Development of an early flowering system for poplar breeding and biosafety research

树种只有在长时间的幼龄期（营养期）后才会开花（繁殖期），这在一些树种中是相当可变的，持续到40年。较长的营养期阻碍了林木育种的发展。尽管在集中培育松树、杨树、桉树和其他一些分类群方面取得了实质性的育种进展，但森林树木的“栽培品种”仍然可以被认为是近乎“野生植物”，几乎没有任何作物驯化的标志。森林树木基因工程最有希望的前景之一可能是克服长时间的营养阶段。利用开花时间（FTi）和分生组织同源基因诱导树木早花的方法已经取得了成功。然而，目前已有的早花杨树系统往往存在许多缺陷，如生长受到干扰，小孢子发生受到干扰，以及对木材形成等其他发育过程产生意想不到的影响。本项目旨在建立一个更有效、更可靠的杨树诱导开花系统。早花期对林木育种和遗传控制生物安全研究具有重要意义。将使用FTi和花分生器官/器官识别基因的基因堆叠来测试几种方法。将对不同转基因品系的早花、生长性能和木材特性以及部分杨树FTi和分生组织/器官特性基因的表达进行评价。

Tree species produce flowers (reproductive phase) only after a prolonged juvenile phase (vegetative phase), which is quite variable lasting in some tree species until 40 years. The long vegetative phase has impeded the development of forest tree breeding. Even though substantial breeding progress has been made with intensively bred pines, poplars, eucalypts and a few other taxa, forest tree ‘cultivars’ can still be considered as nearly ‘wild plants’ with few if any of the hallmarks of crop domestication. Probably one of the most promising prospects offered by genetic engineering of forest trees is on overcoming the long vegetative phase. Several approaches have been successful on the induction of early flowering in trees using flowering time (FTi) and meristem identity genes. However, hitherto available early flowering poplar systems often show many drawbacks, like disturbed growth, microsporogenesis, and unexpected effects on other developmental processes like wood formation. This project aims to generate a more efficient and reliable system for the induction of flowering in poplar. Early flowering would be very valuable to forest tree breeding and biosafety research on genetic containment. Several approaches will be tested using gene stacking of FTi and flower meristen/organ identity genes. Early flowering, growth performance and wood properties of the different transgenic lines, as well as gene expression of selected poplar FTi and meristem/organ identity genes will be evaluated.