摘要
The rice （Oryza sativa L.） genome contains at least six genes exclusively with an SPX （SYG1/PHO81/XPR1） domain at the N-terminal, designated as OsSPX1-6. Here we report the diverse expression patterns of the OsSPX genes in different tissues and their responses to Pi-starvation. Among them, five genes, OsSPX1, 2, 3, 5 and 6 are responsive to Pi-starvation in shoots and/or in roots. The subcellular localization analysis indicates that OsSPX1 and OsSPX2 is exclusively located in nucleus, OsSPX3 in the cytoplasm, and OsSPX4 is a membrane localization protein. OsSPXI regulates OsSPX2, 3 and 5 at the transcription level and is positively involved in the responses of the genes to Pi-starvation. Overexpression of OsSPX3 downregulates OsSPX5 in shoots under Pi-sufficiency. OsSPX3 negatively regulates the PSI （Pi-starvation induced） gene, OslPS1 and is involved in the responses of miR399 and OsPH02 to Pi-starvation. Our results suggest that OsSPX1 may be a regulator involved in the transcriptions of OsSPX2, 3 and 5. OsSPX3 plays a role in OslPSllmiR399 mediated long distance regulation on OsPH02. Our results also indicate that OsSPX3 is involved in plant tolerance to Pi-starvation stress.
The rice （Oryza sativa L.） genome contains at least six genes exclusively with an SPX （SYG1/PHO81/XPR1） domain at the N-terminal, designated as OsSPX1-6. Here we report the diverse expression patterns of the OsSPX genes in different tissues and their responses to Pi-starvation. Among them, five genes, OsSPX1, 2, 3, 5 and 6 are responsive to Pi-starvation in shoots and/or in roots. The subcellular localization analysis indicates that OsSPX1 and OsSPX2 is exclusively located in nucleus, OsSPX3 in the cytoplasm, and OsSPX4 is a membrane localization protein. OsSPXI regulates OsSPX2, 3 and 5 at the transcription level and is positively involved in the responses of the genes to Pi-starvation. Overexpression of OsSPX3 downregulates OsSPX5 in shoots under Pi-sufficiency. OsSPX3 negatively regulates the PSI （Pi-starvation induced） gene, OslPS1 and is involved in the responses of miR399 and OsPH02 to Pi-starvation. Our results suggest that OsSPX1 may be a regulator involved in the transcriptions of OsSPX2, 3 and 5. OsSPX3 plays a role in OslPSllmiR399 mediated long distance regulation on OsPH02. Our results also indicate that OsSPX3 is involved in plant tolerance to Pi-starvation stress.
基金
Supported by the State Key Basic Research and Development Plan of China (2005CB120901)
Science and Technology Department of Zhejiang Province,China
