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Organ identity genes and modified patterns of flower development in Gerbera hybrida (Asteraceae)
Author(s) -
Yu Deyue,
Kotilainen Mika,
Pöllänen Eija,
Mehto Merja,
Elomaa Paula,
Helariutta Yrjö,
Albert Victor A.,
Teeri Teemu H.
Publication year - 1999
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1999.00351.x
Subject(s) - gerbera , biology , petal , inflorescence , mads box , asteraceae , botany , sepal , chrysanthemum morifolium , gene , genetics , arabidopsis , stamen , pollen , mutant
Summary We have usedGerbera hybrida(the cultivated ornamental, gerbera) to investigate the molecular basis of flower development in Asteraceae, a family of flowering plants that have heteromorphic flowers and specialized floral organs. Flowers of the same genotype may differ in a number of parameters, including sex expression, symmetry, sympetaly and pigmentation. In order to study the role of organ identity determination in these phenomena we isolated and functionally analysed six MADS box genes from gerbera; these were shown by phylogenetic analysis to be orthologous to well characterized regulatory genes described fromArabidopsisandAntirrhinum. Expression analysis suggests that the two gerberaagamousorthologues, theglobosaorthologue and one of thedeficiensorthologues may have functional equivalency to their counterparts, participating in the C and B functions, respectively. However, the function of a seconddeficiensorthologue appears unrelated to the B function, and that of asquamosaorthologue seems distinct fromsquamosaas well as from the A function. The induction patterns of gerbera MADS box genes conform spatiotemporally to the multi‐flowered, head‐like inflorescence typical of Asteraceae. Furthermore, gerbera plants transgenic for the newly isolated MADS box genes shed light onto the mechanistic basis for some floral characteristics that are typical for Asteraceae. We can conclude, therefore, that the pappus bristles are sepals highly modified for seed dispersal, and that organ abortion in the female marginal flowers is dependent upon organ identity and not organ position when position is homeotically altered.