Phenolic-nitrogen interactions in eelgrass, Zostera marina L.: possible implications for disease resistance

Buchsbaum, Robert; Short, Frederick T.; Cheney, Donald P.

doi:10.1016/0304-3770(90)90075-v

Cited by 69 publications

(46 citation statements)

References 22 publications

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“…Such a chronic exposure to NH 4 + (i.e., several months or years) will most likely lead to the classically reported visual symptoms like chlorosis of leaves and the suppression of growth (Britto and Kronzucker 2002). Moreover, phenolic content in the leaves will decrease, due to a changed allocation of carbon skeletons, making the plant more susceptible to pathogens like the "wasting disease", which destroyed many eelgrass stands in the 1930s (Buchsbaum et al 1990;van Katwijk et al 1997;Vergeer and Develi 1997). Although high NH x levels in the water layer at pH 8 most likely cause stress in eelgrass when exposed for longer periods of time, results from our experiments demonstrate that acute toxicity and sudden collapse through mass mortality will probably not occur as long as suYcient light is available.…”

Section: Ecological Implicationsmentioning

confidence: 99%

Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

et al. 2008

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In sheltered, eutrophicated estuaries, reduced nitrogen (NH x ), and pH levels in the water layer can be greatly enhanced. In laboratory experiments, we studied the interactive eVects of NH x , pH, and shoot density on the physiology and survival of eelgrass (Zostera marina). We tested long-term tolerance to NH x at pH 8 in a 5-week experiment. Short-term tolerance was tested for two shoot densities at both pH 8 and 9 in a 5-day experiment. At pH 8, eelgrass accumulated nitrogen as free amino acids when exposed to high loads of NH x , but showed no signs of necrosis. Low shoot density treatments became necrotic within days when exposed to NH x at pH 9. Increased NH 3 intrusion and carbon limitation seemed to be the cause of this, as intracellular NH x could no longer be assimilated.Remarkably, experiments with high shoot densities at pH 9 showed hardly any necrosis, as the plants seemed to be able to alleviate the toxic eVects of high NH x loads through joint NH x uptake. Our results suggest that NH x toxicity can be important in worldwide observed seagrass mass mortalities. We argue that the mitigating eVect of high seagrass biomass on NH x toxicity is a positive feedback mechanism, potentially leading to alternative stable states in Weld conditions.

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Section: Ecological Implicationsmentioning

confidence: 99%

Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

et al. 2008

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“…However, it remains unclear what triggers disease outbreaks. Environmental conditions such as reduced irradiance, elevated temperatures, high salinities and unfavorable types of benthic substrate have been reported to increase the probability of wasting disease symptoms in eelgrass (Short et al 1988, Buchsbaum et al 1990, Burdick et al 1993. In addition, the health of the plant is also an important factor, as Short et al (1988) demonstrated that Labyrinthula sp.…”

Section: Introductionmentioning

confidence: 99%

“…For example, the accumulation of phenolic substances in Zostera marina has been correlated with reduced microbial growth and herbivory (Harrison 1982), and with resistance to the wasting disease in mesocosm experiments (Buchsbaum et al 1990) and in the field (Vergeer & Den Hartog 1991, Vergeer & Develi 1997. Seagrasses are a rich source of (poly)phenolics, including simple and sulfated phenolic acids and condensed (but not hydrolysable) tannins, many of which have demonstrated antimicrobial properties in other plant -pathogen interactions (Arnold & Targett 2002).…”

Section: Introductionmentioning

confidence: 99%

Seagrasspathogen interactions: pseudo-induction of turtlegrass phenolics near wasting disease lesions

Steele¹,

Caldwell²,

Boettcher³

et al. 2005

Mar. Ecol. Prog. Ser.

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Marine protists of the genus Labyrinthula cause the seagrass wasting disease, which is associated with regional die-offs of eelgrass Zostera marina and also infects turtlegrass Thalassia testudinum. The ability of seagrasses to resist pathogen attack is determined by multiple factors, which are poorly understood. One factor hypothesized to influence seagrass disease resistance is the presence of (poly)phenolic natural products such as caffeic acid, which inhibits the growth of L. zosterae in in vitro laboratory bioassays. This hypothesis has been supported by reports of pathogen-induced phenolic accumulations in eelgrass Z. marina. To test the response of T. testudinum to inoculation with Labyrinthula sp., we conducted a series of culture experiments wherein plants were inoculated with Labyrinthula sp. isolated from turtlegrass beds in Perdido Bay, Florida (USA). Concentrations of phenolic acids and condensed tannins were quantified in diseased leaves as well as those treated with 5 mM salicylic acid, a signaling molecule associated with pathogen-induced responses in plants.In infection experiments, increases in the concentrations of several phenolic acids, but not condensed tannins, were observed in tissues above, but not below, microbial lesions. Salicylic acid (SA) treatments did not induce any phenolic compound, either when applied alone or in concert with the pathogen. The induction of phenolic acids above, but not below, infection sites suggests that T. testudinum leaves did not respond to the pathogen specifically. Instead, the pattern is consistent with the predictions of the sink/source model of plant defense, which predicts increased phenolic contents in cases where wounds disrupt plant resource allocation and cause a local overabundance of carbonbased resources. Thus, we suggest that the emergence of Labyrinthula sp. lesions on turtlegrass blades causes a 'pseudo-induction' of specific phenolics as carbon resources over-accumulate in tissues located above wound sites.

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“…Phenolic acids known to inhibit the growth of the seagrass wasting disease pathogen, Layrinthula spp., were reduced by as much as~95% under "acidified" conditions. Such decreases in protective phenolic compounds have been linked to wasting disease outbreaks and seagrass mortality (e.g., Vergeer and Develi 1997;Buchsbaum, Short, and Cheney 1990;Vergeer, Aarts, and De Groot 1995). Interestingly, acidification also reduces the concentration of bioactive polyphenols in brown algae (e.g., Korbee et al 2014;Yildiz and Dere 2015).…”

Section: Coastal Zone Acidificationmentioning

confidence: 99%

Twenty-first century climate change and submerged aquatic vegetation in a temperate estuary: the case of Chesapeake Bay

Arnold

Zimmerman

Engelhardt

et al. 2017

Ecosyst Health Sustain

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Introduction: The Chesapeake Bay was once renowned for expansive meadows of submerged aquatic vegetation (SAV). However, only 10% of the original meadows survive. Future restoration efforts will be complicated by accelerating climate change, including physiological stressors such as a predicted mean temperature increase of 2-6°C and a 50-160% increase in CO 2 concentrations. Outcomes: As the Chesapeake Bay begins to exhibit characteristics of a subtropical estuary, summer heat waves will become more frequent and severe. Warming alone would eventually eliminate eelgrass (Zostera marina) from the region. It will favor native heat-tolerant species such as widgeon grass (Ruppia maritima) while facilitating colonization by non-native seagrasses (e.g., Halodule spp.). Intensifying human activity will also fuel coastal zone acidification and the resulting high CO 2 /low pH conditions may benefit SAV via a "CO 2 fertilization effect." Discussion: Acidification is known to offset the effects of thermal stress and may have similar effects in estuaries, assuming water clarity is sufficient to support CO 2 -stimulated photosynthesis and plants are not overgrown by epiphytes. However, coastal zone acidification is variable, driven mostly by local biological processes that may or may not always counterbalance the effects of regional warming. This precarious equipoise between two forcesthermal stress and acidification -will be critically important because it may ultimately determine the fate of cool-water plants such as Zostera marina in the Chesapeake Bay. Conclusion: The combined impacts of warming, coastal zone acidification, water clarity, and overgrowth of competing algae will determine the fate of SAV communities in rapidly changing temperate estuaries.

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Phenolic-nitrogen interactions in eelgrass, Zostera marina L.: possible implications for disease resistance

Cited by 69 publications

References 22 publications

Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

Seagrasspathogen interactions: pseudo-induction of turtlegrass phenolics near wasting disease lesions

Twenty-first century climate change and submerged aquatic vegetation in a temperate estuary: the case of Chesapeake Bay

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Phenolic-nitrogen interactions in eelgrass, Zostera marina L.: possible implications for disease resistance

Cited by 69 publications

References 22 publications

Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

Seagrasspathogen interactions: pseudo-induction of turtlegrass phenolics near wasting disease lesions

Twenty-first century climate change and submerged aquatic vegetation in a temperate estuary: the case of Chesapeake Bay

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Seagrasspathogen interactions: pseudo-induction of turtlegrass phenolics near wasting disease lesions