DA analysis revealed that B, ethanol, Fe, fructose, glucose, mannitol, sucrose, and Sr, and Anoxybacillus, Cutibacterium, and Bradyrhizobium were the most significant chemical compounds and bacterial genera, respectively, in the discrimination of adult olive trees and plantlets. Knowledge of the chemical composition of xylem sap will lead to a better understanding of the complex nutritional requirements of olive xylem-inhabiting microorganisms, including vascular pathogens and their potential antagonists, and may allow the better design of artificial growing media to improve the culturing of the olive microbiome.

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Section: Discussionmentioning

confidence: 68%

Metabolomic, Ionomic and Microbial Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

et al. 2021

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“…Thus, mannitol is known as an osmoregulator being synthesized by plants in response to dehydration conditions [41] and has a remarkable role in protecting plant cells against damage by reactive oxygen species (ROS) [42]. Otherwise, several works have studied the role of glutamine amino acid in the activation of defense responses of the plant against pathogens where the deficit of glutamine is linked to the inhibition of glutamine synthetase complex activating plant defense genes [43,44]; or the antibacterial activity of acetate that supports flavonoid and lipid biosynthesis [45,46]. In relation to ions, K and Clwere the element and inorganic anion more abundant, respectively.…”

Section: Discussionmentioning

confidence: 99%

Metabolomic Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

Anguita-Maeso¹,

Haro²,

Montes-Borrego³

et al. 2021

Preprint

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Vascular pathogens are the causal agents of main diseases threatening the health and growth of olive crops worldwide. The use of endophytic microorganisms represents a challenging and promising strategy for management of vascular diseases in olive. Although current research has been focused on analyzing the structure and diversity of the endophytic microbial communities inhabiting the olive xylem, the characterization of this ecological niche has been overlooked and to date remain unexplored, despite that the characterization of the xylem sap composition is essential to unravel the nutritional requirements of xylem-limited microorganisms. In this study, branches from plantlets and adult olive trees of cultivars ‘Picual’ and ‘Arbequina' were selected to characterize the chemical composition of olive xylem sap extracted using a Scholander pressure chamber. Metabolome and ionome analyses of xylem sap were performed by proton nuclear magnetic resonance (NMR) spectroscopy-based and by inductively coupled plasma with optical emission spectroscopy (ICP-OES), respectively. Olive xylem sap metabolites included a higher relative percentage of sugars (54.35%), followed by alcohols (28.85%), amino acids (8.01%), organic acids (7.68%) and osmolytes (1.12%). Within each of these groups, the main metabolites in the olive xylem sap were mannitol, ethanol, glutamine, acetate and trigonelline, whereas K and Cl- were the main element and inorganic anion, respectively. Metabolomic profile varied when comparing olive plant age and genotype. The levels of glucose, fructose, sucrose and mannitol, choline, B and PO43 were significantly higher in adult trees than in plantlets for both olive genotypes, whereas NO3- and Rb content showed the opposite behavior. On the other hand, levels of aspartate, phenylalanine and Na were significantly higher in ‘Picual’ than in ‘Arbequina’ whereas Fe showed the opposite behavior but only for adult trees. Non-supervised hierarchical clustering analysis separated xylem sap composition firstly according to the plant age and then by the olive cultivar. Supervised PLS-DA analysis revealed that B, ethanol, Fe, Fructose, glucose, mannitol, sucrose and Sr were the most significative compounds discriminating adult trees from plantlets, whereas asparagine, aspartate, glutamate and phenylalanine or aspartate, arginine, ethanol and Sr were the most contributory compounds in the discrimination of both olive genotypes for adult trees or plantlets, respectively. Knowledge of the chemical composition of xylem sap will lead to a better understanding of the complex nutritional requirements of olive xylem-inhabiting microorganisms, including its vascular pathogens, and would allow the design of artificial growing media to improve culturing the olive microbiome.

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“…CA promotes the utilization efficiency of inorganic carbon during photosynthesis by regulating intracellular and extracellular inorganic carbon concentrations. Although the conversion of nitrate to nitrite was slightly inhibited by LL2, the highly induced expression of CA, NirA, and GLUL revealed superior carbon and nitrogen utilization efficiency in G9 plants (Lardi et al 2016;Seabra and Carvalho 2019), which is one of the reasons for the high yield of G9.…”

Section: Ll2 Regulates Specific Expression Of Genes Related To Nitrog...mentioning

confidence: 99%

Fine-Tuned Immune Antagonism and Nodule-Specific Cysteine-Rich Peptides Govern the Symbiotic Specificity Between Alfalfa Cultivars and Ensifer meliloti

Kang

Zhang

et al. 2022

J Plant Growth Regul

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Alfalfa expresses significantly distinct sets of genes in response to infection with different rhizobial strains at the below species level (i.e., biotype or strain). However, differences in the transcriptomic profiles of two alfalfa cultivars nodulated by a single rhizobium strain have been largely unexamined. In this study, comparative RNA-seq analysis of two alfalfa cultivars, Medicago sativa cv. Gannong No. 3 (G3) and cv. Gannong No. 9 (G9) inoculated with one Ensifer meliloti strain LL2, with varying symbiotic performance, was conducted, followed by hub gene interaction network construction based on weighted gene co-expression network analysis (WGCNA). The G9-LL2 symbiotic system showed better nodule formation, nitrogen fixation, and growth characteristics than the G3-LL2 system. Compared with the non-inoculated control, the LL2-inoculated G9 plants (10,053) produced more differentially expressed genes (DEGs) than the LL2-inoculated G3 plants (7112). A group of 227 genes displayed completely distinguished expression in G9 (6.63 < log2(FC) < 15.45) and G3 (‒ 3.05 < log2(FC) < 12.05), which are primarily involved in encoding nodule-specific cysteine-rich peptides (NCRs), nodulin, and leghemoglobin. Although genes with predicted roles in nitrogen metabolism were primarily upregulated and almost all of those in ubiquitin-mediated proteolysis and plant–pathogen interaction were suppressed, interestingly, a consistently higher expression level measured by log2(FC) was observed in G9 plants. Hub gene interaction networks showed that NCRs, late nodulin, and genes related to plant immunity (TIR-NBS-LRR, defensin, thioredoxin, thionine, and polygalacturonase) regulate other genes at the source node positions. After successful initiation of nodulation in both alfalfa cultivars G3 and G9 by E. meliloti strain LL2, G9 achieved preferable outcomes of rhizobia–alfalfa symbiosis by equilibrating the antagonism and compatibility of plant immunity. It elevated PTI, suppressed defense and ETI, and enhanced nitrogen fixation and utilization efficiency by inducing the expression of genes encoding NIN, NFH1, LysM-RLK, LRP, NCRs, nodulin, and leghemoglobin. Hub genes were predominantly associated with highly specific rhizobia–alfalfa symbiosis positively governed by NCRs and fine-tuned immune antagonism, comprising NCRs, late nodulin, and TIR-NBS-LRR. These findings provide insights into the genetic mechanisms underlying the modification and efficient utilization of semi-compatible and incompatible rhizobial resources.

show abstract

Inhibition of glutamine synthetase leads to a fast transcriptional activation of defense responses in root nodules

Cited by 3 publications

References 51 publications

Metabolomic, Ionomic and Microbial Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

Metabolomic, Ionomic and Microbial Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

Metabolomic Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

Fine-Tuned Immune Antagonism and Nodule-Specific Cysteine-Rich Peptides Govern the Symbiotic Specificity Between Alfalfa Cultivars and Ensifer meliloti

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