BackgroundPlants are frequently subjected to abiotic and biotic stresses, and WRKY proteins play a pivotal role in the response to such stress. OsWRKY11 is induced by pathogens, drought, and heat, suggesting a function in biotic and abiotic stress responses.ResultsThis study identified OsWRKY11, a member of WRKY group IIc. It is a transcriptional activator that localized to the nucleus. Ectopic expression of OsWRKY11 resulted in enhanced resistance to a bacterial pathogen, Xanthomonas oryzae pv. oryzae; resistance was compromised in transgenic lines under-expressing OsWRKY11. Ectopic expression of OsWRKY11 resulted in constitutive expression of defense-associated genes, whereas knock-down (kd) of OsWRKY11 reduced expression of defense-associated genes during pathogen attack, suggesting that OsWRKY11 activates defense responses. OsWRKY11 bound directly to the promoter of CHITINASE 2, a gene associated with defense, and activated its transcription. In addition, ectopic expression of OsWRKY11 enhanced tolerance to drought stress and induced constitutive expression of drought-responsive genes. Induction of drought-responsive genes was compromised in OsWRKY11-kd plants. OsWRKY11 also bound directly to the promoter of a drought-responsive gene, RAB21, activating its transcription. In addition, OsWRKY11 protein levels were controlled by the ubiquitin-proteasome system.ConclusionOsWRKY11 integrates plant responses to pathogens and abiotic stresses by positively modulating the expression of biotic and abiotic stress-related genes.Electronic supplementary materialThe online version of this article (10.1186/s12284-018-0199-0) contains supplementary material, which is available to authorized users.

Chemical sensing by cell-surface receptors to effect signal transduction is a ubiquitous biological event. Despite extensive structural biochemical study, detailed knowledge of how signal transduction occurs is largely lacking. We report herein a kinetic and receptor ͉ signal transduction ͉ infrared spectroscopy

In methicillin-resistant Staphylococcus aureus, β-lactam antibiotic resistance is mediated by the transmembrane protein BlaR1. The antibiotic-sensor domain BlaRS and the L2 loop of BlaR1 are on the membrane surface. We used NMR to investigate interactions between BlaRS and a water-soluble peptide from L2. This peptide binds BlaRS proximal to the antibiotic acylation site as an amphipathic helix. BlaRS acylation by penicillin G does not disrupt binding. These results suggest a signal transduction mechanism whereby the L2 helix, partially embedded in the membrane, propagates conformational changes caused by BlaRS acylation through the membrane via transmembrane segments, leading to antibiotic resistance.

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Methicillin-resistant Staphylococcus aureus (MRSA) has evolved two mechanisms for resistance to beta-lactam antibiotics. One is production of a beta-lactamase, and the other is that of penicillin-binding protein 2a (PBP 2a). The expression of these two proteins is regulated by the bla and mec operons, respectively. BlaR1 and MecR1 are beta-lactam sensor/signal transducer proteins, which experience acylation by beta-lactam antibiotics on the cell surface and transduce the signal into the cytoplasm. The C-terminal surface domain of MecR1 (MecRS) has been cloned, expressed, and purified to homogeneity. This protein has been characterized by documenting that it has a critical and unusual Nzeta-carboxylated lysine at position 394. Furthermore, the kinetics of interactions with beta-lactam antibiotics were evaluated, a process that entails conformational changes for the protein that might be critical for the signal transduction event. Kinetics of acylation of MecRS are suggestive that signal sensing may be the step where the two systems are substantially different from one another.