Plant Breeding Institute, Christian-Albrechts-University of Kiel Kiel, Germany.
SESVanderHave N.V. Tienen, Belgium.
Front Plant Sci. 2014 Apr 14;5:146. doi: 10.3389/fpls.2014.00146. eCollection 2014.
Many plant species in temperate climate regions require vernalization over winter to initiate flowering. Flowering Locus C (FLC) and FLC-like genes are key regulators of vernalization requirement and growth habit in winter-annual and perennial Brassicaceae. In the biennial crop species Beta vulgaris ssp. vulgaris in the evolutionarily distant Caryophyllales clade of core eudicots growth habit and bolting time are controlled by the vernalization and photoperiod response gene BTC1 and the downstream BvFT1-BvFT2 module. B. vulgaris also contains a vernalization-responsive FLC homolog (BvFL1). Here, to further elucidate the regulation of vernalization response and growth habit in beet, we functionally characterized BvFL1 by RNAi and over-expression in transgenic plants. BvFL1 RNAi neither eliminated the requirement for vernalization of biennial beets nor had a major effect on bolting time after vernalization. Over-expression of BvFL1 resulted in a moderate late-bolting phenotype, with bolting after vernalization being delayed by approximately 1 week. By contrast, RNAi-induced down-regulation of the BvFT1-BvFT2 module led to a strong delay in bolting after vernalization by several weeks. The data demonstrate for the first time that an FLC homolog does not play a major role in the control of vernalization response in a dicot species outside the Brassicaceae.
许多温带气候地区的植物物种需要冬季春化才能开始开花。FLC 和 FLC 类基因是冬性一年生和多年生十字花科植物春化要求和生长习性的关键调节因子。在二年生作物物种糖甜菜亚种普通种中，生长习性和抽薹时间由春化和光周期响应基因 BTC1 和下游 BvFT1-BvFT2 模块控制。B. vulgaris 还含有一个春化响应的 FLC 同源物（BvFL1）。在这里，为了进一步阐明甜菜春化反应和生长习性的调控机制，我们通过 RNAi 和转基因植物中的过表达对 BvFL1 进行了功能表征。BvFL1 RNAi 既没有消除二年生甜菜对春化的需求，也没有对春化后抽薹时间产生重大影响。BvFL1 的过表达导致中度晚抽薹表型，春化后抽薹时间延迟约 1 周。相比之下，BvFT1-BvFT2 模块的 RNAi 诱导下调导致春化后抽薹时间延迟数周。这些数据首次表明，在十字花科以外的双子叶植物中，FLC 同源物在春化反应的控制中不起主要作用。
