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Metabolic Profile and Root Development of Hypericum perforatum L. In vitro Roots under Stress Conditions Due to Chitosan Treatment and Culture Time.

Brasili E, Miccheli A, Marini F, Praticò G, Sciubba F, Di Cocco ME, Cechinel VF, Tocci N, Valletta A, Pasqua G - Front Plant Sci (2016)

Bottom Line: In response to the increase of biomass density over time, a decrease in the synthesis of isoleucine, valine, pyruvate, methylamine, etanolamine, trigonelline, glutamine and fatty acids, and an increase in the synthesis of phenolic compounds, such as xanthones, epicatechin, gallic, and shikimic acid were observed.Chitosan treatment associated to a slowdown of root biomass growth caused an increase in DMAPP and a decrease in stigmasterol, shikimic acid, and tryptophan levels.Most of the metabolic variations as well as the morpho-anatomical alterations occurred within 72 h from the elicitation, suggesting an early response of H. perforatum roots to chitosan elicitation.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Biology, "Sapienza" University of Rome Rome, Italy.

ABSTRACT
The responses of Hypericum perforatum root cultures to chitosan elicitation had been investigated through (1)H-NMR-based metabolomics associated with morpho-anatomical analyses. The root metabolome was influenced by two factors, i.e., time of culture (associated with biomass growth and related "overcrowding stress") and chitosan elicitation. ANOVA simultaneous component analysis (ASCA) modeling showed that these factors act independently. In response to the increase of biomass density over time, a decrease in the synthesis of isoleucine, valine, pyruvate, methylamine, etanolamine, trigonelline, glutamine and fatty acids, and an increase in the synthesis of phenolic compounds, such as xanthones, epicatechin, gallic, and shikimic acid were observed. Among the xanthones, brasilixanthone B has been identified for the first time in chitosan-elicited root cultures of H. perforatum. Chitosan treatment associated to a slowdown of root biomass growth caused an increase in DMAPP and a decrease in stigmasterol, shikimic acid, and tryptophan levels. The histological analysis of chitosan-treated roots revealed a marked swelling of the root apex, mainly due to the hypertrophy of the first two sub-epidermal cell layers. In addition, periclinal divisions in hypertrophic cortical cells, resulting in an increase of cortical layers, were frequently observed. Most of the metabolic variations as well as the morpho-anatomical alterations occurred within 72 h from the elicitation, suggesting an early response of H. perforatum roots to chitosan elicitation. The obtained results improve the knowledge of the root responses to biotic stress and provide useful information to optimize the biotechnological production of plant compounds of industrial interest.

No MeSH data available.


Related in: MedlinePlus

Schematic representation of root metabolic network. The metabolic pathway involved in time-dependent response of root cultures to the stress condition are shown in gray boxes: the upward arrows indicate a positive regulation and the downward arrows a negative regulation of metabolic pathways as well as the significantly increase and the decrease in metabolite levels. The white arrows indicate the metabolic variations depending on the culture time; the black arrows indicate the metabolic variations depending on the chitosan treatment. PEP, phosphoenolpyruvate; BCAA, branched-chain aminoacids; DMAPP, dimethylallyl-pyrophosphate.
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Figure 6: Schematic representation of root metabolic network. The metabolic pathway involved in time-dependent response of root cultures to the stress condition are shown in gray boxes: the upward arrows indicate a positive regulation and the downward arrows a negative regulation of metabolic pathways as well as the significantly increase and the decrease in metabolite levels. The white arrows indicate the metabolic variations depending on the culture time; the black arrows indicate the metabolic variations depending on the chitosan treatment. PEP, phosphoenolpyruvate; BCAA, branched-chain aminoacids; DMAPP, dimethylallyl-pyrophosphate.

Mentions: Furthermore, the observation of a browning of the biomass and the culture medium, accompanied to the slowdown of biomass growth in both treated and untreated roots, suggests that these stress responses could be referred to aging phenomena (Comas et al., 2010). In treated roots, aging processes could be linked to the stress caused by chitosan, whereas in control roots it could be related to the stress caused by the high biomass density (overcrowding stress). It should be stressed that, the SC1 loadings for the “time effect” highlighted the relationship among the changes in primary and secondary metabolism due to common phenomena occurring in both untreated and treated roots and depending on two different stresses, i.e., high biomass density and chitosan treatment. These metabolic variations suggest that two stresses affected the utilization of glycolytic intermediates and acetyl-CoA for the synthesis of amino acids and fatty acids, shifting the glucose metabolism from the glycolysis to the pentose phosphate pathway for the production of secondary metabolites. The response of root cultures to the stress conditions is displayed in Figure 6. Along the SC2, the significant metabolic variations regarding leucine, threonine, alanine, pyruvate, and glucose, as well as methylamine and adenosine displayed a biphasic pattern, mainly pronounced in chitosan-treated roots. Since these metabolites increased or decreased until to 72 h after chitosan elicitation and then progressively returned to their original level, a transient effect of chitosan on primary metabolism can be suggested. In other words the SC2 scores mainly describe the time-dependent changes of the metabolite levels occurring in the chitosan-treated roots before and after 72 h.


Metabolic Profile and Root Development of Hypericum perforatum L. In vitro Roots under Stress Conditions Due to Chitosan Treatment and Culture Time.

Brasili E, Miccheli A, Marini F, Praticò G, Sciubba F, Di Cocco ME, Cechinel VF, Tocci N, Valletta A, Pasqua G - Front Plant Sci (2016)

Schematic representation of root metabolic network. The metabolic pathway involved in time-dependent response of root cultures to the stress condition are shown in gray boxes: the upward arrows indicate a positive regulation and the downward arrows a negative regulation of metabolic pathways as well as the significantly increase and the decrease in metabolite levels. The white arrows indicate the metabolic variations depending on the culture time; the black arrows indicate the metabolic variations depending on the chitosan treatment. PEP, phosphoenolpyruvate; BCAA, branched-chain aminoacids; DMAPP, dimethylallyl-pyrophosphate.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835506&req=5

Figure 6: Schematic representation of root metabolic network. The metabolic pathway involved in time-dependent response of root cultures to the stress condition are shown in gray boxes: the upward arrows indicate a positive regulation and the downward arrows a negative regulation of metabolic pathways as well as the significantly increase and the decrease in metabolite levels. The white arrows indicate the metabolic variations depending on the culture time; the black arrows indicate the metabolic variations depending on the chitosan treatment. PEP, phosphoenolpyruvate; BCAA, branched-chain aminoacids; DMAPP, dimethylallyl-pyrophosphate.
Mentions: Furthermore, the observation of a browning of the biomass and the culture medium, accompanied to the slowdown of biomass growth in both treated and untreated roots, suggests that these stress responses could be referred to aging phenomena (Comas et al., 2010). In treated roots, aging processes could be linked to the stress caused by chitosan, whereas in control roots it could be related to the stress caused by the high biomass density (overcrowding stress). It should be stressed that, the SC1 loadings for the “time effect” highlighted the relationship among the changes in primary and secondary metabolism due to common phenomena occurring in both untreated and treated roots and depending on two different stresses, i.e., high biomass density and chitosan treatment. These metabolic variations suggest that two stresses affected the utilization of glycolytic intermediates and acetyl-CoA for the synthesis of amino acids and fatty acids, shifting the glucose metabolism from the glycolysis to the pentose phosphate pathway for the production of secondary metabolites. The response of root cultures to the stress conditions is displayed in Figure 6. Along the SC2, the significant metabolic variations regarding leucine, threonine, alanine, pyruvate, and glucose, as well as methylamine and adenosine displayed a biphasic pattern, mainly pronounced in chitosan-treated roots. Since these metabolites increased or decreased until to 72 h after chitosan elicitation and then progressively returned to their original level, a transient effect of chitosan on primary metabolism can be suggested. In other words the SC2 scores mainly describe the time-dependent changes of the metabolite levels occurring in the chitosan-treated roots before and after 72 h.

Bottom Line: In response to the increase of biomass density over time, a decrease in the synthesis of isoleucine, valine, pyruvate, methylamine, etanolamine, trigonelline, glutamine and fatty acids, and an increase in the synthesis of phenolic compounds, such as xanthones, epicatechin, gallic, and shikimic acid were observed.Chitosan treatment associated to a slowdown of root biomass growth caused an increase in DMAPP and a decrease in stigmasterol, shikimic acid, and tryptophan levels.Most of the metabolic variations as well as the morpho-anatomical alterations occurred within 72 h from the elicitation, suggesting an early response of H. perforatum roots to chitosan elicitation.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Biology, "Sapienza" University of Rome Rome, Italy.

ABSTRACT
The responses of Hypericum perforatum root cultures to chitosan elicitation had been investigated through (1)H-NMR-based metabolomics associated with morpho-anatomical analyses. The root metabolome was influenced by two factors, i.e., time of culture (associated with biomass growth and related "overcrowding stress") and chitosan elicitation. ANOVA simultaneous component analysis (ASCA) modeling showed that these factors act independently. In response to the increase of biomass density over time, a decrease in the synthesis of isoleucine, valine, pyruvate, methylamine, etanolamine, trigonelline, glutamine and fatty acids, and an increase in the synthesis of phenolic compounds, such as xanthones, epicatechin, gallic, and shikimic acid were observed. Among the xanthones, brasilixanthone B has been identified for the first time in chitosan-elicited root cultures of H. perforatum. Chitosan treatment associated to a slowdown of root biomass growth caused an increase in DMAPP and a decrease in stigmasterol, shikimic acid, and tryptophan levels. The histological analysis of chitosan-treated roots revealed a marked swelling of the root apex, mainly due to the hypertrophy of the first two sub-epidermal cell layers. In addition, periclinal divisions in hypertrophic cortical cells, resulting in an increase of cortical layers, were frequently observed. Most of the metabolic variations as well as the morpho-anatomical alterations occurred within 72 h from the elicitation, suggesting an early response of H. perforatum roots to chitosan elicitation. The obtained results improve the knowledge of the root responses to biotic stress and provide useful information to optimize the biotechnological production of plant compounds of industrial interest.

No MeSH data available.


Related in: MedlinePlus