Browsing by Author "Meier, Stuart"

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    The arabidopsis wall associated kinase-like 10 gene encodes a functional guanylyl cyclase and is coexpressed with pathogen defense related genes
    (Public Library of Science, 2010) Meier, Stuart; Ruzvidzo, Oziniel; Morse, Monique
    Second messengers have a key role in linking environmental stimuli to physiological responses. One such messenger, guanosine 3′,5′-cyclic monophosphate (cGMP), has long been known to be an essential signaling molecule in many different physiological processes in higher plants, including biotic stress responses. To date, however, the guanylyl cyclase (GC) enzymes that catalyze the formation of cGMP from GTP have largely remained elusive in higher plants. We have identified an Arabidopsis receptor type wall associated kinase–like molecule (AtWAKL10) as a candidate GC and provide experimental evidence to show that the intracellular domain of AtWAKL10431–700 can generate cGMP in vitro. Further, we also demonstrate that the molecule has kinase activity indicating that AtWAKL10 is a twin-domain catalytic protein. A co-expression and stimulus-specific expression analysis revealed that AtWAKL10 is consistently co-expressed with well characterized pathogen defense related genes and along with these genes is induced early and sharply in response to a range of pathogens and their elicitors.
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    Ozone and nitric oxide induce cGMP-dependent and independent transcription of defence genes in tobacco
    (Wiley, 2009) Pasqualini, Stefania; Meier, Stuart; Gehring, Chris
    Here, we analyse the temporal signatures of ozone (O3)-induced hydrogen peroxide (H2O2) and nitric oxide (NO) and the role of the second messenger guanosine 3′,5′-cyclic monophosphate (cGMP) in transcriptional changes of genes diagnostic for biotic and abiotic stress responses. Within 90 min O3 induced H2O2 and NO peaks and we demonstrate that NO donors cause rapid H2O2 accumulation in tobacco (Nicotiana tabacum) leaf. Ozone also causes highly significant, late (> 2 h) and sustained cGMP increases, suggesting that the second messenger may not be required in all early (< 2 h) responses to O3, but is essential and sufficient for the induction of some O3-dependent pathways.