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

• Published in: The Plant journal : for cell and molecular biology 2005-06, Vol.42 (6), p.798-809
• Main Authors: Kurusu, T, Yagala, T, Miyao, A, Hirochika, H, Kuchitsu, K
• Format: Article
• Language: English
• Subjects: Allium cepa; apoptosis; Aureobasidium pullulans; Biological and medical sciences; Biological Transport; Calcium - metabolism; calcium channels; Calcium Channels - physiology; calcium ion; Cell biochemistry; Cell Death - physiology; Cell physiology; cultured cells; disease resistance; elicitor; Endo-1,4-beta Xylanases; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Fungal Proteins; Gene Expression; gene overexpression; Generalities. Disease free stocks; grain crops; hypersensitive cell death; hypersensitive response; Hypocrea rufa; insertional mutagenesis; ion channel; mitogen-activated protein kinase; Mitogen-Activated Protein Kinases - metabolism; mitogen‐activated protein kinase activation; Mutagenesis, Insertional; onions; Oryza - physiology; Oryza sativa; oxidative burst; Phytopathology. Animal pests. Plant and forest protection; Plant physiology and development; plant proteins; Plant Proteins - genetics; Plant Proteins - metabolism; protein kinases; Reactive Oxygen Species; resistance mechanisms; retrotransposons; rice; Signal Transduction; transgenes; transgenic plants; Trichoderma - enzymology; xylanases
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2005.02415.x

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 Ca2+-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 Ca2+-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.