@article{AlluBrotmanXueetal.2016, author = {Allu, Annapurna Devi and Brotman, Yariv and Xue, Gang-Ping and Balazadeh, Salma}, title = {Transcription factor ANAC032 modulates JA/SA signalling in response to Pseudomonas syringae infection}, series = {EMBO reports}, volume = {17}, journal = {EMBO reports}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1469-221X}, doi = {10.15252/embr.201642197}, pages = {1578 -- 1589}, year = {2016}, abstract = {Responses to pathogens, including host transcriptional reprogramming, require partially antagonistic signalling pathways dependent on the phytohormones salicylic (SA) and jasmonic (JA) acids. However, upstream factors modulating the interplay of these pathways are not well characterized. Here, we identify the transcription factor ANAC032 from Arabidopsis thaliana as one such regulator in response to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst). ANAC032 directly represses MYC2 activation upon Pst attack, resulting in blockage of coronatine-mediated stomatal reopening which restricts entry of bacteria into plant tissue. Furthermore, ANAC032 activates SA signalling by repressing NIMIN1, a key negative regulator of SA-dependent defence. Finally, ANAC032 reduces expression of JA-responsive genes, including PDF1.2A. Thus, ANAC032 enhances resistance to Pst by generating an orchestrated transcriptional output towards key SA- and JA-signalling genes coordinated through direct binding of ANAC032 to the MYC2, NIMIN1 and PDF1.2A promoters.}, language = {en} } @article{AlluSimancasBalazadehetal.2017, author = {Allu, Annapurna Devi and Simancas, Barbara and Balazadeh, Salma and Munne-Bosch, Sergi}, title = {Defense-Related Transcriptional Reprogramming in Vitamin E-Deficient Arabidopsis Mutants Exposed to Contrasting Phosphate Availability}, series = {Frontiers in plant science}, volume = {8}, journal = {Frontiers in plant science}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2017.01396}, pages = {20}, year = {2017}, abstract = {Vitamin E inhibits the propagation of lipid peroxidation and helps protecting photosystem II from photoinhibition, but little is known about its possible role in plant response to Pi availability. Here, we aimed at examining the effect of vitamin E deficiency in Arabidopsis thaliana vte mutants on phytohormone contents and the expression of transcription factors in plants exposed to contrasting Pi availability. Plants were subjected to two doses of Pi, either unprimed (controls) or previously exposed to low Pi (primed). In the wild type, alpha-tocopherol contents increased significantly in response to repeated periods of low Pi, which was paralleled by increased growth, indicative of a priming effect. This growth-stimulating effect was, however, abolished in vte mutants. Hormonal profiling revealed significant effects of Pi availability, priming and genotype on the contents of jasmonates and salicylates; remarkably, vte mutants showed enhanced accumulation of both hormones under low Pi. Furthermore, expression profiling of 1,880 transcription factors by qRT-PCR revealed a pronounced effect of priming on the transcript levels of 45 transcription factors mainly associated with growth and stress in wild-type plants in response to low Pi availability; while distinct differences in the transcriptional response were detected in vte mutants. We conclude that alpha-tocopherol plays a major role in the response of plants to Pi availability not only by protecting plants from photo-oxidative stress, but also by exerting a control over growth-and defense-related transcriptional reprogramming and hormonal modulation.}, language = {en} } @article{AlluSojaWuetal.2014, author = {Allu, Annapurna Devi and Soja, Aleksandra Maria and Wu, Anhui and Szymanski, Jedrzej and Balazadeh, Salma}, title = {Salt stress and senescence: identification of cross-talk regulatory components}, series = {Journal of experimental botany}, volume = {65}, journal = {Journal of experimental botany}, number = {14}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0022-0957}, doi = {10.1093/jxb/eru173}, pages = {3993 -- 4008}, year = {2014}, abstract = {Leaf senescence is an active process with a pivotal impact on plant productivity. It results from extensive signalling cross-talk coordinating environmental factors with intrinsic age-related mechanisms. Although many studies have shown that leaf senescence is affected by a range of external parameters, knowledge about the regulatory systems that govern the interplay between developmental programmes and environmental stress is still vague. Salinity is one of the most important environmental stresses that promote leaf senescence and thus affect crop yield. Improving salt tolerance by avoiding or delaying senescence under stress will therefore play an important role in maintaining high agricultural productivity. Experimental evidence suggests that hydrogen peroxide (H2O2) functions as a common signalling molecule in both developmental and salt-induced leaf senescence. In this study, microarray-based gene expression profiling on Arabidopsis thaliana plants subjected to long-term salinity stress to induce leaf senescence was performed, together with co-expression network analysis for H2O2-responsive genes that are mutually up-regulated by salt induced-and developmental leaf senescence. Promoter analysis of tightly co-expressed genes led to the identification of seven cis-regulatory motifs, three of which were known previously, namely CACGTGT and AAGTCAA, which are associated with reactive oxygen species (ROS)-responsive genes, and CCGCGT, described as a stress-responsive regulatory motif, while the others, namely ACGCGGT, AGCMGNC, GMCACGT, and TCSTYGACG were not characterized previously. These motifs are proposed to be novel elements involved in the H2O2-mediated control of gene expression during salinity stress-triggered and developmental senescence, acting through upstream transcription factors that bind to these sites.}, language = {en} } @article{AlshareefOtterbachAlluetal.2022, author = {Alshareef, Nouf Owdah and Otterbach, Sophie L. and Allu, Annapurna Devi and Woo, Yong H. and de Werk, Tobias and Kamranfar, Iman and M{\"u}ller-R{\"o}ber, Bernd and Tester, Mark and Balazadeh, Salma and Schm{\"o}ckel, Sandra M.}, title = {NAC transcription factors ATAF1 and ANAC055 affect the heat stress response in Arabidopsis}, series = {Scientific reports}, volume = {12}, journal = {Scientific reports}, number = {1}, publisher = {Nature Research}, address = {Berlin}, issn = {2045-2322}, doi = {10.1038/s41598-022-14429-x}, pages = {15}, year = {2022}, abstract = {Pre-exposing (priming) plants to mild, non-lethal elevated temperature improves their tolerance to a later higher-temperature stress (triggering stimulus), which is of great ecological importance. 'Thermomemory' is maintaining this tolerance for an extended period of time. NAM/ATAF1/2/ CUC2 (NAC) proteins are plant-specific transcription factors (TFs) that modulate responses to abiotic stresses, including heat stress (HS). Here, we investigated the potential role of NACs for thermomemory. We determined the expression of 104 Ara bidopsis NAC genes after priming and triggering heat stimuli, and found ATAF1 expression is strongly induced right after priming and declines below control levels thereafter during thermorecovery. Knockout mutants of ATAF1 show better thermomemory than wild type, revealing a negative regulatory role. Differential expression analyses of RNA-seq data from ATAF1 overexpressor, ataf1 mutant and wild-type plants after heat priming revealed five genes that might be priming-associated direct targets of ATAF1: AT2G31260 (ATG9), AT2G41640 (GT61), AT3G44990 (XTH31), AT4G27720 and AT3G23540. Based on co-expression analyses applied to the aforementioned RNA-seq profiles, we identified ANAC055 to be transcriptionally co-regulated with ATAF1. Like atafl, anac055 mutants show improved thermomemory, revealing a potential co-control of both NACTFs over thermomemory. Our data reveals a core importance of two NAC transcription factors, ATAF1 and ANAC055, for thermomemory.}, language = {en} } @phdthesis{Balazadeh2008, author = {Balazadeh, Salma}, title = {Molecular and physiological analysis of leaf senescence in Arabidopsis thaliana}, pages = {VI, 169 S.}, year = {2008}, language = {en} } @unpublished{Balazadeh2014, author = {Balazadeh, Salma}, title = {Stay-green not always stays green}, series = {Molecular plant}, volume = {7}, journal = {Molecular plant}, number = {8}, publisher = {Cell Press}, address = {Cambridge}, issn = {1674-2052}, doi = {10.1093/mp/ssu076}, pages = {1264 -- 1266}, year = {2014}, language = {en} } @phdthesis{Balazadeh2015, author = {Balazadeh, Salma}, title = {New insights into the molecular mechanisms of leaf senescence}, school = {Universit{\"a}t Potsdam}, year = {2015}, language = {en} } @article{BalazadehJaspertArifetal.2012, author = {Balazadeh, Salma and Jaspert, Nils and Arif, Muhammad and M{\"u}ller-R{\"o}ber, Bernd and Maurino, Veronica G.}, title = {Expression of ROS-responsive genes and transcription factors after metabolic formation of H2O2 in chloroplasts}, series = {Frontiers in plant science}, volume = {3}, journal = {Frontiers in plant science}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2012.00234}, pages = {30}, year = {2012}, abstract = {Glycolate oxidase (GO) catalyses the oxidation of glycolate to glyoxylate, thereby consuming O-2 and producing H2O2. In this work, Arabidopsis thaliana plants expressing GO in the chloroplasts (GO plants) were used to assess the expressional behavior of reactive oxygen species (ROS)-responsive genes and transcription factors (TFs) after metabolic induction of H2O2 formation in chloroplasts. In this organelle, GO uses the glycolate derived from the oxygenase activity of RubisCO. Here, to identify genes responding to an abrupt production of H2O2 in chloroplasts we used quantitative real-time PCR (qRT-PCR) to test the expression of 187 ROS-responsive genes and 1880 TFs after transferring GO and wild-type (WT) plants grown at high CO2 levels to ambient CO2 concentration. Our data revealed coordinated expression changes of genes of specific functional networks 0.5 h after metabolic induction of H2O2 production in GO plants, including the induction of indole glucosinolate and camalexin biosynthesis genes. Comparative analysis using available microarray data suggests that signals for the induction of these genes through H2O2 may originate in the chloroplast. The TF profiling indicated an up-regulation in GO plants of a group of genes involved in the regulation of proanthocyanidin and anthocyanin biosynthesis. Moreover, the upregulation of expression of IF and IF interacting proteins affecting development (e.g., cell division, stem branching, flowering time, flower development) would impact growth and reproductive capacity, resulting in altered development under conditions that promote the formation of H2O2.}, language = {en} } @article{BalazadehKwasniewskiCaldanaetal.2011, author = {Balazadeh, Salma and Kwasniewski, Miroslaw and Caldana, Camila and Mehrnia, Mohammad and Zanor, Maria Ines and Xue, Gang-Ping and M{\"u}ller-R{\"o}ber, Bernd}, title = {ORS1, an H2O2-Responsive NAC Transcription Factor, Controls Senescence in Arabidopsis thaliana}, series = {Molecular plant}, volume = {4}, journal = {Molecular plant}, number = {2}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {1674-2052}, doi = {10.1093/mp/ssq080}, pages = {346 -- 360}, year = {2011}, abstract = {We report here that ORS1, a previously uncharacterized member of the NAC transcription factor family, controls leaf senescence in Arabidopsis thaliana. Overexpression of ORS1 accelerates senescence in transgenic plants, whereas its inhibition delays it. Genes acting downstream of ORS1 were identified by global expression analysis using transgenic plants producing dexamethasone-inducible ORS1-GR fusion protein. Of the 42 up-regulated genes, 30 (similar to 70\%) were previously shown to be up-regulated during age-dependent senescence. We also observed that 32 (similar to 76\%) of the ORS1-dependent genes were induced by long-term (4 d), but not short-term (6 h) salinity stress (150 mM NaCl). Furthermore, expression of 16 and 24 genes, respectively, was induced after 1 and 5 h of treatment with hydrogen peroxide (H2O2), a reactive oxygen species known to accumulate during salinity stress. ORS1 itself was found to be rapidly and strongly induced by H2O2 treatment in both leaves and roots. Using in vitro binding site selection, we determined the preferred binding motif of ORS1 and found it to be present in half of the ORS1-dependent genes. ORS1 is a paralog of ORE1/ANAC092/AtNAC2, a previously reported regulator of leaf senescence. Phylogenetic footprinting revealed evolutionary conservation of the ORS1 and ORE1 promoter sequences in different Brassicaceae species, indicating strong positive selection acting on both genes. We conclude that ORS1, similarly to ORE1, triggers expression of senescence-associated genes through a regulatory network that may involve cross-talk with salt- and H2O2-dependent signaling pathways.}, language = {en} } @misc{BalazadehMuellerRoeber2018, author = {Balazadeh, Salma and M{\"u}ller-R{\"o}ber, Bernd}, title = {A balance to death}, series = {Nature plants}, volume = {4}, journal = {Nature plants}, number = {11}, publisher = {Nature Publ. Group}, address = {London}, issn = {2055-026X}, doi = {10.1038/s41477-018-0279-6}, pages = {863 -- 864}, year = {2018}, abstract = {Leaf senescence plays a crucial role in nutrient recovery in late-stage plant development and requires vast transcriptional reprogramming by transcription factors such as ORESARA1 (ORE1). A proteolytic mechanism is now found to control ORE1 degradation, and thus senescence, during nitrogen starvation.}, language = {en} }