Isolation of LUMINIDEPENDENS: A Gene Involved in the Control of Flowering Time in Arabidopsis

Lee, Ilha; Aukerman, Milo J.; Gore, Sherrie L.; Lohman, Karin N.; Michaels, Scott D.; Weaver, Louis M.; John, Maliyakal E.; Feldmann, Kenneth A.; Amasino, Richard M.

doi:10.2307/3869676

Cited by 24 publications

(36 citation statements)

References 7 publications

(8 reference statements)

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“…Although several genes that are concerned with flowering have now been cloned (24)(25)(26), none of these functions within the vernalization-dependent pathway. Mutations that reduce the vernalization response recently have been identified (27), but the corresponding genes, which may encode steps of the vernalization-dependent pathway, have not been isolated.…”

Section: Discussionmentioning

confidence: 99%

DNA methylation and the promotion of flowering by vernalization

Finnegan

Genger

Kovac

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

207

119

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We have tested the hypothesis that the promotion of flowering by prolonged exposure to low temperatures Many plants growing at high latitudes require exposure, as germinating seeds or vegetatively growing plants, to prolonged periods at low temperatures (vernalization) before they will initiate flowering. This ensures that flowering will occur in the warm days of spring and summer, which are favorable for pollination and seed development. Whereas some plants have an absolute requirement for vernalization, others, such as the late-flowering ecotypes of Arabidopsis, show a facultative requirement for vernalization, and will eventually flower even in the absence of a cold treatment (for review see ref. 1). The phenomenon of vernalization was first described in the middle of the 19th century (Kleppart, cited in ref.2), but only recently has a hypothesis suggesting a molecular mechanism for the low-temperature promotion of flowering been proposed (3).The cold treatment is perceived by cells, mitotically active at the time of treatment; early flowering results when these cells, or their descendants, form the floral͞inflorescence meristem, indicating that the vernalization signal is inherited mitotically rather than being transmitted from ''vernalized cells'' to the apex (4, 5). The vernalization signal is not transmitted to sexual progeny (1). The perceived parallels between the inheritance of the vernalization signal and of DNA methylation patterns led to the hypothesis that the vernalization response, in Arabidopsis and other plants, is mediated by changes in DNA methylation (3). Specifically it was proposed that the cold treatment results in demethylation of the promoter region(s) and subsequent activation of a gene or genes critical for initiating reproductive development. Mitotic inheritance of the vernalization signal is consistent with clonal inheritance of DNA methylation patterns (6), but it is now known that, in plants, methylation patterns may not be reset between generations (7-9), suggesting that factors other than DNA methylation may be involved in resetting the vernalization signal.Treatment of plants with the demethylating agent, 5-azacytidine (5-azaC) resulted in early flowering (3, 10). This earlyflowering response was restricted to plants that normally respond to vernalization, including certain late-flowering ecotypes and mutants of Arabidopsis and winter wheat. Spring wheats and other late-flowering Arabidopsis mutants that are insensitive to vernalization did not develop an early-flowering phenotype after 5-azaC treatment. These observations suggest that this response was specific to the vernalization-dependent pathway to flowering (3, 10, 11) rather than being a nonspecific effect of the treatment.In addition to causing demethylation, 5-azaC is a general inhibitor of transcription (12), so it is possible that the promotion of flowering by 5-azaC resulted from effects other than demethylation of DNA. To discriminate between these possibilities we have used Arabidopsis plants in which meth...

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Section: Discussionmentioning

confidence: 99%

DNA methylation and the promotion of flowering by vernalization

Finnegan

Genger

Kovac

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

207

119

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“…Two of the genes that regulate FLC expression have been characterized. LD encodes a putative transcription factor (16) and may act directly to regulate FLC transcription. FCA encodes an RNA binding protein (21), which may regulate FLC at a posttranscriptional level.…”

Section: Conclusion: the Key Role Of Flc In The Initiation Of Floweringmentioning

confidence: 99%

The molecular basis of vernalization: The central role of FLOWERING LOCUS C ( FLC )

Sheldon

Rouse

Finnegan

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

538

261

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R ecently, we reported on a gene, FLOWERING LOCUS F (FLF), from Arabidopsis whose activity, as determined by steady-state mRNA levels, is correlated quantitatively with the period taken to initiate flowering (1). The FLF gene encodes a putative transcription factor of the MADS-box class, which, we concluded, acts as a repressor of floral induction. Genetic analyses of Arabidopsis ecotypes previously identified FLOW-ERING LOCUS C (FLC) as a semidominant repressor of floral induction (2-4). Because FLF has similar properties to FLC and maps to the same chromosomal region, the possibility arose that FLF and FLC are one and the same gene; this hypothesis has been confirmed by Michaels and Amasino (5). We suggest that the gene be referred to as FLC and the mutants flf-1 to flf-9 now be referred to as flc-11 to flc-19.In many plant species, flowering is promoted by a period of exposure to low temperature through a process known as vernalization. A number of the late-flowering mutants and ecotypes of Arabidopsis have a vernalization response. We found that the vernalization-responsive late-flowering mutants had a higher level of FLC transcript than was present in the wild types and, importantly, that the non-vernalization-responsive lateflowering mutants did not have increased FLC transcript levels. The vernalization-responsive ecotype C24, which is somewhat late-flowering, also has a high level of FLC transcript that is reduced by the low-temperature treatment (1). These observations suggested to us that FLC must be directly involved in the vernalization response.We have shown that reduction in the level of genomic methylation largely substitutes for the low-temperature treatment in promoting flowering (6-8), implicating a reduction in DNA methylation level as a component in the vernalization response. Early-flowering METHYLTRANSFERASE1 antisense plants, with a decreased level of genomic methylation, have a reduced level of FLC activity as compared with the nontransformed control (1). The correlation between FLC transcription and methylation levels implies that FLC is regulated by methylation status, but we are not able to say whether this is through an alteration of the methylation status of the FLC gene itself, or whether it involves other genes that regulate FLC expression.In this paper, we demonstrate that the FLC gene is involved directly in controlling the response to vernalization and more generally in the timing of the transition to the reproductive phase of development. We find that a reduction in FLC activity is a key component of the vernalization response in six late-flowering vernalization-responsive mutants and in the C24 and Pitztal ecotypes. The late-flowering mutants are mutated in genes that regulate the activity of the FLC gene. We further show that the quantitative responses in the promotion of flowering to various periods of exposure to low temperature are paralleled by the levels of FLC transcript, and that the changes observed at the transcriptional level are reflected in the level of the FLC pr...

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“…LD encodes a putative homeodomain protein, and although the LD transcript is expressed throughout the plant, it is most abundant in the shoot and root apices (Lee et al, 1994a;Aukerman and Amasino, 1996). FCA encodes a protein with RNA binding and protein-protein interaction domains (Macknight et al, 1997).…”

Section: Autonomous Promotion Pathwaymentioning

confidence: 99%