The FRUITFULL gene
(previously called AGL8) is closely related in sequence to the
flower meristem identity genes APETALA1 (AP1) and CAULIFLOWER,
although its expression pattern is quite distinct from these two genes. FUL
RNA is dramatically up-regulated upon the transition from vegetative
to reproductive development, where its expression is detected in cauline
leaves, stems, and in flowers and fruits. During flower and
fruit development, FUL RNA is detected at high levels in the
FUL RNA (red) is
detected at high levels in the inflorescence meristem beginning at around
the transition to reproductive growth (left). Interestingly, FUL RNA
is absent from stage 1 and stage 2 flower primordia as they arise on the
flanks of the inflorescence meristem. At around stage 3 of flower
development, FUL RNA begins to accumulate in the central region that will
later give rise to carpels. Later in flower and fruit development,
FUL RNA is restricted to the valves of the developing carpels, as seen by
the cross-section (right).
The most dramatic phenotype caused
by mutations in FUL is a failure of the fruit to elongate post
fertilization. Consistent with its expression pattern, ful-mutant
valve cells fail to grow and differentiate, indicating that FUL is
required to specify a valve cell identity.
Example of the premature bursting of a ful silique due to failure of the fruit to elongate.
|In addition, mutations in ful dramatically enhance the phenotype of ap1 cal double mutants. The “cauliflower” phenotype characteristic of ap1 cal double mutants is caused by a proliferation of inflorescence-like meristems. However, later in plant development, ap1 cal double mutants produce flowers and fruits. In contrast, the ful ap1 cal triple mutant never flowers and instead produces ‘leafy shoots’.||
ap1 cal double muants (left) and ap1 cal ful triple mutant (right)
Mandel, A.M. and Yanofsky, M.F. (1995) The Arabidopsis AGL8 MADS-box gene is expressed in inflorescence meristems and is negatively regulated by APETALA1. Plant Cell 7:1763-1771.
Ferrandiz C, Gu Q, Martienssen R, Yanofsky M.F. (2000) Redundant regulation of meristem identity and plant architecture by FRUITFULL, APETALA1 and CAULIFLOWER. Development 127, 725-734
Gu Q, Ferrandiz C, Yanofsky M.F.,
Martienssen R (1998) The
FRUITFULL MADS-box gene mediates cell differentiation during Arabidopsis
fruit development. Development 125, 1509-1517 (1998)