02479nas a2200205   4500008004100000022001400041245013400055210006900189260001600258520174200274100002202016700002902038700002902067700001802096700001902114700002302133700002002156700002202176856007502198       2014                        eng d  a1460-243100aProgrammed cell death activated by Rose Bengal in Arabidopsis thaliana cell suspension cultures requires functional chloroplasts.0 aProgrammed cell death activated by Rose Bengal in Arabidopsis th  c2014 Apr 103 aLight-grown Arabidopsis thaliana cell suspension culture (ACSC) were subjected to mild photooxidative damage with Rose Bengal (RB) with the aim of gaining a better understanding of singlet oxygen-mediated defence responses in plants. Additionally, ACSC were treated with H2O2 at concentrations that induced comparable levels of protein oxidation damage. Under low to medium light conditions, both RB and H2O2 treatments activated transcriptional defence responses and inhibited photosynthetic activity, but they differed in that programmed cell death (PCD) was only observed in cells treated with RB. When dark-grown ACSC were subjected to RB in the light, PCD was suppressed, indicating that the singlet oxygen-mediated signalling pathway in ACSC requires functional chloroplasts. Analysis of up-regulated transcripts in light-grown ACSC, treated with RB in the light, showed that both singlet oxygen-responsive transcripts and transcripts with a key role in hormone-activated PCD (i.e. ethylene and jasmonic acid) were present. A co-regulation analysis proved that ACSC treated with RB exhibited higher correlation with the conditional fluorescence (flu) mutant than with other singlet oxygen-producing mutants or wild-type plants subjected to high light. However, there was no evidence for the up-regulation of EDS1, suggesting that activation of PCD was not associated with the EXECUTER- and EDS1-dependent signalling pathway described in the flu mutant. Indigo Carmine and Methylene Violet, two photosensitizers unable to enter chloroplasts, did not activate transcriptional defence responses in ACSC; however, whether this was due to their location or to their inherently low singlet oxygen quantum efficiencies was not determined.1 aGutiérrez, Jorge1 aGonzález-Pérez, Sergio1 aGarcia-Garcia, Francisco1 aDaly, Cara, T1 aLorenzo, Oscar1 aRevuelta, José, L1 aMcCabe, Paul, F1 aArellano, Juan, B  uhttp://jxb.oxfordjournals.org/content/early/2014/04/09/jxb.eru151.long02438nas a2200169   4500008004100000245016300041210006900204260001500273490000600288520172300294100002202017700002902039700002902068700001902097700002202116856013002138       2011                        eng d00aDoes singlet oxygen activate cell death in Arabidopsis cell suspension cultures? Analysis of the early transcriptional defence responses to high light stress.0 aDoes singlet oxygen activate cell death in Arabidopsis cell susp  c2011 Dec 10 v63 a<p>Can Arabidopsis cell suspension cultures (ACSC) provide a useful working model to investigate genetically-controlled defence responses with signalling cascades starting in chloroplasts? In order to provide a convincing answer, we analysed the early transcriptional profile of Arabidopsis cells at high light (HL). The results showed that ACSC respond to HL in a manner that resembles the singlet oxygen ( ( 1) O 2)-mediated defence responses described for the conditional fluorescent (flu) mutant of Arabidopsis thaliana. The flu mutant is characterized by the accumulation of free protochlorophyllide (Pchlide) in plastids when put into darkness and the subsequent production of ( 1) O 2 when the light is on. In ACSC, ( 1) O 2 is produced in chloroplasts at HL when excess excitation energy flows into photosystem II (PSII). Other reactive oxygen species are also produced in ACSC at HL, but to a lesser extent. When the HL stress ceases, ACSC recovers the initial rate of oxygen evolution and cell growth continues. We can conclude that chloroplasts of ACSC are both photosynthetically active and capable of initiating ( 1) O 2-mediated signalling cascades that activate a broad range of genetically-controlled defence responses. The up-regulation of transcripts associated with the biosynthesis and signalling pathways of OPDA (12-oxophytodienoic acid) and ethylene (ET) suggests that the activated defence responses at HL are governed by these two hormones. In contrast to the flu mutant, the ( 1) O 2-mediated defence responses were independent of the up-regulation of EDS1 (enhanced disease susceptibility) required for the accumulation of salicylic acid (SA) and genetically-controlled cell death.&nbsp;</p>1 aGutiérrez, Jorge1 aGonzález-Pérez, Sergio1 aGarcia-Garcia, Francisco1 aLorenzo, Oscar1 aArellano, Juan, B  uhttp://clinbioinfosspa.es/content/does-singlet-oxygen-activate-cell-death-arabidopsis-cell-suspension-cultures-analysis-early02590nas a2200217   4500008004100000245011200041210006900153260001600222300001200238490000800250520182000258100002902078700002202107700002902129700001802158700002102176700001902197700002302216700002202239856011102261       2011                        eng d00aEarly transcriptional defence responses in Arabidopsis cell suspension culture under high light conditions.0 aEarly transcriptional defence responses in Arabidopsis cell susp  c2011 Apr 29  a1439-560 v1563 a<p>The early transcriptional defence responses and ROS production in Arabidopsis cell suspension culture (ACSC), containing functional chloroplasts, were examined at high light (HL). The transcriptional analysis revealed that most of the ROS markers identified among the 449 transcripts with significant differential expression were transcripts specifically up-regulated by singlet oxygen (1O2). On the contrary, minimal correlation was established with transcripts specifically up-regulated by superoxide radical (O2&bull;) or hydrogen peroxide (H2O2). The transcriptional analysis was supported by fluorescence microscopy experiments. The incubation of ACSC with the 1O2 sensor green reagent and 2’,7’-dichlorofluorescein diacetate showed that the 30-min-HL-treated cultures emitted fluorescence that corresponded with the production of 1O2, but not of H2O2. Furthermore, the in vivo photodamage of the D1 protein of photosystem II (PSII) indicated that the photogeneration of 1O2 took place within the PSII reaction centre. Functional enrichment analyses identified transcripts that are key components of the ROS signalling transduction pathway in plants as well as others encoding transcription factors that regulate both ROS scavenging and water deficit stress. A meta-analysis examining the transcriptional profiles of mutants and hormone treatments in Arabidopsis showed a high correlation between ACSC at HL and the flu mutant family of Arabidopsis, a producer of 1O2 in plastids. Intriguingly, a high correlation was also observed with aba1 and max4, two mutants with defects in the biosynthesis pathways of two key (apo)carotenoid-derived plant hormones (i.e. ABA and strigolactones, respectively). ACSC has proven to be a valuable system for studying early transcriptional responses to HL stress.</p>1 aGonzález-Pérez, Sergio1 aGutiérrez, Jorge1 aGarcia-Garcia, Francisco1 aOsuna, Daniel1 aDopazo, Joaquín1 aLorenzo, Oscar1 aRevuelta, José, L1 aArellano, Juan, B  uhttp://www.plantphysiol.org/content/early/2011/04/29/pp.111.177766.short?keytype=ref&ijkey=ph5B6J2khjnqwzN03501nas a2200469   4500008004100000022001400041245011200055210006900167260001300236300001200249490000800261520192600269653001602195653002202211653002802233653002002261653001702281653002102298653003002319653003802349653002202387653001002409653001302419653004402432653003502476653002802511653003102539653005202570653001902622653002402641653002602665653002702691100002902718700002202747700002902769700001802798700002002816700001902836700002302855700002202878856013102900       2011                        eng d  a1532-254800aEarly transcriptional defense responses in Arabidopsis cell suspension culture under high-light conditions.0 aEarly transcriptional defense responses in Arabidopsis cell susp  c2011 Jul  a1439-560 v1563 a<p>The early transcriptional defense responses and reactive oxygen species (ROS) production in Arabidopsis (Arabidopsis thaliana) cell suspension culture (ACSC), containing functional chloroplasts, were examined at high light (HL). The transcriptional analysis revealed that most of the ROS markers identified among the 449 transcripts with significant differential expression were transcripts specifically up-regulated by singlet oxygen ((1)O(2)). On the contrary, minimal correlation was established with transcripts specifically up-regulated by superoxide radical or hydrogen peroxide. The transcriptional analysis was supported by fluorescence microscopy experiments. The incubation of ACSC with the (1)O(2) sensor green reagent and 2',7'-dichlorofluorescein diacetate showed that the 30-min-HL-treated cultures emitted fluorescence that corresponded with the production of (1)O(2) but not of hydrogen peroxide. Furthermore, the in vivo photodamage of the D1 protein of photosystem II indicated that the photogeneration of (1)O(2) took place within the photosystem II reaction center. Functional enrichment analyses identified transcripts that are key components of the ROS signaling transduction pathway in plants as well as others encoding transcription factors that regulate both ROS scavenging and water deficit stress. A meta-analysis examining the transcriptional profiles of mutants and hormone treatments in Arabidopsis showed a high correlation between ACSC at HL and the fluorescent mutant family of Arabidopsis, a producer of (1)O(2) in plastids. Intriguingly, a high correlation was also observed with ABA deficient1 and more axillary growth4, two mutants with defects in the biosynthesis pathways of two key (apo)carotenoid-derived plant hormones (i.e. abscisic acid and strigolactones, respectively). ACSC has proven to be a valuable system for studying early transcriptional responses to HL stress.</p>10aArabidopsis10aBlotting, Western10aCell Culture Techniques10aCells, Cultured10aChloroplasts10aCluster Analysis10aGene Expression Profiling10aGene Expression Regulation, Plant10aHydrogen Peroxide10aLight10amutation10aOligonucleotide Array Sequence Analysis10aPhotosystem II Protein Complex10aPlant Growth Regulators10aReproducibility of Results10aReverse Transcriptase Polymerase Chain Reaction10aRNA, Messenger10aSignal Transduction10aStress, Physiological10aTranscription, Genetic1 aGonzález-Pérez, Sergio1 aGutiérrez, Jorge1 aGarcia-Garcia, Francisco1 aOsuna, Daniel1 aDopazo, Joaquin1 aLorenzo, Oscar1 aRevuelta, José, L1 aArellano, Juan, B  uhttp://clinbioinfosspa.es/content/early-transcriptional-defense-responses-arabidopsis-cell-suspension-culture-under-high-light