Hormone and sugar effects on rice sucrose transporter OsSUT1 expression in germinating embryos
Journal
Acta Physiologiae Plantarum
Journal Volume
32
Journal Issue
4
Pages
749-756
ISSN
0137-5881
Date Issued
2010-01-12
Author(s)
Abstract
The rice (Oryza sativa L.) OsSUT1 gene encodes a sucrose transporter protein. OsSUT1 was suggested to contribute to phloem loading of sucrose. OsSUT1 expression is highly induced in embryos after seeds were imbibed in water and peaked at 2 days after imbibition, but mRNA levels decline gradually afterwards. In this study, we demonstrated that phytohormones and sugars regulate OsSUT1 expression. Antagonism of abscisic acid and gibberellic acid appeared to play an important role in regulating OsSUT1 expression during embryo germination. In addition, our data showed a glucose and sucrose effect on OsSUT1 expression that represented a bi-phase process. Initially, glucose and sucrose functioned as negative regulators of OsSUT1 expression in germinating embryos after a 1-day treatment; however, when the treatment duration was extended to 5 days, OsSUT1 expression was significantly enhanced. Therefore, we hypothesized that the glucose and sucrose effect might occur in combination with other side effects, such as changes in hormone content or catabolism. Based on the effects that sugar analogs have on OsSUT1 expression, we suggest that the signal transduction for regulating glucose-responsive OsSUT1 expression in embryos occurs via a hexokinase-mediated pathway. © 2010 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.
Subjects
Embryos
Rice
Seed germination
Sucrose transporter
Type
journal article