Biology subjects

Lembinen, S.

Publications and source records attributed to Lembinen, S..

4 recordsLinked to original sources

bioRxiv2026

FvTFL1 reverses the function of FvGI-FvCO-FvFT1 pathway in the photoperiodic flowering of woodland strawberry

O_LIPhotoperiod is a stable seasonal signal. Although the photoperiodic flowering is well understood in short-day (SD) and long-day (LD) annual plants, regulatory mechanisms in perennials remain elusive. In a perennial woodland strawberry (Fragaria vesca L.), flowering is induced in SDs in autumn and plants flower following spring, while in plants with mutated FvTERMINAL FLOWER1 (FvTFL1), LDs induce flowering. C_LIO_LIWe investigated photoperiodic flowering of F. vesca through phenotypic and molecular characterization of transgenic lines and their crosses. We studied natural variation in flowering time and gene expression in European accessions, and explored their correlations with climatic, geographical and genetic origins. C_LIO_LIWe showed that FvGIGANTEA (FvGI) and FvCONSTANS (FvCO) activate FvFLOWERING LOCUS T1 (FvFT1) in LDs resulting in early flowering in fvtfl1 mutant, while in SD F. vesca, activation of FvTFL1 by FvFT1 reverses the photoperiodic requirement of flowering. In natural accessions, decreasing expression of FvFT1 and FvTFL1 towards colder climates in the east and north correlated with earlier flowering. C_LIO_LIWe define a photoperiodic flowering mechanism controlling floral transition of perennial F. vesca in autumn that differs from known mechanisms in annual and perennial plants. Our findings open new avenues to understand how perennial plants cope with changing seasons across climatic and geographical ranges. C_LI

plant biology↗

bioRxiv2025

FvFT1-FvTFL1 epistasis drives flowering time adaptation in woodland strawberry

Floral transition and flower bud development during autumn and winter are common in plants inhabiting temperate and cold climates. However, our understanding of the natural variation and underlying molecular mechanisms of such life-history strategy remain largely limited to Brassicaceae model species. To address this gap, we investigated flowering time variation across a broad geographical and bioclimatic range in Fragaria vesca (woodland strawberry), a perennial herb from the Rosaceae family. We found that the timing of floral transition and subsequent flowering in F. vesca populations is primarily shaped by population structure, reflecting postglacial colonization patterns from distinct refugia, and is further modulated by adaptations to winter temperatures. The association of increasing expression of FvFT1, the strawberry ortholog of FLOWERING LOCUS T, with delayed flowering in accessions from diverse climatic and genetic backgrounds suggested FvFT1 as a major candidate gene regulating flowering time variation. We further demonstrated how distinct florigen and antiflorigen roles of FvFT1 are dependent on functional alleles of F. vesca TERMINAL FLOWER1 (FvTFL1) and how the epistatic relationship between FvFT1 and FvTFL1 controls adaptive flowering time variation by adjusting sensitivity to floral inductive photoperiod and vernalization. Our findings reveal a major molecular basis of how timing of floral transition has adapted to temperature in a Rosaceae model inhabiting multiple climatic zones and highlight lineage-specific adaptive mechanisms underlying convergent life-history strategy. Significance statementMolecular mechanisms underlying flowering time adaptation have been primarily investigated in annual plants that transit to flowering in spring. However, many perennial plant species in temperate climates form flower buds in autumn and winter to flower in the following spring. We uncover wide geographical and climatic patterns of flowering time adaptation in the perennial model species woodland strawberry. We report that natural variation in the expression of strawberry FLOWERING LOCUS T (FvFT1) gene originating ice ages ago and further driven by local temperature adaptations control flowering time variation in this species. Finally, we show how FvFT1 may function as both flowering promoter and repressor depending on the genetic background, thus revealing a novel mechanism of flowering time adaptation.

plant biology↗

bioRxiv2024

Late Quaternary climatic impact on the woodland strawberry genome: a perennial herb's tale

Exploring a species paleohistory is crucial for understanding its responsiveness to climatic events, identifying drivers of adaptation, and developing effective biodiversity conservation strategies in the face of ongoing climate change. We analyzed 200 genomes of the perennial herb woodland strawberry (Fragaria vesca L.) from across Europe and investigated the population structure and demographic history of the species during past geoclimatic events. We found a clear division of populations into western and eastern genetic clusters, indicative of distinct glacial refugia and adaptations to variation in temperature seasonality. The eastern core populations were several times larger (defined as effective population size, NE) than populations in other regions, showed no evidence of inbreeding, and were resilient to several glacial maxima. However, we observed decreasing NE and higher inbreeding in populations toward range edges, particularly in the north, where these individuals went through bottlenecks during glaciations. Population divergence suggested that western and eastern Europe were colonized from separate refugia in multiple waves during the Holocene, while the largest current populations from the northern Mediterranean to southern regions of the Nordic countries formed a connected population chain with gene flow between eastern core populations and western Europe, primarily occurring through Central Europe. Similar patterns of colonization and hybridization may have occurred during past interglacial periods, contributing to the present-day population structure of woodland strawberry. We suggest that the unprecedented resolution of the species climatic history across six glacial-interglacial cycles presented here holds the promise of transforming the general understanding of species paleohistory through geoclimatically tracing ancestral haplotypes.

plant biology↗

bioRxiv2022

Diversity of the woodland strawberry inflorescences results from heterochrony antagonistically regulated by FvTFL1 and FvFT1

A vast variety of inflorescence architectures have formed during angiosperm evolution. Here we analyze the diversity and development of the woodland strawberry inflorescence. We show that it is a thyrse: a compound inflorescence in which the primary monopodial axis supports lateral sympodial branches, thus combining features of racemes and cymes. We demonstrate that this architecture is related to differences in the size and shape of the primary and lateral inflorescence meristems. We further show that woodland strawberry homologs of TERMINAL FLOWER 1 (TFL1) and FLOWERING LOCUS T (FT) antagonistically regulate the development of both the racemose and cymose components of the strawberry thyrse: the loss of functional FvTFL1 and overexpression of FvFT1 reduce the number and complexity of the cymose components, whereas silencing of FvFT1 has the opposite effect and can partially rescue the fvtfl1 mutation. We complement our experimental findings with a computational model, which captures the development of the woodland strawberry inflorescence using a small set of rules, and shows that its phenotypic diversity can be explained in terms of heterochrony resulting from the opposite action of FvTFL1 and FvFT1 on the progression from the branching to flowering state.

plant biology↗