Mitochondrial enzymes and citrate transporter contribute to the aluminium-induced citrate secretion from soybean (Glycine max) roots

2010 ◽  
Vol 37 (4) ◽  
pp. 285 ◽  
Author(s):  
Muyun Xu ◽  
Jiangfeng You ◽  
Ningning Hou ◽  
Hongmei Zhang ◽  
Guang Chen ◽  
...  

The concentration of soluble aluminium (Al) in the soil solution increases at low pH and the prevalence of toxic Al3+ cations represent the main factor limiting plant growth on acid soils. Citrate secretion from roots is an important Al-tolerance mechanism in many species including soybean. We isolated mitochondria from the roots of an Al-resistant soybean (Glycine max L.) cv. Jiyu 70 to investigate the relationship between citrate metabolism and Al-induced citrate secretion. Spectrophotometric assays revealed that the activities of mitochondrial malate dehydrogenase and citrate synthase increased and aconitase decreased with increasing of Al concentration (0–50 µM) and duration of Al treatment (30 µM Al, 0.5–9 h). Al-induced citrate secretion was inhibited by the citrate synthase inhibitor suramin, and enhanced by the aconitase inhibitor fluorocitric acid. Mersalyl acid, an inhibitor of a citrate carrier located in mitochondria membrane, also suppressed Al-induced citrate secretion. Transcript level of the mitochondrial citrate synthase gene increased in soybean roots exposed to Al, whereas expression of aconitase showed no significant difference. Expression of Gm-AlCT, a gene showing homology to Al-activated citrate transporters was also induced after 4 h in Al treatment. The Al-dependent changes in activity and expression of these enzymes are consistent with them supporting the sustained release of citrate from soybean roots.

2010 ◽  
Vol 37 (5) ◽  
pp. 478 ◽  
Author(s):  
Muyun Xu ◽  
Jiangfeng You ◽  
Ningning Hou ◽  
Hongmei Zhang ◽  
Guang Chen ◽  
...  

The concentration of soluble aluminium (Al) in the soil solution increases at low pH and the prevalence of toxic Al3+ cations represent the main factor limiting plant growth on acid soils. Citrate secretion from roots is an important Al-tolerance mechanism in many species including soybean. We isolated mitochondria from the roots of an Al-resistant soybean (Glycine max L.) cv. Jiyu 70 to investigate the relationship between citrate metabolism and Al-induced citrate secretion. Spectrophotometric assays revealed that the activities of mitochondrial malate dehydrogenase and citrate synthase increased and aconitase decreased with increasing of Al concentration (0–50 µM) and duration of Al treatment (30 µM Al, 0.5–9 h). Al-induced citrate secretion was inhibited by the citrate synthase inhibitor suramin, and enhanced by the aconitase inhibitor fluorocitric acid. Mersalyl acid, an inhibitor of a citrate carrier located in mitochondria membrane, also suppressed Al-induced citrate secretion. Transcript level of the mitochondrial citrate synthase gene increased in soybean roots exposed to Al, whereas expression of aconitase showed no significant difference. Expression of Gm-AlCT, a gene showing homology to Al-activated citrate transporters was also induced after 4 h in Al treatment. The Al-dependent changes in activity and expression of these enzymes are consistent with them supporting the sustained release of citrate from soybean roots.


2010 ◽  
Vol 37 (4) ◽  
pp. 296 ◽  
Author(s):  
Kengo Yokosho ◽  
Naoki Yamaji ◽  
Jian Feng Ma

Multidrug and toxic compound extrusion (MATE) proteins are widely present in bacteria, fungi, plants and mammals. Recent studies have showed that a group of plant MATE genes encodes citrate transporter, which are involved in the detoxification of aluminium or translocation of iron from the roots to the shoots. In this study, we isolated two homologous genes (ScFRDL1 and ScFRDL2) from this family in rye (Secale cereale L.). ScFRDL1 shared 94.2% identity with HvAACT1, an Al-activated citrate transporter in barley (Hordeum vulgare L.) and ScFRDL2 shared 80.6% identity with OsFRDL2, a putative Al-responsive protein in rice (Oryza sativa L.). Both genes were mainly expressed in the roots, however, they showed different expression patterns. Expression of ScFRDL1 was unaffected by Al treatment, but up-regulated by Fe-deficiency treatment. In contrast, expression of ScFRDL2 was greatly induced by Al but not by Fe deficiency. The Al-induced up-regulation of ScFRDL2 was found in both the root tips and basal roots. Furthermore, the expression pattern of ScFRDL2 was consistent with citrate secretion pattern. Immunostaining showed that ScFRDL1 was localised at all cells in the root tips and central cylinder and endodermis in the basal root. Taken together, our results suggest that ScFRDL1 was involved in efflux of citrate into the xylem for Fe translocation from the roots to the shoots, while ScFRDL2 was involved in Al-activated citrate secretion in rye.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wannian Li ◽  
Patrick M. Finnegan ◽  
Qin Dai ◽  
Dongqiang Guo ◽  
Mei Yang

Abstract Background Eucalyptus is the main plantation wood species, mostly grown in aluminized acid soils. To understand the response of Eucalyptus clones to aluminum (Al) toxicity, the Al-tolerant Eucalyptus grandis × E. urophylla clone GL-9 (designated “G9”) and the Al-sensitive E. urophylla clone GL-4 (designated “W4”) were employed to investigate the production and secretion of citrate and malate by roots. Results Eucalyptus seedlings in hydroponics were exposed to the presence or absence of 4.4 mM Al at pH 4.0 for 24 h. The protein synthesis inhibitor cycloheximide (CHM) and anion channel blocker phenylglyoxal (PG) were applied to explore possible pathways involved in organic acid secretion. The secretion of malate and citrate was earlier and greater in G9 than in W4, corresponding to less Al accumulation in G9. The concentration of Al in G9 roots peaked after 1 h and decreased afterwards, corresponding with a rapid induction of malate secretion. A time-lag of about 6 h in citrate efflux in G9 was followed by robust secretion to support continuous Al-detoxification. Malate secretion alone may alleviate Al toxicity because the peaks of Al accumulation and malate secretion were simultaneous in W4, which did not secrete appreciable citrate. Enhanced activities of citrate synthase (CS) and phosphoenolpyruvate carboxylase (PEPC), and reduced activities of isocitrate dehydrogenase (IDH), aconitase (ACO) and malic enzyme (ME) were closely associated with the greater secretion of citrate in G9. PG effectively inhibited citrate and malate secretion in both Eucalyptus clones. CHM also inhibited malate and citrate secretion in G9, and citrate secretion in W4, but notably did not affect malate secretion in W4. Conclusions G9 immediately secrete malate from roots, which had an initial effect on Al-detoxification, followed by time-delayed citrate secretion. Pre-existing anion channel protein first contributed to malate secretion, while synthesis of carrier protein appeared to be needed for citrate excretion. The changes of organic acid concentrations in response to Al can be achieved by enhanced CS and PEPC activities, but was supported by changes in the activities of other enzymes involved in organic acid metabolism. The above information may help to further explore genes related to Al-tolerance in Eucalyptus.


2020 ◽  
Author(s):  
Wannian Li ◽  
Patrick M. Finnegan ◽  
Qin Dai ◽  
Dongqiang Guo ◽  
Mei Yang

Abstract Background: Eucalyptus is the main plantation wood species, mostly grown in aluminized acid soils. To understand the response of Eucalyptus clones to aluminum (Al) toxicity, the Al-tolerant Eucalyptus grandis × E. urophylla clone GL-9 (designated “G9”) and the Al-sensitive E. urophylla clone GL-4 (designated “W4”) were employed to investigate the production and secretion of citrate and malate by roots.Results: Eucalyptus seedlings in hydroponics were exposed to the presence or absence of 4.4 mM Al at pH 4.0 for 24 hours. The protein synthesis inhibitor cycloheximide (CHM) and anion channel blocker phenylglyoxal (PG) were applied to explore possible pathways involved in organic acid secretion. The secretion of malate and citrate was earlier and greater in G9 than in W4, corresponding to less Al accumulation in G9. The concentration of Al in G9 roots peaked after 1h and decreased afterwards, corresponding with a rapid induction of malate secretion. A time-lag of about 6h in citrate efflux in G9 was followed by robust secretion to support continuous Al-detoxification. Malate secretion alone may alleviate Al toxicity because the peaks of Al accumulation and malate secretion were simultaneous in W4, which did not secrete appreciable citrate. Enhanced activities of citrate synthase (CS) and phosphoenolpyruvate carboxylase (PEPC), and reduced activities of isocitrate dehydrogenase (IDH), aconitase (ACO) and malic enzyme (ME) were closely associated with the greater secretion of citrate in G9. PG effectively inhibited citrate and malate secretion in both Eucalyptus clones. CHM also inhibited malate and citrate secretion in G9, and citrate secretion in W4, but notably did not affect malate secretion in W4. Conclusions: G9 immediately secrete malate from roots, which had an initial effect on Al-detoxification, followed by time-delayed citrate secretion. Pre-existing anion channel protein first contributed to malate secretion, while synthesis of carrier protein appeared to be needed for citrate excretion. The changes of organic acid concentrations in response to Al can be achieved by enhanced CS and PEPC activities, but was supported by changes in the activities of other enzymes involved in organic acid metabolism. The above information may help to further explore genes related to Al-tolerance in Eucalyptus.


2020 ◽  
Author(s):  
Wannian Li ◽  
Patrick Finnegan ◽  
Qin Dai ◽  
Dongqiang Guo ◽  
Mei Yang

Abstract Background: Eucalyptus is the main plantation wood species, mostly grown in aluminized acid soils. To understand the response of Eucalyptus clones to aluminum (Al) toxicity, the Al-tolerant Eucalyptus grandis × E. urophylla clone GL-9 (designated “G9”) and the Al-sensitive E. urophylla clone GL-4 (designated “W4”) were employed to investigate the production and secretion of citrate and malate by roots.Results: Eucalyptus seedlings in hydroponics were exposed to the presence or absence of 4.4 mM Al at pH 4.0 for 24 hours. The protein synthesis inhibitor cycloheximide (CHM) and anion channel blocker phenylglyoxal (PG) were applied to explore possible pathways involved in organic acid secretion. The secretion of malate and citrate was earlier and greater in G9 than in W4, corresponding to less Al accumulation in G9. The concentration of Al in G9 roots peaked after 1h and decreased afterwards, corresponding with a rapid induction of malate secretion. A time-lag of about 6h in citrate efflux in G9 was followed by robust secretion to support continuous Al-detoxification. Malate secretion alone may alleviate Al toxicity because the peaks of Al accumulation and malate secretion were simultaneous in W4, which did not secrete appreciable citrate. Enhanced activities of citrate synthase (CS) and phosphoenolpyruvate carboxylase (PEPC), and reduced activities of isocitrate dehydrogenase (IDH), aconitase (ACO) and malic enzyme (ME) were closely associated with the greater secretion of citrate in G9. PG effectively inhibited citrate and malate secretion in both Eucalyptus clones. CHM also inhibited malate and citrate secretion in G9, and citrate secretion in W4, but notably did not affect malate secretion in W4.Conclusions: G9 immediately secrete malate from roots, which had an initial effect on Al-detoxification, followed by time-delayed citrate secretion. Pre-existing anion channel protein first contributed to malate secretion, while synthesis of carrier protein appeared to be needed for citrate excretion. The changes of organic acid concentrations in response to Al can be achieved by enhanced CS and PEPC activities, but was supported by changes in the activities of other enzymes involved in organic acid metabolism. The above information may help to further explore genes related to Al-tolerance in Eucalyptus.


2021 ◽  
Vol 15 (2) ◽  
pp. 156-162
Author(s):  
Tao Lin ◽  
Rongrong Han ◽  
Yunmin Wei ◽  
Lusheng Liu ◽  
Caode Jiang ◽  
...  

The aluminum tolerance of Tamba black soybean (Glycine max cv. Tamba) is closely related to organic acid secretion mechanisms. The gene responsible for this tolerance in this variety (GmFER84) is extracted from lysates of soybean root tips using silylated Fe3O4 nanomagnetic beads. GmFER84 (Glycine max XP 003540203.1) is a stable protein. Tobacco genetically transformed with GmFER84 using an Agrobacterium-mediated transformation was tested for aluminum tolerance. Citrate synthase and citric acid secretion in the roots of transgenic tobacco prove to be significantly higher than those of wild tobacco, and the antioxidant properties of transgenic tobacco are also substantially increased. Research on GmFER84 may enable further agronomic development.


2018 ◽  
Vol 435 (1-2) ◽  
pp. 127-142 ◽  
Author(s):  
Huahua Wang ◽  
Yangyang Zhang ◽  
Junjie Hou ◽  
Wenwen Liu ◽  
Junjun Huang ◽  
...  

1995 ◽  
Vol 269 (1) ◽  
pp. R64-R72 ◽  
Author(s):  
C. M. Bishop ◽  
P. J. Butler ◽  
S. Egginton ◽  
A. J. el Haj ◽  
G. W. Gabrielsen

Preflight development of the goslings was typified by rapid increases in the mitochondrial enzymes of the semimembranosus and heart ventricular muscles resulting in near-adult values by 3 wk of age. In contrast, aerobic capacity of the pectoralis muscle initially developed slowly but showed a rapid increase between 5 and 7 wk of age, in preparation for becoming airborne. Activities of glycolytic enzymes in the pectoralis muscle showed similar patterns of development as those found for the aerobic enzymes, except for hexokinase, which was low at all ages, indicating an adaptation for catabolism of both intracellular glycogen and plasma fatty acids in preference to plasma glucose. Muscle mass specific activity of citrate synthase in the pectoralis increased by only 33% from goslings during the first few days of flight, compared with premigratory geese. Activities of anaerobic glycolytic enzymes in the ventricles were low, but values for hexokinase, which is involved in the phosphorylation of plasma glucose, developed rapidly. Values for lactate dehydrogenase were also high, reflecting the capacity of the heart to catabolize plasma lactate. Substrate flux supplied by carnitine palmitoyltransferase and oxoglutarate dehydrogenase (OGD), in the pectoralis muscles of the premigratory geese, appears to have the smallest excess capacities to meet the requirements of sustained aerobic flight. The average maximum oxygen uptake for premigratory geese during flight, as indicated by values for OGD, is calculated to be 484 ml O2/min (or 208 ml O2.min-1.kg-1).


Author(s):  
Xia Zhang ◽  
Brayden Weir ◽  
Hongru Wei ◽  
Zhiwei Deng ◽  
Xiaoqi Zhang ◽  
...  

AbstractChickpea is an economically important legume crop with high nutritional value in human diets. Aluminium-toxicity poses a significant challenge for the yield improvement of this increasingly popular crop in acidic soils. The wild progenitors of chickpea may provide a more diverse gene pool for Al-tolerance in chickpea breeding. However, the genetic basis of Al-tolerance in chickpea and its wild relatives remains largely unknown. Here, we assessed the Al-tolerance of six selected wild Cicer accessions by measuring the root elongation in solution culture under control (0 µM Al3+) and Al-treatment (30 µM Al3+) conditions. Al-treatment significantly reduced the root elongation in all target lines compared to the control condition after 2-day’s growth. However, the relative reduction of root elongation in different lines varied greatly: 3 lines still retained significant root growth under Al-treatment, whilst another 2 lines displayed no root growth at all. We performed genome-wide identification of multidrug and toxic compound extrusion (MATE) encoding genes in the Cicer genome. A total of 56 annotated MATE genes were identified, which divided into 4 major phylogeny groups (G1-4). Four homologues to lupin LaMATE (> 50% aa identity; named CaMATE1-4) were clustered with previously characterised MATEs related to Al-tolerance in various other plants. qRT-PCR showed that CaMATE2 transcription in root tips was significantly up-regulated upon Al-treatment in all target lines, whilst CaMATE1 was up-regulated in all lines except Bari2_074 and Deste_064, which coincided with the lines displaying no root growth under Al-treatment. Transcriptional profiling in five Cicer tissues revealed that CaMATE1 is specifically transcribed in the root tissue, further supporting its role in Al-detoxification in roots. This first identification of MATE-encoding genes associated with Al-tolerance in Cicer paves the ways for future functional characterization of MATE genes in Cicer spp., and to facilitate future design of gene-specific markers for Al-tolerant line selection in chickpea breeding programs.


1993 ◽  
Vol 41 (5) ◽  
pp. 541 ◽  
Author(s):  
LM Egerton-Warbuton ◽  
BJ Griffin ◽  
BB Lamont

Selection for aluminium (Al) tolerance was assessed by studying pollen-pistil interactions in Eucalyptus calophylla trees colonising a 30-year-old abandoned coal mine-site (soil pH 4.3) compared with E. calophylla trees on an adjacent forest-site (soil pH 5.3). Energy-dispersive X-ray micro-analysis of reproductive tissues demonstrated that low levels of Al occurred in the stigma, lower style and unfertilised ovules of forest-site flowers. In contrast, significantly higher levels of Al were detected in all reproductive tissues of mine-site flowers. Al concentrations were higher at the base of the style than in the stigma. Al was also detected in stigmatic exudates of mine-site flowers. Selection for Al tolerance occurred in the anther of mine-site flowers as pollen from mine-site flowers germinated six-fold (15.6%) compared with forest-site pollen (2.6%) at the highest concentration of Al (22 ppm) used. However, the rate of pollen tube growth was not significantly different between mine- and forest-sites at any Al concentration. Tolerance of Al by the mine-site pollen was not shared by the progeny as there was no increase in the survival or growth of mine-site seedlings in mine soils over forest-site seedlings. Controlled pollinations between mine-/forest-site pollen and mine-site pistils demonstrated that there was no significant difference in the number of mine- or forest-site pollen tubes at any level in the style in mine-site pistils. Pollen tube abnormalities principally occurred in mine-site pistils. We concluded that there is no evidence yet for a genetically-based tolerance of Al in E. calophylla on coal mining soils.


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