Reference "Cell-Type Specificity of the Expression of Os BOR1, a Rice Efflux Boron Transporter Gene, Is Regulated in Response to Boron Availability for Efficient Boron Uptake and Xylem Loading"

Reference ID

11641

Title

Cell-Type Specificity of the Expression of Os BOR1, a Rice Efflux Boron Transporter Gene, Is Regulated in Response to Boron Availability for Efficient Boron Uptake and Xylem Loading

Source

The Plant cell, 2007, vol. , pp. -

Authors (6)

Nakagawa-Y	Hanaoka-H
Kobayashi-M	Miyoshi-K
Miwa-K	Fujiwara-T

Abstract

We describe a boron (B) transporter, Os BOR1, in rice (Oryza sativa). Os BOR1 is
a plasma membrane-localized efflux transporter of B and is required for normal
growth of rice plants under conditions of limited B supply (referred to as -B).
Disruption of Os BOR1 reduced B uptake and xylem loading of B. The accumulation
of Os BOR1 transcripts was higher in roots than that in shoots and was not
affected by B deprivation; however, Os BOR1 was detected in the roots of wild-
type plants under -B conditions, but not under normal conditions, suggesting
regulation of protein accumulation in response to B nutrition. Interestingly,
tissue specificity of Os BOR1 expression is affected by B treatment. Transgenic
rice plants containing an Os BOR1 promoter-beta-glucuronidase (GUS) fusion
construct grown with a normal B supply showed the strongest GUS activity in the
steles, whereas after 3 d of -B treatment, GUS activity was elevated in the
exodermis. After 6 d of -B treatment, GUS activity was again strong in the
stele. Our results demonstrate that Os BOR1 is required both for efficient B
uptake and for xylem loading of B. Possible roles of the temporal changes in tissue-
specific patterns of Os BOR1 expression in response to B condition are
discussed.