Identification of a putative voltage-gated Ca2+ channel as a key regulator of elicitor-induced hypersensitive cell death and mitogen-activated protein kinase activation in rice.
Elicitor-triggered transient membrane potential changes and Ca2+ influx through the plasma membrane are thought to be important during defense signaling in plants. However, the molecular bases for the Ca2+ influx and its regulation remain largely unknown. Here we tested effects of overexpression as well as retrotransposon (Tos17)-insertional mutagenesis of the rice two-pore channel 1 (OsTPC1), a putative voltage-gated Ca(2+)-permeable channel, on a proteinaceous fungal elicitor-induced defense responses in rice cells. The overexpressor showed enhanced sensitivity to the elicitor to induce oxidative burst, activation of a mitogen-activated protein kinase (MAPK), OsMPK2, as well as hypersensitive cell death. On the contrary, a series of defense responses including the cell death and activation of the MAPK were severely suppressed in the insertional mutant, which was complemented by overexpression of the wild-type gene. These results suggest that the putative Ca(2+)-permeable channel determines sensitivity to the elicitor and plays a role as a key regulator of elicitor-induced defense responses, activation of MAPK cascade and hypersensitive cell death.
Kurusu
Takamitsu
T
Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Yagala
Toshikazu
T
Miyao
Akio
A
Hirochika
Hirohiko
H
Kuchitsu
Kazuyuki
K
D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology*; D016923:Cell Death / Q000502:physiology*; D043364:Endo-1,4-beta Xylanases; D004789:Enzyme Activation; D005656:Fungal Proteins; D015870:Gene Expression; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D014242:Trichoderma / Q000201:enzymology
D015220:Calcium Channels; D005656:Fungal Proteins; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D020928:Mitogen-Activated Protein Kinases; D043364:Endo-1,4-beta Xylanases; D002118:Calcium