The spread of transgenes and exotic germplasm from planted crops into wild or feral species is a difficult problem for public and regulatory acceptance of genetically engineered plants, particularly for wind-pollinated trees such as poplar. We report that overexpression of a poplar homolog of the floral repressor SHORT VEGETATIVE PHASE-LIKE (SVL), a homolog of the Arabidopsis MADS-box repressor SHORT VEGETATIVE PHASE (SVP), delayed the onset of flowering several years in three genotypes of field-grown transgenic poplars. Higher expression of SVL correlated with a delay in flowering onset and lower floral abundance, and did not cause morphologically obvious or statistically significant effects on leaf characteristics, tree form, or stem volume. Overexpression effects on reproductive and vegetative phenology in spring was modest and genotype-specific. Our results suggest that use of SVL and related floral repressors can be useful tools to enable a high level of containment for vegetatively propagated short-rotation woody energy or pulp crops.

中文翻译：

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杨树中短植物相状（SVL）的过度表达延迟了田间生长树木的开花期并减少了开花丰度

转基因植物和外来种质从种植作物传播到野生或野生物种是公众和监管机构接受转基因植物的难题，特别是对于杨树等风媒树木。我们报告了花抑制因子的杨树同系物的过度表达短植物相状（SVL）, 拟南芥 MADS-box 阻遏物的同源物短期植物阶段 (SVP)，在田间种植的转基因杨树的三种基因型中延迟了几年开花的开始。较高的表达SVL与开花开始延迟和花卉丰度降低相关，并且不会对叶片特征、树形或茎体积造成形态上明显或统计学上显着的影响。春季过度表达对生殖和营养物候的影响是适度的和基因型特异性的。我们的结果表明，使用SVL和相关的花卉阻遏物可能是有用的工具，可以对无性繁殖的短轮转木质能源或纸浆作物进行高水平的遏制。