title: Salt stress and senescence: identification of cross-talk regulatory components.
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.
authors.affiliation: University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Straße 24-25, Haus 20, D-14476 Potsdam-Golm, Germany Max-Planck Institute of Molecular Plant Physiology, Plant Signaling Group, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
authors.forename: Annapurna Devi
authors.initials: AD
authors.lastname: Allu
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Department of Molecular Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
authors.forename: Aleksandra Maria
authors.initials: AM
authors.lastname: Soja
authors.affiliation: University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Straße 24-25, Haus 20, D-14476 Potsdam-Golm, Germany.
authors.forename: Anhui
authors.initials: A
authors.lastname: Wu
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Department of Molecular Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
authors.forename: Jedrzej
authors.initials: J
authors.lastname: Szymanski
authors.affiliation: University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Straße 24-25, Haus 20, D-14476 Potsdam-Golm, Germany Max-Planck Institute of Molecular Plant Physiology, Plant Signaling Group, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany balazadeh@mpimp-golm.mpg.de.
authors.forename: Salma
authors.initials: S
authors.lastname: Balazadeh
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology; D001483:Base Sequence; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D053263:Gene Regulatory Networks; D006861:Hydrogen Peroxide / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D005810:Multigene Family; D059372:Nucleotide Motifs / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D054712:Salinity; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects* / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics
chemical_list: D012965:Sodium Chloride; D006861:Hydrogen Peroxide
keywords: Arabidopsis; hydrogen peroxide; longevity; reactive oxygen species; salt stress; senescence; signal cross-talk; transcription factor.