Setor de Fisiologia Vegetal, Departamento de Biologia, Universidade Federal de Lavras Lavras, Brazil ; Department of Molecular and Cellular Biology, University of Guelph Guelph, ON, Canada.
Department of Molecular and Cellular Biology, University of Guelph Guelph, ON, Canada.
Front Plant Sci. 2014 May 26;5:221. doi: 10.3389/fpls.2014.00221. eCollection 2014.
Agriculturally important grasses such as rice, maize, and sugarcane are evolutionarily distant from Arabidopsis, yet some components of the floral induction process are highly conserved. Flowering in sugarcane is an important factor that negatively affects cane yield and reduces sugar/ethanol production from this important perennial bioenergy crop. Comparative studies have facilitated the identification and characterization of putative orthologs of key flowering time genes in sugarcane, a complex polyploid plant whose genome has yet to be sequenced completely. Using this approach we identified phosphatidylethanolamine-binding protein (PEBP) gene family members in sugarcane that are similar to the archetypical FT and TFL1 genes of Arabidopsis that play an essential role in controlling the transition from vegetative to reproductive growth. Expression analysis of ScTFL1, which falls into the TFL1-clade of floral repressors, showed transcripts in developing leaves surrounding the shoot apex but not at the apex itself. ScFT1 was detected in immature leaves and apical regions of vegetatively growing plants and, after the floral transition, expression also occurred in mature leaves. Ectopic over-expression of ScTFL1 in Arabidopsis caused delayed flowering in Arabidopsis, as might be expected for a gene related to TFL1. In addition, lines with the latest flowering phenotype exhibited aerial rosette formation. Unexpectedly, over-expression of ScFT1, which has greatest similarity to the florigen-encoding FT, also caused a delay in flowering. This preliminary analysis of divergent sugarcane FT and TFL1 gene family members from Saccharum spp. suggests that their expression patterns and roles in the floral transition has diverged from the predicted role of similar PEBP family members.
农业上重要的禾本科作物如水稻、玉米和甘蔗与拟南芥在进化上相距甚远，但花诱导过程的一些组成部分高度保守。甘蔗开花是一个重要的因素，它会对甘蔗产量产生负面影响，并降低这种重要的多年生生物能源作物的糖/乙醇产量。比较研究促进了甘蔗中关键开花时间基因的假定同源基因的鉴定和特征描述，甘蔗是一种复杂的多倍体植物，其基因组尚未完全测序。使用这种方法，我们在甘蔗中鉴定了类似于拟南芥典型的 FT 和 TFL1 基因的磷脂乙醇胺结合蛋白 (PEBP) 基因家族成员，它们在控制从营养生长到生殖生长的转变中起着重要作用。属于花抑制物 TFL1 类群的 ScTFL1 的表达分析显示，其转录本存在于发育中的叶片中，围绕着茎尖，但不在茎尖本身。ScFT1 在未成熟叶片和营养生长植物的顶端区域被检测到，在花诱导后，也在成熟叶片中表达。ScTFL1 在拟南芥中的异位过表达导致拟南芥开花延迟，这可能是与 TFL1 相关的基因的预期结果。此外，表现出最晚开花表型的系表现出空中莲座丛形成。出乎意料的是，与编码 FT 的 florigen 最相似的 ScFT1 的过表达也导致开花延迟。对来自甘蔗属的不同的甘蔗 FT 和 TFL1 基因家族成员的初步分析表明，它们的表达模式和在花诱导中的作用已经从类似的 PEBP 家族成员的预期作用中分化出来。
