SrPEPC, a Sesbania rostrata phosphoenolpyruvate carboxylase gene, is expressed in both phosphate-deficient roots and effective nodules

Abstract

Previously, we cloned a full-length cDNA (SrPEPC) corresponding to ‘Pi-deficiency-inducible PEPC’ from Sesbania rostrata. In this study, we analyzed the expression of SrPEPC in roots and nodules to examine the tissue specificity of SrPEPC. The transcript levels of SrPEPC were high in the stem- and root-nodules of nodulated plants, as well as in the roots of Pi-deficient plants. These results suggest that SrPEPC may function as a nodule-enhanced PEPC in addition to a ‘Pi-deficiency-inducible PEPC.’ When the plants forming stemnodules were transferred to Pi-deficient conditions, the transcript levels of SrPEPC in the stem-nodules had decreased. Furthermore, when Pi supply to the plants was resumed after Pi-deficiency, the expression of SrPEPC in the stem-nodules had returned to a high level. These results suggest that the regulation of the expression of SrPEPC in the nodules is different from that in the roots by Pi-deficiency.

Key Words:

• nodulation
• phosphate deficiency
• phosphoenolpyruvate carboxylase
• Sesbania rostrata