Unravelling a genetic network for bolting time regulation in Beta species to breed winter sugar beet

甜菜是一种两年生的植物，在长期寒冷中抽苔。因此，用冬季种植的甜菜进行田间生产是不可能的。然而，冬季甜菜可能是一种有趣的甜菜生产替代方案，因为它们具有更高的产量潜力。我们克隆了甜菜抽苔期调控的两个关键调控因子BTC1和BvBBX19。我们假设这两个基因共同调节下游靶标的表达，如BvFT1和BvFT2。我们将与优先计划的两个合作伙伴合作，研究这两个基因在甜菜中的功能以及转化拟南芥后的功能。过量表达BTC1的转基因甜菜像普通甜菜一样在越冬后开始抽苔。然而，带有BTc1拷贝的转基因甜菜通常不能抽出，可能是由于BTc1的协同抑制。这些结果为培育冬季甜菜提供了动力。我们将在两个BTC1高表达系杂交后产生低表达或不表达BTc1的杂交种。杂交甜菜将在气候室、温室(半田间条件)和田间过冬种植。在第二种方法中，我们将培育双隐性甜菜(btc1和bvbbx19)，并在冬季后严重延迟抽苔。这些甜菜可以在全球范围内种植，而不受法律限制，因为它们是非转基因的。此外，我们将在PP1530的框架下与另一个合作伙伴合作进行系统转录实验，在气候室的标准化条件下种植甜菜。

Sugar beet is a biennial species bolting after exposure to extended cold. Therefore, field production with winter grown beets is impossible. However, winter beets could be an interesting alternative for beet production due to their higher yield potential. We have cloned two key regulators for bolting time control in beet, BTC1 and BvBBX19. We assume that both genes jointly regulate the expression of downstream targets such as BvFT1 and BvFT2. We will study the function of both genes in beet and after transformation into Arabidopsis thaliana in collaboration with two partners from the priority program. Transgenic beets overexpressing BTC1 start bolting after winter like common sugar beet. However, transgenic beets with >1 BTC1 copy generally failed to bolt probably due to BTC1 cosuppression. These results provided an incentive to breed winter beets. We will produce hybrids with low or absent BTC1 expression after crossing two BTC1 overexpression lines. Hybrid beets will be grown over winter in the climate chamber, in a gauzehouse (semi field conditions) and in the field. In a second approach we will produce double recessive beets (btc1 and Bvbbx19) with severely delayed bolting after winter. Those beets could be grown worldwide without legal restrictions because they are non-transgenic. Moreover, we will collaborate in a phylotranscriptomics experiment with another partner in the frame of PP1530 to grow sugar beet under standardized conditions in the climate chamber.