Novel amplification of non‐photochemical chlorophyll fluorescence quenching following viral infection in <i>Chlorella</i>

Seaton, G. G. R.; Hurry, Vaughan; Rohozinski, Jan

doi:10.1016/0014-5793(96)00615-1

Cited by 22 publications

(13 citation statements)

References 23 publications

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“…Typically, inhibition of photosynthesis occurs as a result of indirect viral interference with electron flow, thought to be associated with the change from host protein and nucleic acid synthesis to synthesis of virus-encoded protein and nucleic acid (Teklemariam et al 1990, Seaton et al 1995. Subsequently, there is a loss of PSII-PSI electron transport efficiency due to destabilisation of PSII-dependent protein turnover (Van Etten et al 1991), observed as a reduction in photochemical quenching and an increase in fluorescence quenching, and indicated by a decrease in darkadapted F v /F m (Teklemariam et al 1990, Seaton et al 1995, Seaton et al 1996, Balachandran et al 1997, Rahoutei et al 2000, Hewson et al 2001, Juneau et al 2003. Furthermore, oxidative stress is elevated within infected cells (Schwarz 1996, Evans et al 2006, Bidle et al 2007, Vardi et al 2009), and the production of reactive oxygen species (ROS) through viral-induced destabilisation of PSII turnover has been suggested as a causal factor (Balachandran et al 1997, Evans et al 2006).…”

Section: Discussionmentioning

confidence: 95%

Reduction in photosystem II efficiency during a virus-controlled Emiliania huxleyi bloom

Kimmance¹,

Allen²,

Pagarete³

et al. 2014

Mar. Ecol. Prog. Ser.

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During viral infection of Emiliania huxleyi, laboratory studies have shown that photosystem (PS) II efficiency declines during the days post-infection and is thought to be associated with viral-induced interruption of electron transport rates between photosystems. However, measuring the impact of viral infection on PSII function in E. huxleyi populations from natural, taxo nomically diverse phytoplankton communities is difficult, and whether this phenomenon occurs in nature is presently unknown. Here, chlorophyll fluorescence analysis was used to assess changes in PSII efficiency throughout an E. huxleyi bloom during a mesocosm experiment off the coast of Norway. Specifically, we aimed to determine whether a measurable suppression of the efficiency of PSII photochemistry could be observed due to viral infection of the natural E. huxleyi populations. During the major infection period prior to bloom collapse, there was a significant reduction in PSII efficiency with an average decrease in maximum PSII photochemical efficiency (F v /F m ) of 17% and a corresponding 75% increase in maximum PSII effective absorption crosssection (σ PSII ); this was concurrent with a significant decrease in E. huxleyi growth rates and an increase in E. huxleyi virus (EhV) production. As E. huxleyi populations dominated the phytoplankton community and potentially contributed up to 100% of the chlorophyll a pool, we believe that the variable chlorophyll fluorescence signal measured during this period was derived predominantly from E. huxleyi and, thus, reflects changes occurring within E. huxleyi cells. This is the first demonstration of suppression of PSII photochemistry occurring during viral infection of natural coccolithophore populations. KEY WORDS: Viral infection · Emiliania huxleyi bloom · Chlorophyll fluorescence · Photosystem II efficiency · MesocosmResale or republication not permitted without written consent of the publisher Editorial responsibility: Katherine Richardson,

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Section: Discussionmentioning

confidence: 95%

Reduction in photosystem II efficiency during a virus-controlled Emiliania huxleyi bloom

Kimmance¹,

Allen²,

Pagarete³

et al. 2014

Mar. Ecol. Prog. Ser.

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“…Here, the virus induces heat dissipation of excess light energy away from PSI! (non-photochemical quenching, NPQ) to prevent damage (Seaton et al, 1996). In the absence of the virus, this protective mechanism is poorly developed in aquatic marine algae such as Chiarella (Buchel and Wilhelm, 1993).…”

Section: Viruses As Mutualistsmentioning

confidence: 99%

Coral-virus interactions: A double-edged sword?

2009

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Marine viruses were little studied until 1989, when they were discovered to be extremely abundant in the sea. Virology is now a growing field of science in coral reef research, largely related to an increase in the frequency of coral bleaching events and other coral diseases. Because viruses are obligate syrnbionts, they are generally perceived as parasitic and harmful to their hosts. However, evidence that viruses confer benefits to their hosts is growing and their role as rnutualists is emerging. Here we review both the detrimental and beneficial aspects of viral infections and argue that as the field of coral virology expands, in addition to their pathogenicity, the idea that viruses represent functionally beneficial components of the coral holobiont be considered.

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“…The biotic stress has particular effects on photosynthesis (Osmond et al, 1990, 19, 7) and especially on photosystem 2 (18,12,20). The tabtoxin destroys chloroplasts and inhibits the many key enzymes in the photorespiratory nitrogen cycle.…”

Section: Introductionmentioning

confidence: 97%

The Changes in Some Photosynthetic Characteristics of Transgenic Tobacco Plants, Resistant to BacteriaPseudomonas Syringaepv. Tabaci

Kapchina

Milanov

Zankov

et al. 2004

Biotechnology & Biotechnological Equipment

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The changes in the photosynthetic reactions of tobacco plants, infected by Pseudomonas syringae pv. tabaci were investigated. The protection against pathogen were studied in sensitive to wildfire disease tobacco plants -Nevrokop 1146 (N1146) and pigment deficient "aurea-like mutant", A1146. The responses were compared with a transgenic resistant line of Nevrokop 1146 -(T1146) developed by Batchvarova et al, (1998) and carrying the ttr (tabtoxin resistance) gene. The changes in thylakoid electron transport, especially on PS2, were evaluated by induction curves of variable and the delayed fluorescence. Correlation with some changes in enzymatic processes related to fast and slow protection against pathogen was also investigated. More expressed effects of infection on photosynthesis in N1146 and A1146 than in T1146 were probably due to the direct tabtoxin action on both chlorophyll a and b. The hypersensitive reaction was expressed during the initial stages of the bacterial infection as evaluated by enhanced peroxidase activity. The increase in reduced sugars and α − amylase activity was related to development of later stages of protection against pathogen. The investigations showed that the changes in the photosynthetic apparatus could not only be correlated to the tabtoxin action and thence limited photorespiration. The resistant T1146 did not develop typical disease symptoms because of the limited tabtoxin action but pathogen induced changes in photosynthesis were obtained. The differences in the effects in N1146 and A1146 were probably due to their possible different chloroplast structure.

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Novel amplification of non‐photochemical chlorophyll fluorescence quenching following viral infection in Chlorella

Cited by 22 publications

References 23 publications

Reduction in photosystem II efficiency during a virus-controlled Emiliania huxleyi bloom

Reduction in photosystem II efficiency during a virus-controlled Emiliania huxleyi bloom

Coral-virus interactions: A double-edged sword?

The Changes in Some Photosynthetic Characteristics of Transgenic Tobacco Plants, Resistant to BacteriaPseudomonas Syringaepv. Tabaci

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