[The effects of phosphorus, glucose and cytokinin on SEN1 gene expression in Arabidopsis].
SEN1 is a senescence-associated gene in Arabidopsis which is strongly induced by phosphate (Pi) starvation. To investigate the interaction between Pi starvation induced regulation system and senescence-induced regulation system, SEN1 promoter-glucuronidase (GUS) chimeric gene was constructed into the pCAMBIA1391z plasmid. The promoter region of the SEN1 was investigated by PCR amplification. The expression of SEN1 gene in leaves was enhanced under nutrition stress (nitrogen, phosphate, and potassium starvation), but the expression of SEN1 gene in roots was induced only by phosphate starvation. SEN1 was induced in elongated hypocotyl in darkness, suggesting that SEN1 may involved in light-regulated hypocotyl elongation. Fluorometric assays of the GUS activity indicate that the expression of SEN1 induced by phosphate starvation was repressed by addition of glucose and cytokinin, which indicates that Pi-starvation signaling on SEN1 may overlap with the Pi-signaling on other Pi-starvation response genes. Expression of the SEN1 gene was also strongly induced in leaves and roots by 3% glucosamine, a inhibitor of glucose transporter under both Pi sufficient and deficient conditions, while cytokinin reduced the expression under Pi starvation condition, but not under Pi sufficient condition. The results provide clues that the up-regulated expression of SEN1 by glucosamine give rise to glucose limitation through a signaling pathway regulated by Pi starvation. The cis-acting elements distributed in the promoter of SEN1 has also been discussed.
Yu
Chao
C
College of Life Sciences, Zhejiang University, Hangzhou 310029, China.
Hou
Xing-Liang
XL
Wu
Ping
P
D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics*; D003583:Cytokinins / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D005947:Glucose / Q000494:pharmacology*; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism / Q000494:pharmacology*; D010758:Phosphorus / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics
D029681:Arabidopsis Proteins; D003583:Cytokinins; D010710:Phosphates; C098796:Sen1 protein, Arabidopsis; D010758:Phosphorus; D005966:Glucuronidase; D005947:Glucose