SPP 1530: Flowering Time Control - from Natural Variation to Crop Improvement

PP-5: Fladung

Development of an early flowering system for poplar breeding and biosafety research

Fladung_earlyflowerPoplarDuring development, plants change from a juvenile to an adult phase of vegetative growth and from a reproductively incompetent to acompetent phase. Whereas annual plants have a one-year life cycle including flowering and senescence, tree species produce flowers only after several years of reproductive incompetence. This phase, which is quite variable lasting in some tree species until 40 years, has impeded the development of forest tree breeding. Even though substantial breeding progress has been made with intensively bred pines, poplars, eucalypts and a few other taxa, forest tree ‘cultivars’ can still be considered as nearly ‘wild plants’ with few if any of the hallmarks of crop domestication. Probably one of the most promising prospects offered by genetic engineering of forest trees is on overcoming their prolonged phase of reproductive incompetence. Several approaches have been successful on the induction of early flowering in trees using flowering time (FTi) and meristem identity genes. However, hitherto available early flowering poplar systems show some drawbacks, like disturbed growth and microsporogenesis.


This project aims to generate a more efficient and reliable flowering in poplar. Early flowering would be very valuable to forest tree breeding and biosafety research on genetic containment. Several approaches will be tested using gene stacking of FTi and flower meristem/organ identity genes. Early flowering and growth performance of the different transgenic lines, as well as gene expression of selected poplar FTi and meristem/organ identity genes will be evaluated.

Project-related publications:

Pakull B, Kersten B, Lueneburg J, Fladung M (2014). A simple PCR-based marker to determine sex in aspen. Plant Biol (Stuttg), in press.

Ahuja MR, Fladung M (2014). Integration and inheritance of transgenes in crop plants and trees. Tree Genetics & Genomes, in press.

Kersten B, Pakull B, Groppe K, Lueneburg J, Fladung M (2014). The sex-linked region in Populus tremuloides Turesson 141 corresponds to a pericentromeric region of about two million base pairs on P. trichocarpa chromosome 19. Plant Biol (Stuttg) 16(2):411-41

Fladung M, Hoenicka H, Raj Ahuja M (2013). Genomic stability and long-term transgene expression in poplar. Transgenic Res 22(6):1167-78

Schroeder H, Hoeltken AM, Fladung M (2012). Differentiation of Populus species using chloroplast single nucleotide polymorphism (SNP) markers - essential for comprehensible and reliable poplar breeding. Plant Biol. 14: 374-381.

Hoenicka H, Lautner S, Klingberg A, Koch G, El-Sherif F, Lehnhardt D, Zhang B, Burgert I, Odermatt J, Melzer S, Fromm J, Fladung M (2012). Influence of over-expression of the Flowering Promoting Factor 1 gene (FPF1) from Arabidopsis on wood formation in hybrid poplar (Populus tremula L. x Populus tremuloides Michx.). Planta 235: 359-373

Fladung M, Polak O (2012). Ac/Ds-transposon activation tagging in poplar: a powerful tool for gene discovery. BMC Genomics 13:61

Fladung M, Altosaar I, Bartsch D, Baucher M, Boscaleri, F, Gallardo F, Haggman H, Hoenicka H, Nielsen K, Paffetti D, Seguin A, Stotzky G, Vettori C (2012). European discussion forum on transgenic tree biosafety. Nature Biotechnology 30 (1):37-38

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