Arabidopsis transcriptional response to extracellular Ca2+ depletion involves a transient rise in cytosolic Ca2+.
Ecological evidence indicates a worldwide trend of dramatically decreased soil Ca(2+) levels caused by increased acid deposition and massive timber harvesting. Little is known about the genetic and cellular mechanism of plants' responses to Ca(2+) depletion. In this study, transcriptional profiling analysis helped identify multiple extracellular Ca(2+) ([Ca(2+) ]ext ) depletion-responsive genes in Arabidopsis thaliana L., many of which are involved in response to other environmental stresses. Interestingly, a group of genes encoding putative cytosolic Ca(2+) ([Ca(2+) ]cyt ) sensors were significantly upregulated, implying that [Ca(2+) ]cyt has a role in sensing [Ca(2+) ]ext depletion. Consistent with this observation, [Ca(2+) ]ext depletion stimulated a transient rise in [Ca(2+) ]cyt that was negatively influenced by [K(+) ]ext , suggesting the involvement of a membrane potential-sensitive component. The [Ca(2+) ]cyt response to [Ca(2+) ]ext depletion was significantly desensitized after the initial treatment, which is typical of a receptor-mediated signaling event. The response was insensitive to an animal Ca(2+) sensor antagonist, but was suppressed by neomycin, an inhibitor of phospholipase C. Gd(3+) , an inhibitor of Ca(2+) channels, suppressed the [Ca(2+) ]ext -triggered rise in [Ca(2+) ]cyt and downstream changes in gene expression. Taken together, this study demonstrates that [Ca(2+) ]cyt plays an important role in the putative receptor-mediated cellular and transcriptional response to [Ca(2+) ]ext depletion of plant cells.
College of Life Sciences, Inner Mongolia University, Hohhot, 010021, China.
Jing
J
Wang
Tergel
T
Tergel
Jianhua
J
Chen
Ju
J
Yang
Yan
Y
Kang
Zhi
Z
Qi
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000235:genetics; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D006706:Homeostasis / Q000235:genetics; D008954:Models, Biological; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D059467:Transcriptome / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D014885:Waxes / Q000378:metabolism
D029681:Arabidopsis Proteins; D002121:Calcium Channel Blockers; D014885:Waxes; D002118:Calcium
Arabidopsis; aequorin; calcium depletion; cytosolic calcium; transcriptional response