Poster: Reproductive Development
Abs #
459: Functional analysis of the maize FT/TFL homologs reveals potential players in the floral transition.
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Presenter: |
Danilevskaya, Olga , olga.danilevskaya@pioneer.com |
Authors | Danilevskaya, Olga (A) Hermon, Pedro (A) Shirbroun, David (A) Bruggemann, Ed (A) Muszynski, Michael (A) Ananiev, Evguenii (A) | | Affiliations: |
(A): Pioneer Hi-Bred International
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The transition from vegetative to reproductive growth is a critical point in plant development. Despite the importance of flowering time as a developmental process and agronomic trait, only one maize flowering gene, id1 (indeterminate-1), has been cloned. However, genetic pathways leading to the initiation of flowering are well defined in Arabidopsis. The Arabidopsis flowering genes FT (flowering locus T) and TFL (terminal flower) encode 23-kD proteins with similar structures, but antagonistic functions. FT promotes flowering, whereas TFL acts as a repressor. The FT/TFL proteins are evolutionarily conserved between dicots and monocots. Eight maize FT/TFL homologs were found in the Pioneer/DuPont maize EST (Expressed Sequencing Tags) database. Phylogenetic analysis placed six maize genes into the FT clade and two into the TFL clade. Electronic Northern and RT-PCR revealed different expression patterns of maize FT/TFL homologs. Both ZmTFL1 and ZmTFL2 are expressed in the shoot apical meristem during vegetative growth but not expressed in the reproductive meristem. This result is consistent with their possible roles as repressors of flowering. Conversely, only one maize FT homolog, ZmFT1, is expressed in the apical meristem just after the floral transition. Five other FT homologs show expression in different tissues. ZmFT1 transcripts are absent in the id1-m1 mutant, suggesting that ZmFT1 activation in the apical meristem during the floral transition requires Id1 function. ZmFT1 maps to the flowering QTL’s on chromosome 8. Our results suggest that ZmFT1 and ZmTFL1- ZmTFL2 are candidates for maize flowering genes with possible antagonistic functions like the Arabidopsis genes.
