AUTHOR=Guo Yuan , Hans Harloff , Christian Jung , Molina Carlos 

TITLE=Mutations in single FT- and TFL1-paralogs of rapeseed (Brassica napus L.) and their impact on flowering time and yield components

JOURNAL=Frontiers in Plant Science

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2014.00282

DOI=10.3389/fpls.2014.00282

ISSN=1664-462X

ABSTRACT=<p>Rapeseed (<italic>Brassica napus</italic> L.) is grown in different geographical regions of the world. It is adapted to different environments by modification of flowering time and requirement for cold. A broad variation exists from very early-flowering spring-type to late-flowering winter cultivars which only flower after exposure to an extended cold period. <italic>B. napus</italic> is an allopolyploid species which resulted from the hybridization between <italic>B. rapa</italic> and <italic>B. oleracea</italic>. In <italic>Arabidopsis thaliana</italic>, the PEBP-domain genes <italic>FLOWERING LOCUS-T (FT)</italic> and <italic>TERMINAL FLOWER-1 (TFL1)</italic> are important integrators of different flowering pathways. Six <italic>FT</italic> and four <italic>TFL1</italic> paralogs have been identified in <italic>B. napus</italic>. However, their role in flowering time control is unknown. We identified EMS mutants of the <italic>B. napus</italic> winter-type inbreed line Express 617. In total, 103 mutant alleles have been determined for <italic>BnC6FTb, BnC6FTa</italic>, and <italic>BnTFL1-2</italic> paralogs. We chose three non-sense and 15 missense mutant lines (M<sub>3</sub>) which were grown in the greenhouse. Although only two out of 6 <italic>FT</italic> paralogs were mutated, 6 out of 8 <italic>BnC6FTb</italic> mutant lines flowered later as the control, whereas all five <italic>BnC6FTa</italic> mutant lines started flowering as the non-mutated parent. Mutations within the <italic>BnTFL1-2</italic> paralog had no large effects on flowering time but on yield components. F<sub>1</sub> hybrids between <italic>BnTFL1-2</italic> mutants and non-mutated parents had increased seed number per pod and total seeds per plant suggesting that heterozygous mutations in a <italic>TFL1</italic> paralog may impact heterosis in rapeseed. We demonstrate that single point-mutations <italic>in BnFT</italic> and <italic>BnTFL1</italic> paralogs have effects on flowering time despite the redundancy of the rapeseed genome. Moreover, our results suggest pleiotropic effects of <italic>BnTFL1</italic> paralogs beyond the regulation of flowering time.</p>