Developmental and stimulus-induced expression patterns of Arabidopsis calmodulin-like genes CML37, CML38 and CML39
2007
Vanderbeld, Barbara | Snedden, Wayne A
Various aspects of plant development and stress physiology are mediated by Ca²⁺ signaling. Ca²⁺ sensors, such as calmodulin, detect these signals and direct downstream signaling pathways by binding and activating diverse targets. Plants possess many unique, putative Ca²⁺ sensors, including a large family (50 in Arabidopsis) of calmodulin-like proteins termed CMLs. Some of these CMLs have been implicated in Ca²⁺-based stress response but most remain unstudied. We generated transgenic plants expressing CML::GUS reporter genes for members of a subfamily of CMLs (CML37, CML38 and CML39) which allowed us to investigate their expression patterns in detail. We found that CML::GUS genes displayed unique tissue, cell-type, and temporal patterns of expression throughout normal development, particularly in the flower, and in response to a variety of stimuli, including biotic and abiotic stress, hormone and chemical treatments. Our findings are supported by semiquantitative reverse-transcription PCR as well as analyses of microarray databases. Analysis of purified, recombinant CMLs demonstrated their ability to bind Ca²⁺ in vitro. Collectively, our data suggest that these CMLs likely play important roles as sensors in Ca²⁺-mediated developmental and stress response pathways and provide a framework of spatial and temporal expression to direct future studies aimed at elucidating their physiological roles.
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