Regulation of OsSPX1 and OsSPX3 on expression of OsSPX domain genes and Pi-starvation signaling in rice.
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. OsSPX1 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, OsIPS1 and is involved in the responses of miR399 and OsPHO2 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 OsIPS1/miR399 mediated long distance regulation on OsPHO2. Our results also indicate that OsSPX3 is involved in plant tolerance to Pi-starvation stress.
Wang
Zhiye
Z
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Hu
Han
H
Huang
Hongjie
H
Duan
Ke
K
Wu
Zhongchang
Z
Wu
Ping
P
D000595:Amino Acid Sequence; D015536:Down-Regulation / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D035683:MicroRNAs / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D012275:Oryza / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D010710:Phosphates / Q000172:deficiency* / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D014158:Transcription, Genetic
D035683:MicroRNAs; D010710:Phosphates; D010940:Plant Proteins; D012333:RNA, Messenger