Oxidative stress induces distinct physiological responses in the two Trebouxia phycobionts of the lichen Ramalina farinacea

Hoyo, Alicia del; Álvarez, Raquel; Campo, Eva M. del; Gasulla, Francisco; Barreno, Eva; Casano, Leonardo M.

doi:10.1093/aob/mcq206

Cited by 55 publications

(27 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, in previous studies we determined that, regardless of the geographic location of this lichen, two genetically and morphologically different Trebouxia algae (provisionally named TR1 and TR9) coexist within every thallus (del Campo et al, 2010;Casano et al, 2011;del Hoyo et al, 2011). TR1 and TR9 show distinct physiological responses to the oxidative stress caused by the ROS propagator cumene hydroperoxide .…”

Section: Introductionmentioning

confidence: 94%

Different strategies to achieve Pb-tolerance by the two Trebouxia algae coexisting in the lichen Ramalina farinacea

Álvarez

Hoyo

García‐Breijo

et al. 2012

Journal of Plant Physiology

Self Cite

View full text Add to dashboard Cite

Elsevier Álvarez, R.; del Hoyo, A.; García Breijo, FJ.; Reig Armiñana, J.; Del Campo, E.; Guera, A.; Casano, L. (2012). Different strategies to achieve Pb-tolerance by the two Trebouxia algae coexisting in the lichen Ramalina farinacea. Lichen thalli are permeable to airborne substances, including heavy metals, which are harmful to cell metabolism. Ramalina farinacea shows a moderate tolerance to Pb. This lichen comprises two Trebouxia phycobionts, provisionally referred to as TR1 and TR9, with distinct physiological responses to acute oxidative stress. Thus, there is a more severe decay in photosynthesis and photosynthetic pigments in TR1 than in TR9. Similarly, under oxidative stress, antioxidant enzymes and HSP70 protein decrease in TR1 but increase in TR9. Since Pb toxicity is associated with increased ROS formation, we hypothesized greater Pb tolerance in this phycobiont. Accordingly, the aim of the present study was to characterize the physiological differences in the responses of TR1 and TR9 to Pb exposure. Liquid cultures of isolated phycobionts were incubated for 7 days in the presence of Pb(NO 3 ) 2 . Thereafter, extracellular and intracellular Pb accumulation, photosynthetic pigments, and photosynthesis (as modulated chlorophyll fluorescence) were analyzed along with the antioxidant enzymes glutathione reductase (GR), superoxide dismutase (SOD), ascorbate peroxidase (APx), and catalase (CAT), and the stress-related protein HSP70. Pb uptake increased with the amount of supplied Pb in both algae. However, while significantly more metal was immobilized extracellularly by TR9, the amount of intracellular Pb accumulation was three times higher in TR1. In neither of the phycobionts were significant effects on photosynthetic pigments or photosynthetic electron transport observed. While under control conditions GR, SOD, and APx levels were significantly higher in TR1 than in TR9, only in the latter were these enzymes induced by Pb. This resulted in quantitatively similar antioxidant activities in the two algae when exposed to Pb. In conclusion, the phycobionts of R. farinacea make use of two different strategies against stress, in which the integration of distinct anatomical and physiological features affords similar levels of Pb tolerance.

show abstract

Section: Introductionmentioning

confidence: 94%

Different strategies to achieve Pb-tolerance by the two Trebouxia algae coexisting in the lichen Ramalina farinacea

Álvarez

Hoyo

García‐Breijo

et al. 2012

Journal of Plant Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…These quantitative discrepancies could be explained, at a first glance, by putative differences in ROS-scavenging differences between TR1 and TR9 algae. However, in previous studies [1,14], we have observed that even though basal levels of antioxidant enzymes glutathione reductase, superoxide dismutase and ascorbate peroxidase were significantly higher TR1 than in TR9 (liquid cultures), Pb treatments induced the three enzymes in TR9 while it had no significant effect on those of TR1. In consequence, antioxidant activities were quantitatively similar in both phycobionts under Pb treatments [1].…”

Section: Intracellular Ros Formation and Oxidative Parameters During mentioning

confidence: 58%

“…The Trebouxia phycobionts (provisionally TR1 and TR9) coexisting in R. farinacea thalli showed distinct physiological responses to light intensity, temperature and oxidative stress generated by the ROS propagator cumene hydroperoxide [9,14]. In addition, liquid cultures of TR1 and TR9 were similarly tolerant to lead exposure, but employed different morpho-physiological strategies against the heavy metal [1].…”

Section: Intracellular Ros Formation and Oxidative Parameters During mentioning

confidence: 99%

“…Recently, we have demonstrated that each thallus of R. farinacea contains not just one, but two Trebouxia phycobionts (provisionally named TR1 and TR9). Furthermore, they show distinct ultrastructural features and physiological responses to acute oxidative stress [9,14]. In addition, when these phycobionts were incubated in a liquid medium containing Pb, the TR9 algae were able to limit the entry of the toxic metal into the cell, by holding it in the form of aggregates on the outer layer of the cell wall.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Lichen Rehydration in Heavy Metal-Polluted Environments: Pb Modulates the Oxidative Response of Both Ramalina farinacea Thalli and Its Isolated Microalgae

et al. 2014

View full text Add to dashboard Cite

Lichens are adapted to desiccation/rehydration and accumulate heavy metals, which induce ROS especially from the photobiont photosynthetic pigments. Although their mechanisms of abiotic stress tolerance are still to be unravelled, they seem related to symbionts' reciprocal upregulation of antioxidant systems. With the aim to study the effect of Pb on oxidative status during rehydration, the kinetics of intracellular ROS, lipid peroxidation and chlorophyll autofluorescence of whole Ramalina farinacea thalli and its isolated microalgae (Trebouxia TR1 and T. TR9) was recorded. A genetic characterization of the microalgae present in the thalli used was also carried out in order to assess possible correlations among the relative abundance of each phycobiont, their individual physiological responses and that of the entire thallus. Unexpectedly, Pb decreased ROS and lipid peroxidation in thalli and its phycobionts, associated with a lower chlorophyll autofluorescence. Each phycobiont showed a particular pattern, but the oxidative response of the thallus paralleled the TR1's, agreeing with the genetic identification of this strain as the predominant phycobiont. We conclude that: (1) the lichen oxidative behaviour seems to be modulated by the predominant phycobiont and (2) Pb evokes in R. farinacea and its phycobionts strong mechanisms to neutralize its own oxidant effects along with those of rehydration.

show abstract

“…Many chlorolichens contains more than one photobiont. For instance, Ramalina farinacea includes two different Trebouxia photobionts (TR1 and TR9) and isolation of these algae allowed to characterise physiological differences between both of them (Casano et al, 2010;del Hoyo et al, 2011). There are different methods in function of the objective of investigation.…”

Section: Methods For Isolating Lichen Photobiontsmentioning

confidence: 99%

Photosynthesis in Lichen: Light Reactions and Protective Mechanisms

Gasulla¹,

Herrero²,

Esteban³

et al. 2012

Advances in Photosynthesis - Fundamental Aspects

Self Cite

View full text Add to dashboard Cite

Oxidative stress induces distinct physiological responses in the two Trebouxia phycobionts of the lichen Ramalina farinacea

Abstract: The better physiological performance of TR9 under oxidative conditions may reflect its greater capacity to undertake key metabolic adjustments, including increased non-photochemical quenching, higher antioxidant protection and the induction of repair mechanisms.

Cited by 55 publications

References 41 publications

Different strategies to achieve Pb-tolerance by the two Trebouxia algae coexisting in the lichen Ramalina farinacea

Different strategies to achieve Pb-tolerance by the two Trebouxia algae coexisting in the lichen Ramalina farinacea

Lichen Rehydration in Heavy Metal-Polluted Environments: Pb Modulates the Oxidative Response of Both Ramalina farinacea Thalli and Its Isolated Microalgae

Photosynthesis in Lichen: Light Reactions and Protective Mechanisms

Contact Info

Product

Resources

About