Plant Physiol, September 2002, Vol. 130, pp. 78-89
Effect of Regulated Overexpression of the MADS Domain Factor
AGL15 on Flower Senescence and Fruit Maturation1
Su-Chiung
Fang2 and
Donna E.
Fernandez*
Department of Botany, University of Wisconsin, 430 Lincoln Drive,
Madison, Wisconsin 53706-1381
We have examined the effect of regulated overexpression of AGL15, a
member of the MADS domain family of regulatory factors, on reproductive
tissues. Using molecular and physiological markers, we show that
constitutive overexpression of AGL15 in Arabidopsis leads to delay and
down-regulation of senescence programs in perianth organs and
developing fruits and alters the process of seed desiccation. Through
genetic crosses, we show that the rate of water loss in the maturing
seeds is dictated by the genetic composition and physiological state of
the maternal tissue, rather than the embryo. To define the
developmental time and/or place when senescence programs are most
affected by elevated AGL15 levels, we expressed AGL15 under the control
of various promoters. Expression during senescence or in abscission
zone cells did not produce delays in floral organ senescence or
abscission. Using a glucocorticoid-inducible expression system, we show
that an increase in AGL15 levels around the time of flower opening is
necessary to delay senescence and increase floral organ longevity.
1
This work was supported by the University
of Wisconsin (Madison) Graduate School, by the U.S. Department of
Agriculture-National Research Initiative Competitive Grants
Program (grant no. 96-35304-3699), and by the Department of
Energy/National Science Foundation/U.S. Department of
Agriculture Collaborative Program on Research in Plant Biology
(grant no. DBI 96-02222).
2
Present address: Section of Cell and Developmental
Biology, University of California-San Diego, 9500 Gilman Drive MC0349, La Jolla, CA 92093.
*
Corresponding author; e-mail dfernand{at}facstaff.wisc.edu; fax
608-262-7509.
© 2002 American Society of Plant Physiologists
