Abstract
To elucidate physiological roles of the TPC1 family, putative voltage-gated Ca2+ channels, we generated and characterized transgenic rice plants and cultured cells overexpressing OsTPC1 mRNA, as well as a retrotransposon-insertional knockout mutant. The overexpressing plants showed reduced growth and abnormal greening of roots. Growth of Ostpc1 seedlings was comparable to the control on agar plates, while significantly reduced in adult plants. These results suggest that OsTPC1 functions as a Ca2+-permeable channel involved in the regulation of growth and development. Cosuppression of NtTPC1s in apoaequorin-expressing BY-2 cells resulted in inhibition of [Ca2+]cyt rise in response to a fungal elicitor, while did not affect hypoosmotic shock-induced [Ca2+]cyt increase. Cosuppression of NtTPC1s also caused suppression of elicitor-induced PCD and defense-related gene expression. These results suggest that NtTPC1s are involved in Ca2+ mobilization induced by pathogenic elicitors, and have crucial roles in various stress-induced signal transduction pathways.
