ORCID Profile
0000-0001-9564-3057
Current Organisation
Queen's University
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Publisher: Springer Science and Business Media LLC
Date: 08-2005
DOI: 10.1007/S11103-005-8395-X
Abstract: Complex signal transduction pathways underlie the myriad plant responses to attack by pathogens. Ca(2+) is a universal second messenger in eukaryotes that modulates various signal transduction pathways through stimulus-specific changes in its intracellular concentration. Ca(2+)-binding proteins such as calmodulin (CaM) detect Ca(2+) signals and regulate downstream targets as part of a coordinated cellular response to a given stimulus. Here we report the characterization of a tomato gene (APR134) encoding a CaM-related protein that is induced in disease-resistant leaves in response to attack by Pseudomonas syringae pv. tomato. We show that suppression of APR134 gene expression in tomato (Solanum lycopersicum), using virus-induced gene silencing (VIGS), compromises the plant's immune response. We isolated APR134-like genes from Arabidopsis, termed CML42 and CML43, to investigate whether they serve a functionally similar role. Gene expression analysis revealed that CML43 is rapidly induced in disease-resistant Arabidopsis leaves following inoculation with Pseudomonas syringae pv. tomato. Overexpression of CML43 in Arabidopsis accelerated the hypersensitive response. Recombinant APR134, CML42, and CML43 proteins all bind Ca(2+ )in vitro. Collectively, our data support a role for CML43, and APR134 as important mediators of Ca(2+)-dependent signals during the plant immune response to bacterial pathogens.
Publisher: Springer Science and Business Media LLC
Date: 25-01-2018
DOI: 10.1007/S11103-018-0703-3
Abstract: We show that the calcium sensor, CML39, is important in various developmental processes from seeds to mature plants. This study bridges previous work on CML39 as a stress-induced gene and highlights the importance of calcium signalling in plant development. In addition to the evolutionarily-conserved Ca
Publisher: Wiley
Date: 04-11-2010
DOI: 10.1016/J.FEBSLET.2010.10.059
Abstract: Calmodulin(CaM)-regulated protein phosphorylation forms an important component of Ca(2+) signaling in animals but is less understood in plants. We have identified a CaM-binding receptor-like kinase from soybean nodules, GmCaMK1, a homolog of Arabidopsis CRLK1. We delineated the CaM-binding domain (CaMBD) of GmCaMK1 to a 24-residue region near the C-terminus, which overlaps with the kinase domain. We have demonstrated that GmCaMK1 binds CaM with high affinity in a Ca(2+)-dependent manner. We showed that GmCaMK1 is expressed broadly across tissues and is enriched in roots and developing nodules. Finally, we examined the CaMBDs of the five-member GmCaMK family in soybean, and orthologs present across taxa.
Publisher: Wiley
Date: 12-2007
Publisher: Elsevier BV
Date: 11-2009
Publisher: Portland Press Ltd.
Date: 10-12-2013
DOI: 10.1042/BJ20131080
Abstract: Many signalling pathways in plants are regulated by the second messenger calcium (Ca2+). In the standard model, Ca2+-sensor proteins, such as CaM (calmodulin), detect Ca2+ signals and subsequently regulate downstream targets to advance the signal transduction cascade. In addition to CaM, plants possess many CMLs (CaM-like proteins) that are predicted to function as Ca2+ sensors, but which remain largely uncharacterized. In the present study, we examined the biochemical properties, subcellular localization and tissue-specific distribution of Arabidopsis CML43. Our data indicate that CML43 displays characteristics typical of Ca2+ sensors, including high-affinity Ca2+ binding, conformational changes upon Ca2+ binding that expose hydrophobic regions and stabilization of structure in the presence of Mg2+ or Ca2+. In vivo localization analysis demonstrates that CML43 resides in cytosolic and nuclear compartments. Transgenic plants expressing a CML43:GUS (β-glucoronidase) promoter reporter gene revealed that CML43 promoter activity is restricted almost exclusively to root tips under normal growth conditions. GUS reporter activity in these transgenic plants was strongly increased when exposed to the defence compound SA (salicylic acid). Furthermore, immunoblot analysis revealed that the CML43 protein accumulates following treatment with SA. Collectively, our findings suggest that CML43 functions as a Ca2+ sensor in root tips during both normal growth and plant immune response.
No related grants have been discovered for Wayne Snedden.