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First published online January 2, 2003; 10.1104/pp.010132 Plant Physiol, January 2003, Vol. 131, pp. 186-197 Regulation of Early Tomato Fruit Development by the Diageotropica Gene1Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331-2902
The vegetative phenotype of the auxin-resistant
diageotropica (dgt) mutant of tomato
(Lycopersicon esculentum Mill.) includes reduced
gravitropic response, shortened internodes, lack of lateral roots, and retarded vascular development. Here, we report that early
fruit development is also dramatically altered by the single-gene dgt lesion. Fruit weight, fruit set, and numbers of
locules and seeds are reduced in dgt. In addition, time
to flowering and time from anthesis to the onset of fruit ripening are
increased by the dgt lesion, whereas ripening is normal.
The dgt mutation appears to affect only the early stages
of fruit development, irrespective of allele or genetic background.
Expression of members of the LeACS
(1-aminocyclopropane-1-carboxylic acid synthase, a key regulatory enzyme of ethylene biosynthesis) and LeIAA
(Aux/IAA, auxin-responsive) gene families were
quantified via real-time reverse transcriptase-polymerase chain
reaction in both dgt and wild-type fruits, providing the first analysis of Aux/IAA gene expression in fruit. The
dgt lesion affects the expression of only certain
members of both the LeACS and LeIAA
multigene families. Different subsets of LeIAA gene family members are affected by the dgt mutation in
fruits and hypocotyls, indicating that the DGT gene product functions
in a developmentally specific manner. The differential expression of
subsets of LeIAA and LeACS gene family
members as well as the alterations in dgt fruit
morphology and growth suggest that the early stages of fruit
development in tomato are regulated, at least in part, by auxin- and
ethylene-mediated gene expression.
1 This work was supported by the National Science Foundation Integrative Plant Biology Program. V.B. was supported by a Fulbright fellowship. * Corresponding author; e-mail terri.lomax{at}oregonstate.edu; fax 541-737-3573. © 2003 American Society of Plant Biologists |
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