The Endophytic Fungus Piriformospora Indica-Assisted Alleviation of Cadmium in Tobacco

Increasing evidence suggests that the endophytic fungus Piriformospora indica helps plants overcome various abiotic stresses, especially heavy metals. However, the mechanism of heavy metal tolerance has not yet been elucidated. Here, the role of P. indica in alleviating cadmium (Cd) toxicities in tobacco was investigated. It was found that P. indica improved Cd tolerance to tobacco, increasing Cd accumulation in roots but decreasing Cd accumulation in leaves. The colonization of P. indica altered the subcellular repartition of Cd, increasing the Cd proportion in cell walls while reducing the Cd proportion in membrane/organelle and soluble fractions. During Cd stress, P. indica significantly enhanced the peroxidase (POD) activity and glutathione (GSH) content in tobacco. The spatial distribution of GSH was further visualized by Raman spectroscopy, showing that GSH was distributed in the cortex of P. indica-inoculated roots while in the epidermis of the control roots. A LC-MS/MS-based label-free quantitative technique evaluated the differential proteomics of P. indica treatment vs. control plants under Cd stress. The expressions of peroxidase, glutathione synthase, and photosynthesis-related proteins were significantly upregulated. This study provided extensive evidence for how P. indica enhances Cd tolerance in tobacco at physiological, cytological, and protein levels.

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A MYB4-MAN3-Mannose-MNB1 signaling cascade regulates cadmium tolerance in arabidopsis

PLoS Genetics ◽

10.1371/journal.pgen.1009636 ◽

2021 ◽

Vol 17 (6) ◽

pp. e1009636

Author(s):

Xingxing Yan ◽

Ying Huang ◽

Hui Song ◽

Feng Chen ◽

Qingliu Geng ◽

...

Keyword(s):

Signaling Cascade ◽

Plant Responses ◽

Cadmium Tolerance ◽

Compelling Evidence ◽

Loss Of Function ◽

Cd Stress ◽

Cd Accumulation ◽

Cd Tolerance ◽

Mannose Binding ◽

Underlying Mechanisms

Our previous studies showed that MAN3-mediated mannose plays an important role in plant responses to cadmium (Cd) stress. However, the underlying mechanisms and signaling pathways involved are poorly understood. In this study, we showed that an Arabidopsis MYB4-MAN3-Mannose-MNB1 signaling cascade is involved in the regulation of plant Cd tolerance. Loss-of-function of MNB1 (mannose-binding-lectin 1) led to decreased Cd accumulation and tolerance, whereas overexpression of MNB1 significantly enhanced Cd accumulation and tolerance. Consistently, expression of the genes involved in the GSH-dependent phytochelatin (PC) synthesis pathway (such as GSH1, GSH2, PCS1, and PCS2) was significantly reduced in the mnb1 mutants but markedly increased in the MNB1-OE lines in the absence or presence of Cd stress, which was positively correlated with Cd-activated PC synthesis. Moreover, we found that mannose is able to bind to the GNA-related domain of MNB1, and that mannose binding to the GNA-related domain of MNB1 is required for MAN3-mediated Cd tolerance in Arabidopsis. Further analysis showed that MYB4 directly binds to the promoter of MAN3 to positively regulate the transcript of MAN3 and thus Cd tolerance via the GSH-dependent PC synthesis pathway. Consistent with these findings, overexpression of MAN3 rescued the Cd-sensitive phenotype of the myb4 mutant but not the mnb1 mutant, whereas overexpression of MNB1 rescued the Cd-sensitive phenotype of the myb4 mutant. Taken together, our results provide compelling evidence that a MYB4-MAN3-Mannose-MNB1 signaling cascade regulates cadmium tolerance in Arabidopsis through the GSH-dependent PC synthesis pathway.

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Heavy metal tolerance and accumulation of Triarrhena sacchariflora, a large amphibious ornamental grass

Water Science & Technology ◽

10.2166/wst.2013.424 ◽

2013 ◽

Vol 68 (8) ◽

pp. 1795-1800 ◽

Cited By ~ 5

Author(s):

R. N. Tian ◽

S. Yu ◽

S. G. Wang ◽

Y. Zhang ◽

J. Y. Tang ◽

...

Keyword(s):

Heavy Metal ◽

Metal Tolerance ◽

Heavy Metal Tolerance ◽

Dry Weight ◽

Cd Stress ◽

Bioconcentration Factors ◽

Uptake Efficiency ◽

Translocation Efficiency ◽

Hyperaccumulator Plant ◽

Accumulation Ability

In this study, we report the tolerance and accumulation of Triarrhena sacchariflora to copper (Cu) and cadmium (Cd). The results show that T. sacchariflora had strong tolerance to Cu and Cd stress. The tolerance indexes (TI) were greater than 0.5 for all treatments. The bioconcentration factors (BCFs) to Cu and Cd were both above 1.0. The accumulation ability of roots was stronger than that of shoots, and ranges of BCF to Cu and Cd in roots were 37.89–79.08 and 83.96–300.57, respectively. However, the translocation ability to Cu and Cd was weak, with more than 86% of Cu or Cd accumulated in roots, suggesting an exclusion strategy for heavy metal tolerance. The uptake efficiency (UE) and translocation efficiency (TE) to Cu and Cd increased linearly as the Cu and Cd concentration in the substrate increased. UE was higher than TE, with a maximum of 2,118.90 μg g−1 root dry weight (DW) (50 mg L−1 Cu) and 1,847.51 μg g−1 root DW (20 mg L−1Cd), respectively. The results indicate that T. sacchariflora is a Cu- and Cd-tolerant non-hyperaccumulator plant, suggesting that T. sacchariflora could play an important role in phytoremediation in areas contaminated with Cu and Cd.

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Differences in Cadmium Accumulation, Detoxification and Antioxidant Defenses between Contrasting Maize Cultivars Implicate a Role of Superoxide Dismutase in Cd Tolerance

Antioxidants ◽

10.3390/antiox10111812 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1812

Author(s):

Aya Mahmoud ◽

Hamada AbdElgawad ◽

Badreldin A. Hamed ◽

Gerrit T.S. Beemster ◽

Nadia M. El-Shafey

Keyword(s):

Superoxide Dismutase ◽

Antioxidant Defense ◽

Antioxidant Defense System ◽

Antioxidant Defenses ◽

Cd Stress ◽

Defense System ◽

Cd Accumulation ◽

Cd Tolerance ◽

Maize Cultivars

Cadmium (Cd), a readily absorbed and translocated toxic heavy metal, inhibits plant growth, interrupts metabolic homeostasis and induces oxidative damage. Responses towards Cd-stress differ among plant cultivars, and the complex integrated relationships between Cd accumulation, detoxification mechanisms and antioxidant defenses still need to be unraveled. To this end, 12 Egyptian maize cultivars were grown under Cd-stress to test their Cd-stress tolerance. Out of these cultivars, tolerant (TWC360 and TWC321), moderately sensitive (TWC324) and sensitive (SC128) cultivars were selected, and we determined their response to Cd in terms of biomass, Cd accumulation and antioxidant defense system. The reduction in biomass was highly obvious in sensitive cultivars, while TWC360 and TWC321 showed high Cd-tolerance. The cultivar TWC321 showed lower Cd uptake concurrently with an enhanced antioxidant defense system. Interestingly, TWC360 accumulated more Cd in the shoot, accompanied with increased Cd detoxification and sequestration. A principal component analysis revealed a clear separation between the sensitive and tolerant cultivars with significance of the antioxidant defenses, including superoxide dismutase (SOD). To confirm the involvement of SOD in Cd-tolerance, we studied the effect of Cd-stress on a transgenic maize line (TG) constitutively overexpressing AtFeSOD gene in comparison to its wild type (WT). Compared to their WT, the TG plants showed less Cd accumulation and improved growth, physiology, antioxidant and detoxification systems. These results demonstrate the role of SOD in determining Cd-tolerance.

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Faculty Opinions recommendation of The endophytic fungus Piriformospora indica reprograms barley to salt-stress tolerance, disease resistance, and higher yield.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1028094.335010 ◽

2005 ◽

Author(s):

Simon McQueen-Mason

Keyword(s):

Salt Stress ◽

Disease Resistance ◽

Stress Tolerance ◽

Endophytic Fungus ◽

Piriformospora Indica ◽

Salt Stress Tolerance

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Heavy Metal Tolerance Trend in Extended-Spectrum β-Lactamase Encoding Strains Recovered from Food Samples

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094718 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4718

Author(s):

Kashaf Junaid ◽

Hasan Ejaz ◽

Iram Asim ◽

Sonia Younas ◽

Humaira Yasmeen ◽

...

Keyword(s):

Heavy Metal ◽

Metal Tolerance ◽

Heavy Metal Tolerance ◽

Heavy Metal Resistance ◽

Metal Resistance ◽

Food Samples ◽

Esbl Production ◽

Extended Spectrum ◽

Retail Food ◽

Esbl Producers

This study evaluates bacteriological profiles in ready-to-eat (RTE) foods and assesses antibiotic resistance, extended-spectrum β-lactamase (ESBL) production by gram-negative bacteria, and heavy metal tolerance. In total, 436 retail food samples were collected and cultured. The isolates were screened for ESBL production and molecular detection of ESBL-encoding genes. Furthermore, all isolates were evaluated for heavy metal tolerance. From 352 culture-positive samples, 406 g-negative bacteria were identified. Raw food samples were more often contaminated than refined food (84.71% vs. 76.32%). The predominant isolates were Klebsiella pneumoniae (n = 76), Enterobacter cloacae (n = 58), and Escherichia coli (n = 56). Overall, the percentage of ESBL producers was higher in raw food samples, although higher occurrences of ESBL-producing E. coli (p = 0.01) and Pseudomonas aeruginosa (p = 0.02) were observed in processed food samples. However, the prevalence of ESBL-producing Citrobacter freundii in raw food samples was high (p = 0.03). Among the isolates, 55% were blaCTX-M, 26% were blaSHV, and 19% were blaTEM. Notably, heavy metal resistance was highly prevalent in ESBL producers. These findings demonstrate that retail food samples are exposed to contaminants including antibiotics and heavy metals, endangering consumers.

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Growth and Antioxidant Responses in Iron-Biofortified Lentil under Cadmium Stress

Toxics ◽

10.3390/toxics9080182 ◽

2021 ◽

Vol 9 (8) ◽

pp. 182

Author(s):

Ruchi Bansal ◽

Swati Priya ◽

Harsh Kumar Dikshit ◽

Sherry Rachel Jacob ◽

Mahesh Rao ◽

...

Keyword(s):

Growth Parameters ◽

Dry Weight ◽

Cadmium Stress ◽

Antioxidant Enzyme Activities ◽

Limited Information ◽

Cd Stress ◽

Fresh Weight ◽

Cd Uptake ◽

Cd Tolerance ◽

Controlled Conditions

Cadmium (Cd) is a hazardous heavy metal, toxic to our ecosystem even at low concentrations. Cd stress negatively affects plant growth and development by triggering oxidative stress. Limited information is available on the role of iron (Fe) in ameliorating Cd stress tolerance in legumes. This study assessed the effect of Cd stress in two lentil (Lens culinaris Medik.) varieties differing in seed Fe concentration (L4717 (Fe-biofortified) and JL3) under controlled conditions. Six biochemical traits, five growth parameters, and Cd uptake were recorded at the seedling stage (21 days after sowing) in the studied genotypes grown under controlled conditions at two levels (100 μM and 200 μM) of cadmium chloride (CdCl2). The studied traits revealed significant genotype, treatment, and genotype × treatment interactions. Cd-induced oxidative damage led to the accumulation of hydrogen peroxide (H2O2) and malondialdehyde in both genotypes. JL3 accumulated 77.1% more H2O2 and 75% more lipid peroxidation products than L4717 at the high Cd level. Antioxidant enzyme activities increased in response to Cd stress, with significant genotype, treatment, and genotype × treatment interactions (p < 0.01). L4717 had remarkably higher catalase (40.5%), peroxidase (43.9%), superoxide dismutase (31.7%), and glutathione reductase (47.3%) activities than JL3 under high Cd conditions. In addition, L4717 sustained better growth in terms of fresh weight and dry weight than JL3 under stress. JL3 exhibited high Cd uptake (14.87 mg g−1 fresh weight) compared to L4717 (7.32 mg g−1 fresh weight). The study concluded that the Fe-biofortified lentil genotype L4717 exhibited Cd tolerance by inciting an efficient antioxidative response to Cd toxicity. Further studies are required to elucidate the possibility of seed Fe content as a surrogacy trait for Cd tolerance.

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