Publication details

Molecular analysis of FRI (FRIGIDA) gene in early and late-flowering ecotypes and late-flowering mutants in Arabidopsis thaliana.



Year of publication 2005
Type Article in Proceedings
Conference From laboratory to business
MU Faculty or unit

Faculty of Science

Field Genetics and molecular biology
Keywords Arabidopsis; late-flowering; FRI
Description Flowering time is stimulated by both environmental (light, temperature) and endogenous signals. FLC and FRI genes are the most important endogenous signals controlling onset of flowering in natural populations. FLC is a significant flowering repressor that is under the control of the FRI gene. Interaction between of both genes is reason of lateness in natural populations. In the FRI gene two frequent deletions are known, Ler- and Col-type deletions, which are responsible for early-flowering phenotype. These deletions have been identified only in early-flowering plants but never in late-flowering therefore we focused on molecular analysis of FRI gene in late-flowering ecotypes from the Czech Republic (Je-4, Je-18, Je-27, Je-28 and Hod) and in four late-flowering mutants (dn, L4, Spi and M73). For this purpose we used five PCR primers that cover the complete sequence of FRI gene including the promoter. Deletions or insertions were detected by agarose or polyacrylamide gels. Some of the PCR fragments were also sequenced. We confirmed the promoter deletion in early-flowering ecotypes Ler, S96 and Di-G that are commonly used as standard laboratory lines and that represent the genetic backgrounds of our late-flowering mutants. Surprisingly, we found another larger deletions in the FRI promoter of two late-flowering ecotypes (Je-27 and Je-28) and small deletions or insertions in the rest of the analysed ecotypes (except Je-4). In all four late-flowering mutants we found large or small promoter deletions that were the same as in early-flowering ecotypes which represent the genetic background of the mutant (except mutant dn). In two late-flowering ecotypes (Je-27 and Je-28) we revealed new changes in the coding region of FRI gene such as deletion in the first exon, insertion in the first intron or the second exon. Promoter deletions in the FRI gene in early-flowering plants are connected with loss of function (basis of earliness) we therefore analysed FRI expression level by RT-PCR. We found that FRI is expressed in late-flowering plants but unexpectedly also in early-late flowering ecotypes. From these results we concluded that promoter deletions in FRI gene can occur not only in early but also in late-flowering genotypes (ecotypes or mutants) without any impact on FRI gene expression and timing of flowering.
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