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Proteomic analysis of Citrus sinensis roots and leaves in response to long-term magnesium-deficiency.

Peng HY, Qi YP, Lee J, Yang LT, Guo P, Jiang HX, Chen LS - BMC Genomics (2015)

Bottom Line: Mg-deficiency had decreased levels of proteins [i.e. ribulose-1,5-bisphosphate carboxylase (Rubisco), rubisco activase, oxygen evolving enhancer protein 1, photosynthetic electron transfer-like protein, ferredoxin-NADP reductase (FNR), aldolase] involved in photosynthesis, thus decreasing leaf photosynthesis.Our results demonstrated that proteomics were more affected by long-term Mg-deficiency in leaves than in roots, and that the adaptive responses differed between roots and leaves when exposed to long-term Mg-deficiency.Mg-deficiency decreased the levels of many proteins involved in photosynthesis, thus decreasing leaf photosynthesis.

View Article: PubMed Central - PubMed

Affiliation: College of Resource and Environmental Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. 263618957@qq.com.

ABSTRACT

Background: Magnesium (Mg)-deficiency is frequently observed in Citrus plantations and is responsible for the loss of productivity and poor fruit quality. Knowledge on the effects of Mg-deficiency on upstream targets is scarce. Seedlings of 'Xuegan' [Citrus sinensis (L.) Osbeck] were irrigated with Mg-deficient (0 mM MgSO4) or Mg-sufficient (1 mM MgSO4) nutrient solution for 16 weeks. Thereafter, we first investigated the proteomic responses of C. sinensis roots and leaves to Mg-deficiency using two-dimensional electrophoresis (2-DE) in order to (a) enrich our understanding of the molecular mechanisms of plants to deal with Mg-deficiency and (b) understand the molecular mechanisms by which Mg-deficiency lead to a decrease in photosynthesis.

Results: Fifty-nine upregulated and 31 downregulated protein spots were isolated in Mg-deficient leaves, while only 19 upregulated and 12 downregulated protein spots in Mg-deficient roots. Many Mg-deficiency-responsive proteins were involved in carbohydrate and energy metabolism, followed by protein metabolism, stress responses, nucleic acid metabolism, cell wall and cytoskeleton metabolism, lipid metabolism and cell transport. The larger changes in leaf proteome versus root one in response to Mg-deficiency was further supported by our observation that total soluble protein concentration was decreased by Mg-deficiency in leaves, but unaffected in roots. Mg-deficiency had decreased levels of proteins [i.e. ribulose-1,5-bisphosphate carboxylase (Rubisco), rubisco activase, oxygen evolving enhancer protein 1, photosynthetic electron transfer-like protein, ferredoxin-NADP reductase (FNR), aldolase] involved in photosynthesis, thus decreasing leaf photosynthesis. To cope with Mg-deficiency, C. sinensis leaves and roots might respond adaptively to Mg-deficiency through: improving leaf respiration and lowering root respiration, but increasing (decreasing) the levels of proteins related to ATP synthase in roots (leaves); enhancing the levels of proteins involved in reactive oxygen species (ROS) scavenging and other stress-responsive proteins; accelerating proteolytic cleavage of proteins by proteases, protein transport and amino acid metabolism; and upregulating the levels of proteins involved in cell wall and cytoskeleton metabolism.

Conclusions: Our results demonstrated that proteomics were more affected by long-term Mg-deficiency in leaves than in roots, and that the adaptive responses differed between roots and leaves when exposed to long-term Mg-deficiency. Mg-deficiency decreased the levels of many proteins involved in photosynthesis, thus decreasing leaf photosynthesis.

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The potential regulatory network of Mg-deficiency-induced responses inCitrusleaves (A) and roots (B). BPG-PGAM: 2,3-Bisphosphoglycerate-independent phosphoglycerate mutase 1; CVP2: Type I inositol-1,4,5-trisphosphate 5-phosphatase CVP2; DBA- RNA helicase: Dead box ATP-dependent RNA helicase; DLST: Dihydrolipoamide succinyltransferase component of 2-oxoglutarate dehydrogenase; DRP: Disease resistance protein; Fru: Fructose; Glu: Glucose; Gs: Stomatal conductance; LOS2: 2-Phospho-D-glycerate hydrolase; NADP-MDH: NADP-malate dehydrogenase; PCOGRP: Pollen coat oleosin-glycine rich protein; PDC: Pyruvate decarboxylase; PETLP: Photosynthetic electron transfer-like protein; Pn: Photosynthesis; Suc: Sucrose; Tim17/Tim22/Tim23: Mitochondrial import inner membrane translocase subunit Tim17/Tim22/Tim23 family protein.
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Fig9: The potential regulatory network of Mg-deficiency-induced responses inCitrusleaves (A) and roots (B). BPG-PGAM: 2,3-Bisphosphoglycerate-independent phosphoglycerate mutase 1; CVP2: Type I inositol-1,4,5-trisphosphate 5-phosphatase CVP2; DBA- RNA helicase: Dead box ATP-dependent RNA helicase; DLST: Dihydrolipoamide succinyltransferase component of 2-oxoglutarate dehydrogenase; DRP: Disease resistance protein; Fru: Fructose; Glu: Glucose; Gs: Stomatal conductance; LOS2: 2-Phospho-D-glycerate hydrolase; NADP-MDH: NADP-malate dehydrogenase; PCOGRP: Pollen coat oleosin-glycine rich protein; PDC: Pyruvate decarboxylase; PETLP: Photosynthetic electron transfer-like protein; Pn: Photosynthesis; Suc: Sucrose; Tim17/Tim22/Tim23: Mitochondrial import inner membrane translocase subunit Tim17/Tim22/Tim23 family protein.

Mentions: We first investigated the proteomic changes induced by long-term Mg-deficiency in C. sinensis leaves and roots using 2-DE. In Mg-deficient leaves, 59 upregulated and 31 downregulated proteins were isolated, while only 19 upregulated and 12 downregulated proteins in Mg-deficient roots. This indicated that proteomes were more affected by long-term Mg-deficiency in the leaves than in the roots, which was further supported by our observation that the concentration of total soluble proteins was decreased by Mg-deficiency in leaves, but unaffected in roots. A potential regulatory network of Mg-deficiency-induced responses in Citrus leaves and roots was proposed through the integration of the present results and available data in the literatures (Figure 9). Mg-deficiency led to decreased abundances of proteins (Rubisco, Rubisco activase, OEE1, photosynthetic electron transfer-like protein, FNR etc.) involved in photosyntheis, thus decreasing leaf CO2 assimilation. The adaptive responses of C. sinensis roots and leaves to Mg-deficiency might including several aspects: (a) improving leaf respiration and lowering root respiration, but increasing (decreasing) the levels of proteins related to ATP synthase in roots (leaves); (b) enhancing the levels of proteins (such as APX, Cu/Zn SOD, GST, AKR, NPDK and ADH) involved in ROS scavenging and other stress-responsive proteins (i.e. HSPs and stress-related proteins); (c) accelerating proteolytic cleavage of proteins by proteases, protein transport and amino acid metabolism; and (d) upregulating the levels of proteins involved in cell wall and cytoskeleton metabolism. Therefore, our proteomic analysis provides an integrated view of the adaptive responses occurring in Mg-deficient leaves and roots of C. sinensis. As a first attempt, the present study will be useful for further investigating the roles of Mg in higher plants. It is worth noting that it may provide more data on Mg-deficiency in real Citrus orchards if we use grafted plants rather than C. sinensis seedlings as experimental materials, but it is difficult for us to compare the present data with the transcriptomic data obtained on Arabidopsis roots and leaves [12,13] and the physiological and biochemical data obtained on C. sinensis roots and leaves [5,8]. In the further study, we will investigate the effects of rootstocks on Mg-deficiency-responsive proteomics using grafted citrus plants from different rootstock-scion combinations including both own-rooted scions and rootstocks as controls to obtain more knowledge on Mg-deficiency in real citrus orchards.Figure 9


Proteomic analysis of Citrus sinensis roots and leaves in response to long-term magnesium-deficiency.

Peng HY, Qi YP, Lee J, Yang LT, Guo P, Jiang HX, Chen LS - BMC Genomics (2015)

The potential regulatory network of Mg-deficiency-induced responses inCitrusleaves (A) and roots (B). BPG-PGAM: 2,3-Bisphosphoglycerate-independent phosphoglycerate mutase 1; CVP2: Type I inositol-1,4,5-trisphosphate 5-phosphatase CVP2; DBA- RNA helicase: Dead box ATP-dependent RNA helicase; DLST: Dihydrolipoamide succinyltransferase component of 2-oxoglutarate dehydrogenase; DRP: Disease resistance protein; Fru: Fructose; Glu: Glucose; Gs: Stomatal conductance; LOS2: 2-Phospho-D-glycerate hydrolase; NADP-MDH: NADP-malate dehydrogenase; PCOGRP: Pollen coat oleosin-glycine rich protein; PDC: Pyruvate decarboxylase; PETLP: Photosynthetic electron transfer-like protein; Pn: Photosynthesis; Suc: Sucrose; Tim17/Tim22/Tim23: Mitochondrial import inner membrane translocase subunit Tim17/Tim22/Tim23 family protein.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
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Fig9: The potential regulatory network of Mg-deficiency-induced responses inCitrusleaves (A) and roots (B). BPG-PGAM: 2,3-Bisphosphoglycerate-independent phosphoglycerate mutase 1; CVP2: Type I inositol-1,4,5-trisphosphate 5-phosphatase CVP2; DBA- RNA helicase: Dead box ATP-dependent RNA helicase; DLST: Dihydrolipoamide succinyltransferase component of 2-oxoglutarate dehydrogenase; DRP: Disease resistance protein; Fru: Fructose; Glu: Glucose; Gs: Stomatal conductance; LOS2: 2-Phospho-D-glycerate hydrolase; NADP-MDH: NADP-malate dehydrogenase; PCOGRP: Pollen coat oleosin-glycine rich protein; PDC: Pyruvate decarboxylase; PETLP: Photosynthetic electron transfer-like protein; Pn: Photosynthesis; Suc: Sucrose; Tim17/Tim22/Tim23: Mitochondrial import inner membrane translocase subunit Tim17/Tim22/Tim23 family protein.
Mentions: We first investigated the proteomic changes induced by long-term Mg-deficiency in C. sinensis leaves and roots using 2-DE. In Mg-deficient leaves, 59 upregulated and 31 downregulated proteins were isolated, while only 19 upregulated and 12 downregulated proteins in Mg-deficient roots. This indicated that proteomes were more affected by long-term Mg-deficiency in the leaves than in the roots, which was further supported by our observation that the concentration of total soluble proteins was decreased by Mg-deficiency in leaves, but unaffected in roots. A potential regulatory network of Mg-deficiency-induced responses in Citrus leaves and roots was proposed through the integration of the present results and available data in the literatures (Figure 9). Mg-deficiency led to decreased abundances of proteins (Rubisco, Rubisco activase, OEE1, photosynthetic electron transfer-like protein, FNR etc.) involved in photosyntheis, thus decreasing leaf CO2 assimilation. The adaptive responses of C. sinensis roots and leaves to Mg-deficiency might including several aspects: (a) improving leaf respiration and lowering root respiration, but increasing (decreasing) the levels of proteins related to ATP synthase in roots (leaves); (b) enhancing the levels of proteins (such as APX, Cu/Zn SOD, GST, AKR, NPDK and ADH) involved in ROS scavenging and other stress-responsive proteins (i.e. HSPs and stress-related proteins); (c) accelerating proteolytic cleavage of proteins by proteases, protein transport and amino acid metabolism; and (d) upregulating the levels of proteins involved in cell wall and cytoskeleton metabolism. Therefore, our proteomic analysis provides an integrated view of the adaptive responses occurring in Mg-deficient leaves and roots of C. sinensis. As a first attempt, the present study will be useful for further investigating the roles of Mg in higher plants. It is worth noting that it may provide more data on Mg-deficiency in real Citrus orchards if we use grafted plants rather than C. sinensis seedlings as experimental materials, but it is difficult for us to compare the present data with the transcriptomic data obtained on Arabidopsis roots and leaves [12,13] and the physiological and biochemical data obtained on C. sinensis roots and leaves [5,8]. In the further study, we will investigate the effects of rootstocks on Mg-deficiency-responsive proteomics using grafted citrus plants from different rootstock-scion combinations including both own-rooted scions and rootstocks as controls to obtain more knowledge on Mg-deficiency in real citrus orchards.Figure 9

Bottom Line: Mg-deficiency had decreased levels of proteins [i.e. ribulose-1,5-bisphosphate carboxylase (Rubisco), rubisco activase, oxygen evolving enhancer protein 1, photosynthetic electron transfer-like protein, ferredoxin-NADP reductase (FNR), aldolase] involved in photosynthesis, thus decreasing leaf photosynthesis.Our results demonstrated that proteomics were more affected by long-term Mg-deficiency in leaves than in roots, and that the adaptive responses differed between roots and leaves when exposed to long-term Mg-deficiency.Mg-deficiency decreased the levels of many proteins involved in photosynthesis, thus decreasing leaf photosynthesis.

View Article: PubMed Central - PubMed

Affiliation: College of Resource and Environmental Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. 263618957@qq.com.

ABSTRACT

Background: Magnesium (Mg)-deficiency is frequently observed in Citrus plantations and is responsible for the loss of productivity and poor fruit quality. Knowledge on the effects of Mg-deficiency on upstream targets is scarce. Seedlings of 'Xuegan' [Citrus sinensis (L.) Osbeck] were irrigated with Mg-deficient (0 mM MgSO4) or Mg-sufficient (1 mM MgSO4) nutrient solution for 16 weeks. Thereafter, we first investigated the proteomic responses of C. sinensis roots and leaves to Mg-deficiency using two-dimensional electrophoresis (2-DE) in order to (a) enrich our understanding of the molecular mechanisms of plants to deal with Mg-deficiency and (b) understand the molecular mechanisms by which Mg-deficiency lead to a decrease in photosynthesis.

Results: Fifty-nine upregulated and 31 downregulated protein spots were isolated in Mg-deficient leaves, while only 19 upregulated and 12 downregulated protein spots in Mg-deficient roots. Many Mg-deficiency-responsive proteins were involved in carbohydrate and energy metabolism, followed by protein metabolism, stress responses, nucleic acid metabolism, cell wall and cytoskeleton metabolism, lipid metabolism and cell transport. The larger changes in leaf proteome versus root one in response to Mg-deficiency was further supported by our observation that total soluble protein concentration was decreased by Mg-deficiency in leaves, but unaffected in roots. Mg-deficiency had decreased levels of proteins [i.e. ribulose-1,5-bisphosphate carboxylase (Rubisco), rubisco activase, oxygen evolving enhancer protein 1, photosynthetic electron transfer-like protein, ferredoxin-NADP reductase (FNR), aldolase] involved in photosynthesis, thus decreasing leaf photosynthesis. To cope with Mg-deficiency, C. sinensis leaves and roots might respond adaptively to Mg-deficiency through: improving leaf respiration and lowering root respiration, but increasing (decreasing) the levels of proteins related to ATP synthase in roots (leaves); enhancing the levels of proteins involved in reactive oxygen species (ROS) scavenging and other stress-responsive proteins; accelerating proteolytic cleavage of proteins by proteases, protein transport and amino acid metabolism; and upregulating the levels of proteins involved in cell wall and cytoskeleton metabolism.

Conclusions: Our results demonstrated that proteomics were more affected by long-term Mg-deficiency in leaves than in roots, and that the adaptive responses differed between roots and leaves when exposed to long-term Mg-deficiency. Mg-deficiency decreased the levels of many proteins involved in photosynthesis, thus decreasing leaf photosynthesis.

Show MeSH
Related in: MedlinePlus