Roles of a Putative Voltage-Gated Ca²⁺-Permeable Channel, OsTPC1, in the Regulation of Elicitor-Induced Gene Expression and Defense Responses in Cultured Rice Cells.

Abstract

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. We identified a putative voltage-gated Ca²⁺-permeable channel (OsTPC1) in rice, and developed its overexperssors as well as its retrotransposon-insertional functional knockout mutant (Ostpc1). OsTPC1 has been suggested to determine sensitivity to a proteinaceous xylanase elicitor, TvX, and plays a role as a key regulator of TvX-induced defense responses including activation of a MAP kinase and hypersensitive cell death in suspension-cultured cells (Plant J. 2005 42: 798-809). Oligomicroarray transcriptome analyses revealed that TvX-induced expression of genes including those related to defense responses and metabolism including phytoalexin biosynethesis were suppressed in Ostpc1, highlighting the role of OsTPC1 in defense signaling in cultured rice cells.