Abstract: Plants sense changes in the external environment through a number of signaling pathways, then give rise to a series of signaling cascades, among these, phospholipid signaling pathway plays an important role. We obtained an EST05 sequence from the suppression subtractive library under salt stress in Chenopodium album. The expression changes under different abiotic stresses were analyzed by RT-PCR, the results showed that the expression level of EST05 increased under the abiotic stress. Then, the ORF sequence was obtained by 3′- and 5′-RACE method. Sequence analysis showed that it is highly homologous with the phosphoinositide 5-phosphatase gene in Ricinus communis, which was then named as CaP5P. Finally, CaP5P was overexpressed in Arabidopsis thaliana to verify its function. Transgenic Arabidopsis showed reduced tolerance to salt stress in seed germination and seedling growth, suggesting that CaP5P performed as a negative regulatory factor under stress. The preliminary result is expected to provide the reference for negative regulation component in phospholipid signaling pathway.

Key words: Chenopodium album, Phosphoinositide 5-phosphatase, stress response, negative regulatory factor, expression analysis