Cassava is a starch-storing root crop that is an important source of dietary energy in tropical regions of the world. Genetic improvement of cassava by breeding is hindered by late flowering and sparse flower production in lines that are needed as parents. To advance understanding of regulatory mechanisms in cassava, this work sought to identify and characterize homologs of the FLOWERING LOCUS T (FT) gene. Ten members of the phosphatidylethanolamine-binding protein gene family, to which FT belongs, were obtained from the cassava genome database. Phylogenetic and sequence analysis of these proteins was used to identify two putative FT homologs which had amino acid sequences at key positions in accordance with those predicted for functional FTs. Expression of these ten genes was determined in mature leaves, immature leaves, flower buds, fibrous roots, storage roots and stem. The FT transcripts were expressed in mature leaves, as expected for their possible role in leaf-to-apical meristem signaling. In growth chamber studies, plants flowered earlier in long-day photoperiod than in short-day photoperiod. Expression studies indicated that while MeFT1 was expressed in leaves without a clear-cut photoperiod response, MeFT2 was expressed in a photoperiod-dependent manner, consistent with its involvement in photoperiodic control of flowering. In growth chambers that subjected plants to a range of temperatures from 22 to 34 °C, flowering was delayed by warmer temperatures although MeFT1 and MeFT2 expression declined in only one genotype, indicating other factors regulate this response. The earliest flowering genotype, IBA980002, had high levels of MeFT1 and MeFT2 expression, suggesting that both homologs contribute to earliness of this genotype.

中文翻译：

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鉴定与木薯开花相关的光周期，温度和基因型的FT家族基因（Manihot esculenta，Crantz）。

木薯是一种储存淀粉的块根作物，是世界热带地区膳食能量的重要来源。由于育成的木薯的遗传改良受到作为父母需要的品系中开花较晚和花稀疏生产的阻碍。为了加深对木薯调节机制的了解，这项工作试图鉴定和表征“花LO”（FT）的同源物。）基因。从木薯基因组数据库中获得了FT所属的磷脂酰乙醇胺结合蛋白基因家族的10个成员。这些蛋白质的系统发生和序列分析被用来鉴定两个推定的FT同源物，这些同源物在关键位置具有与功能性FT预测的氨基酸序列相同的氨基酸序列。确定了这十个基因在成熟叶片，未成熟叶片，花蕾，纤维根，贮藏根和茎中的表达。FT转录本在成熟的叶子中表达，正如预期的那样，它们可能在叶子到顶端的分生组织信号传导中发挥作用。在生长室研究中，植物在长日照期比短日照期更早开花。表达研究表明，尽管MeFT1在叶片中表达而没有明确的光周期反应，MeFT2以光周期依赖性方式表达，与其参与开花的光周期控制一致。在使植物处于22至34°C温度范围内的生长室中，尽管MeFT1和MeFT2表达仅在一种基因型中下降，但温度升高导致开花延迟。最早的开花基因型IBA980002具有高水平的MeFT1和MeFT2表达，表明这两个同系物都有助于该基因型的早期性。表明其他因素调节了这种反应。最早的开花基因型IBA980002具有高水平的MeFT1和MeFT2表达，表明这两个同系物都有助于该基因型的早期性。表明其他因素调节了这种反应。最早的开花基因型IBA980002具有高水平的MeFT1和MeFT2表达，表明这两个同系物都有助于该基因型的早期性。