copper tolerance
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2022 ◽  
Vol 231 ◽  
pp. 113197
Author(s):  
Junjie He ◽  
Pengfei Cheng ◽  
Jun Wang ◽  
Sheng Xu ◽  
Jianxin Zou ◽  
...  

Plant Disease ◽  
2021 ◽  
Author(s):  
Brodie Cox ◽  
Hehe Wang ◽  
Guido Schnabel

Bacterial spot of peach, caused by Xanthomonas arboricola pv. pruni (Xap), causes yield loss every year in southeastern United States peach orchards. Management is mainly driven by season-long applications of copper-based products, site location, and choice of cultivar. Although tolerance to copper has not been reported in Xap in the United States, adaptation of populations due to frequent use is a concern. We collected Xap from shoot cankers, leaves, and fruit of cv. O'Henry over two years from three conventional farms and one organic farm in South Carolina, one orchard per farm. The four farms had been using copper extensively for years to control bacterial spot. Xap was isolated from four canker types (bud canker, tip canker, non-concentric canker, and concentric canker) in early spring (‘bud break’), as well as from leaf and fruit tissues later in the season at phenological stages ‘pit hardening’ and ‘final swell’. Xap was most frequently isolated from cankers of the organic farm (24% of the cankers) and most isolates (45%) came from bud cankers. Xap isolates were assessed for sensitivity to copper using minimal glucose yeast agar and nutrient agar amended with 38 µg/ml or 51 µg/ml of Cu2+. Two phenotypes of copper-tolerance in Xap were discovered: low copper tolerance (LCT: growth up to 38 µg/ml Cu2+) and high copper tolerance (HCT: growth up to 51 µg/ml Cu2+). A total of 26 (23 LCT and 3 HCT) out of 165 isolates in 2018 and 32 (20 LCT and 12 HCT) out of 133 isolates in 2019 were tolerant to copper. Peach leaves on potted trees were sprayed with copper rates typically applied at ‘delayed dormancy’ (high rate; 2,397 µg/ml Cu2+), at ‘shuck split’ (medium rate; 599 µg/ml Cu2+), and during ‘summer cover sprays’ (low rate; 120 µg/ml Cu2+) and subsequently inoculated with sensitive, LCT and HCT strains. Results indicated that the low and medium rates of copper reduced bacterial spot incidence caused by the sensitive strain but not by the LCT and HCT strains. This study confirms existence of Xap tolerance to copper in commercial peach orchards in the southeastern United States and suggests its contribution to bacterial spot development under current management practices.


Metallomics ◽  
2021 ◽  
Author(s):  
Natalie Gugala ◽  
Daniel A Salazar-Alemán ◽  
Gordon Chua ◽  
Raymond J Turner

Abstract The competitive toxic and stress inducing nature of copper necessitates systems that sequester and export this metal from the cytoplasm of bacterial cells. Several predicted mechanisms of toxicity include the production of reactive oxygen species, thiol depletion, DNA and iron-sulfur cluster disruption. Accompanying these mechanisms include pathways of homeostasis such as chelation, oxidation, and transport. Still, the mechanisms of copper resistance and sensitivity are not fully understood. Furthermore, studies fail to recognize that the response to copper is likely a result of numerous mechanisms, as in the case for homeostasis, in which proteins and enzymes work as a collective to maintain appropriate copper concentrations. In this study we used the Keio collection, an array of 3985 Escherichia coli mutants, each with a deleted non-essential gene, to gain a better understanding of prolonged copper exposure. In short, we recovered two copper homeostatic gene and genes involved in transporting and assembling to be involved in mediating prolonged copper stress under the conditions assessed. The gene coding for the protein TolC was uncovered as a sensitive hit and we demonstrated that tolC, an outer membrane efflux channel, is key in mitigating copper sensitivity. Additionally, the activity of tRNA processing was enriched and the deletion of several proteins involved in import generated copper tolerance. Lastly, key genes belonging to central carbon metabolism and nicotinamide adenine dinucleotide biosynthesis were uncovered as tolerant hits. Overall, this study shows that copper sensitivity and tolerance are a result of numerous mechanisms acting in combination within the cell.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ru Bu ◽  
Bing Yan ◽  
Huijie Sun ◽  
Mengcheng Zhou ◽  
Huashan Bai ◽  
...  

Various agricultural products used in food fermentation are polluted by heavy metals, especially copper, which seriously endangers human health. Methods to remove copper with microbial strategies have gained interests. A novel Meyerozyma guilliermondii GXDK6 could survive independently under high stress of copper (1400 ppm). The copper tolerance mechanism of GXDK6 was revealed by integrated omics in this work. Whole-genome analysis showed that nine genes (i.e., CCC2, CTR3, FRE2, GGT, GST, CAT, SOD2, PXMP4, and HSP82) were related to GXDK6 copper tolerance. Copper stress elevated glutathione metabolism-related gene expression, glutathione content, and glutathione sulfur transferase activity, suggesting enhanced copper conjugation and detoxification in cells. The inhibited copper uptake by Ctr3 and enhanced copper efflux by Ccc2 contributed to the decrease in intracellular copper concentration. The improved expression of antioxidant enzyme genes (PXMP4, SOD2, and CAT), accompanied by the enhanced activities of antioxidant enzymes (peroxidase, superoxide dismutase, and catalase), decreased copper-induced reactive oxygen species production, protein carbonylation, lipid peroxidation, and cell death. The metabolite D-mannose against harsh stress conditions was beneficial to improving copper tolerance. This study contributed to understanding the copper tolerance mechanism of M. guilliermondii and its application in removing copper during fermentation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Isis Gabriela Barbosa Carvalho ◽  
Marcus Vinicius Merfa ◽  
Natália Sousa Teixeira-Silva ◽  
Paula Maria Moreira Martins ◽  
Marco Aurélio Takita ◽  
...  

Copper-based compounds are widely used in agriculture as a chemical strategy to limit the spread of multiple plant diseases; however, the continuous use of this heavy metal has caused environmental damage as well as the development of copper-resistant strains. Thus, it is important to understand how the bacterial phytopathogens evolve to manage with this metal in the field. The MqsRA Toxin–Antitoxin system has been recently described for its function in biofilm formation and copper tolerance in Xylella fastidiosa, a plant-pathogen bacterium responsible for economic damage in several crops worldwide. Here we identified differentially regulated genes by X. fastidiosa MqsRA by assessing changes in global gene expression with and without copper. Results show that mqsR overexpression led to changes in the pattern of cell aggregation, culminating in a global phenotypic heterogeneity, indicative of persister cell formation. This phenotype was also observed in wild-type cells but only in the presence of copper. This suggests that MqsR regulates genes that alter cell behavior in order to prime them to respond to copper stress, which is supported by RNA-Seq analysis. To increase cellular tolerance, proteolysis and efflux pumps and regulator related to multidrug resistance are induced in the presence of copper, in an MqsR-independent response. In this study we show a network of genes modulated by MqsR that is associated with induction of persistence in X. fastidiosa. Persistence in plant-pathogenic bacteria is an important genetic tolerance mechanism still neglected for management of phytopathogens in agriculture, for which this work expands the current knowledge and opens new perspectives for studies aiming for a more efficient control in the field.


2021 ◽  
Vol 221 ◽  
pp. 112469
Author(s):  
Ge-Zi Li ◽  
Yong-Xing Zheng ◽  
Shi-Juan Chen ◽  
Jin Liu ◽  
Peng-Fei Wang ◽  
...  
Keyword(s):  

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 905
Author(s):  
Sebastián Sepúlveda ◽  
Carla Duarte-Nass ◽  
Mariella Rivas ◽  
Laura Azócar ◽  
Andrés Ramírez ◽  
...  

This research focused on the evaluation of the potential use of a soil-isolated bacteria, identified as Staphylococcus equorum, for microbial-induced calcite precipitation (MICP) and copper removal. Isolated bacteria were characterized considering growth rate, urease activity, calcium carbonate precipitation, copper tolerance as minimum inhibitory concentration (MIC) and copper precipitation. Results were compared with Sporosarcina pasteurii, which is considered a model bacteria strain for MICP processes. The results indicated that the S. equorum strain had lower urease activity, calcium removal capacity and copper tolerance than the S. pasteurii strain. However, the culture conditions tested in this study did not consider the halophilic feature of the S. equorum, which could make it a promising bacterial strain to be applied in process water from mining operations when seawater is used as process water. On the other hand, copper removal was insufficient when applying any of the bacteria strains evaluated, most likely due to the formation of a copper–ammonia complex. Thus, the implementation of S. equorum for copper removal needs to be further studied, considering the optimization of culture conditions, which may promote better performance when considering calcium, copper or other metals precipitation.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1663
Author(s):  
Antonios Chrysargyris ◽  
Rita Maggini ◽  
Luca Incrocci ◽  
Alberto Pardossi ◽  
Nikolaos Tzortzakis

Heavy metal contamination is a major health issue concerning the commercial production of medicinal and aromatic plants (MAPs) that are used for the extraction of bioactive molecules. Copper (Cu) is an anthropogenic contaminant that, at toxic levels, can accumulate in plant tissues, affecting plant growth and development. On the other hand, plant response to metal-induced stress may involve the synthesis and accumulation of beneficial secondary metabolites. In this study, hydroponically grown Pelargonium graveolens plants were exposed to different Cu concentrations in a nutrient solution (4, 25, 50, 100 μM) to evaluate the effects Cu toxicity on plant growth, mineral uptake and distribution in plants, some stress indicators, and the accumulation of bioactive secondary metabolites in leaf tissues. P. graveolens resulted in moderately tolerant Cu toxicity. At Cu concentrations up to 100 μM, biomass production was preserved and was accompanied by an increase in phenolics and antioxidant capacity. The metal contaminant was accumulated mainly in the roots. The leaf tissues of Cu-treated P. graveolens may be safely used for the extraction of bioactive molecules.


2021 ◽  
Vol 9 (8) ◽  
pp. 1689
Author(s):  
Li He ◽  
Yanzhen Ren ◽  
Weimin Zeng ◽  
Xueling Wu ◽  
Li Shen ◽  
...  

Metallophytes microbiota play a key role in plant growth and resistance to heavy metal stress. Comparing to the well-studied single or some specific plant growth-promoting (PGP) bacterial strains, our current understanding of the structural and functional variations of microbiome of metallophytes is still limited. Here, we systematically investigated the endophytic and rhizosphere bacterial community profiles of a metallophyte Commelina communis growing in different Cu-polluted soils by high-throughput sequencing technology. The results showed that the rhizosphere communities of C. communis exhibited a much higher level of diversity and richness than the endosphere communities. Meanwhile, shifts in the bacterial community composition were observed between the rhizosphere and endosphere of C. communis, indicating plant compartment was a strong driver for the divergence between rhizosphere and endosphere community. Among the environmental factors, soil Cu content, followed by OM, TP and TN, played major roles in shaping the bacterial community structure of C. communis. At the highly Cu-contaminated site, Pseudomonas and Sphingomonas were the predominant genera in the endophytic and rhizospheric bacterial communities, respectively, which might enhance copper tolerance as PGP bacteria. In summary, our findings will be useful to better understand metallophyte–microbe interactions and select suitable bacterial taxa when facilitating phytoremediation.


2021 ◽  
Author(s):  
Llewellyn Green ◽  
Santiago E Radio ◽  
Gabriel Rech ◽  
Judit Salces-Ortiz ◽  
Josefa Gonzalez

Increases in industrialisation and anthropogenic activity have resulted in an increase in pollutants released into the environment. Of these pollutants, heavy metals such as copper are particularly concerning due to their bio-accumulative nature. Due to its highly heterogeneous distribution and its dual nature as both an essential micronutrient and toxic element, the genetic basis of copper tolerance is likely shaped by a complex interplay of physiological and environmental factors. Drosophila melanogaster, a long-standing sentinel of environmental toxins, is uniquely suited for the study of copper tolerance in arthropods and other more diverse species. In this study, we utilized the natural variation present in multiple populations of D. melanogaster collected across Europe to screen for variation in copper tolerance, which we found to be highly variable both within and between locations. While these collection locations covered a wide range of atmospheric and soil pollution levels, the degree of urbanization at the collection sites, rather than any other combination of environmental factors, was linked to copper tolerance. Moreover, differential expression analysis revealed that metabolism, reproduction, and protease induction contribute to copper response in tolerant and sensitive lines to different degrees. Additionally, the greatest transcriptomic and physiological responses to copper toxicity were seen in the midgut; where preservation of gut acidity is strongly linked to greater tolerance. Overall, our study provides a unique perspective on the genetic and environmental factors that shape copper tolerance in natural D. melanogaster populations and identifies new genes and physiological traits involved in this complex phenotype.


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