Effect of phosphate starvation on CAPRICE homolog gene expression in the root of Arabidopsis.

Abstract

Phosphate (Pi) starvation affects root hair formation to increase the absorptive surface area of the roots. CAPRICE (CPC) and its homolog genes, including TRIPTYCHON (TRY), ENHANCER OF TRY AND CPC1 (ETC1), ETC2, and ETC3, positively regulate root hair formation in a partially redundant manner. In particular, ETC1 responds to Pi deficiency. To clarify role sharing among the CPC homolog genes under Pi-deficient condition, we analyzed the expression of five CPC homolog genes under Pi-deficient condition, using the real-time polymerase chain reaction analysis. Pi starvation enhanced the expression of not only ETC1, but also ETC3. Furthermore, ETC3, which is rarely expressed in the roots, was induced by Pi deficiency. The expression levels of CPC, TRY, and ETC2 in response to Pi deficiency were not significantly different from those under the control conditions. These results suggest that CPC homologs can be divided into two groups, genes that respond to Pi deficiency (ETC1 and ETC3) and those that do not (CPC, TRY, and ETC2).