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Apeldoorn, Netherlands

Bailey-Serres J.,University of California at Riverside | Voesenek L.A.C.J.,University Utrecht | Voesenek L.A.C.J.,Center for Biosystems Genomics
Current Opinion in Plant Biology | Year: 2010

Recent reports on responses to flooding, submergence, and low-oxygen stress have connected components in an essential regulatory network that underlies plasticity in growth and metabolism essential for the survival of distinct flooding regimes. Here, we discuss growth under severe oxygen-limited conditions (anaerobic growth) and less oxygen-deficient underwater conditions (ethylene-driven underwater growth). Low-oxygen stress causes an energy and carbohydrate crisis that must be controlled through regulated consumption of carbohydrates and energy reserves. In rice (Oryza sativa L.), low-oxygen stress, energy homeostasis and growth are connected by a calcineurin B-like interacting binding kinase (CIPK) in seeds germinated under water. In shoots, two opposing adaptive strategies to submergence, elongation (escape) and inhibition of elongation (quiescence), are controlled by related ethylene response factor (ERF) DNA binding proteins that act downstream of ethylene and modulate gibberellin-mediated shoot growth. Increased resolution of the flooding signaling network will require more precise investigation of the interactions between oxygen tension and cellular energy status in regulation of anaerobic metabolism and ethylene-driven growth, both essential to survival in variable flooding environments. © 2010 Elsevier Ltd.

Takken F.L.W.,University of Amsterdam | Takken F.L.W.,Center for Biosystems Genomics | Goverse A.,Wageningen University | Goverse A.,Center for Biosystems Genomics
Current Opinion in Plant Biology | Year: 2012

Many plant disease resistance (R) proteins belong to the family of nucleotide-binding-leucine rich repeat (NB-LRR) proteins. NB-LRRs mediate recognition of pathogen-derived effector molecules and subsequently activate host defence. Their multi-domain structure allows these pathogen detectors to simultaneously act as sensor, switch and response factor. Structure-function analyses and the recent elucidation of the 3D structures of subdomains have provided new insight in how these different functions are combined and what the contribution is of the individual subdomains. Besides interdomain contacts, interactions with chaperones, the proteasome and effector baits are required to keep NB-LRRs in a signalling-competent, yet auto-inhibited state. In this review we explore operational models of NB-LRR functioning based on recent advances in understanding their structure. © 2012 Elsevier Ltd.

Al-Babili S.,King Abdullah University of Science and Technology | Bouwmeester H.J.,Wageningen University | Bouwmeester H.J.,Center for Biosystems Genomics
Annual Review of Plant Biology | Year: 2015

Strigolactones (SLs) are carotenoid-derived plant hormones and signaling molecules. When released into the soil, SLs indicate the presence of a host to symbiotic fungi and root parasitic plants. In planta, they regulate several developmental processes that adapt plant architecture to nutrient availability. Highly branched/tillered mutants in Arabidopsis, pea, and rice have enabled the identification of four SL biosynthetic enzymes: a cis/trans-carotene isomerase, two carotenoid cleavage dioxygenases, and a cytochrome P450 (MAX1). In vitro and in vivo enzyme assays and analysis of mutants have shown that the pathway involves a combination of new reactions leading to carlactone, which is converted by a rice MAX1 homolog into an SL parent molecule with a tricyclic lactone moiety. In this review, we focus on SL biosynthesis, describe the hormonal and environmental factors that determine this process, and discuss SL transport and downstream signaling as well as the role of SLs in regulating plant development. ©2015 by Annual Reviews. All rights reserved.

Sasidharan R.,University Utrecht | Sasidharan R.,Center for Biosystems Genomics | Mustroph A.,University of Bayreuth
Plant Cell | Year: 2011

Like all aerobic organisms, plants require molecular oxygen for respiratory energy production. In plants, hypoxic conditions can occur during natural events (e.g., flooding), during developmental processes (e.g., seed germination), and in cells of compact tissues with high metabolic rates. Plant acclimation responses to hypoxia involve a modulation of gene expression leading to various biochemical, physiological, and morphological changes that stave off eventual anoxia. In contrast with the animal kingdom, a direct oxygen-sensing mechanism in plants has been elusive so far. However, two recent independent studies show that oxygen sensing in plants operates via posttranslational regulation of key hypoxia response transcription factors by the N-end rule pathway. The N-end rule is an evolutionarily conserved pathway for protein degradation that relates the fate of a protein with the identity of its N-terminal residues. Results from these studies demonstrate that oxygen-dependent modification and targeted proteolysis of members of the ethylene response factor group VII transcription factor family regulate hypoxia-responsive gene expression in Arabidopsis thaliana. The discovery of this plant hypoxia-sensing mechanism sets the stage for further research on plant homeostatic response to oxygen, which could be relevant to understanding plant distributions in flood-prone ecosystems and improving hypoxia tolerance of crops. © 2011 American Society of Plant Biologists.

Pieterse C.M.J.,University Utrecht | Pieterse C.M.J.,Center for Biosystems Genomics | Van Der Does D.,University Utrecht | Zamioudis C.,University Utrecht | And 2 more authors.
Annual Review of Cell and Developmental Biology | Year: 2012

Plant hormones have pivotal roles in the regulation of plant growth, development, and reproduction. Additionally, they emerged as cellular signal molecules with key functions in the regulation of immune responses to microbial pathogens, insect herbivores, and beneficial microbes. Their signaling pathways are interconnected in a complex network, which provides plants with an enormous regulatory potential to rapidly adapt to their biotic environment and to utilize their limited resources for growth and survival in a cost-efficient manner. Plants activate their immune system to counteract attack by pathogens or herbivorous insects. Intriguingly, successful plant enemies evolved ingenious mechanisms to rewire the plant's hormone signaling circuitry to press or evade host immunity. Evidence is emerging that beneficial root-inhabiting microbes also hijack the hormone-regulated immune signaling network to establish a prolonged mutualistic association, highlighting the central role of plant hormones in the regulation of plant growth and survival. Copyright © 2012 by Annual Reviews. All rights reserved.

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