Plant Gene Engineering Center
The PGEC was formed in 2010 upon the arrival of David Ow. In 2012, the PGEC was merged into the newly formed Molecular Analysis & Genetic Improvement Center(MAGIC).
目前将多个转化基因整合到一个基因组的方法是通过传统育种手段，借助基因位点的重组获得。该手段可用于整合不同研究者在不同时间利用不同方法所转化的基因。该方法一个的缺点是随着转基因位点的增加，需要在越来越大的群体进行筛选，才能找到稀有的包含各个转基因位点和其他优良非转基因性状位点组合的个体。虽然将外源基因直接导入栽培种，可跳过由实验品系向栽培品系导入转基因的基因渗入过程，但是该方法仍需要向许多田间栽培品种分别导入目的基因，并要对每一次独立转化事件进行鉴定和申请许可。如果能减少分离的转基因位点，那么将大大简化随后的基因渗入过程。通过在一个位点同时导入多个基因可以达到上述目的，但该方法每次转化都需要重复导入以前的基因。假如可以不必重复转化那些已经转化的基因，而是在一个已经转化的基因位点上加入新的基因，这将是一个合理的策略。重组酶介导的特异性位点重组可以在已知的位点叠加新DNA(J Integ. Plant Biol. 53: 512-519)。我们课题组已经开始在水稻基因组中利用特异性位点基因叠加技术进行多基因转化研究。
Site-specific gene stacking
The current method for combining transgenes into a genome is through the assortment of independent loci, a classical operating system compatible to transgenic traits created by different developers, at different times and/or through different transformation techniques. The one drawback in this approach is that as the number of transgenic loci increases over time, increasingly larger populations are required to find the rare individual with the desired assortment of transgenic loci along with the non-transgenic elite traits. Introducing a transgene directly into a field cultivar would bypass the need to introgress the engineered trait. However, this necessitates separate transformations into numerous field cultivars, along with the characterization and regulatory approval of each independent transformation event. Reducing the number of segregating transgenic loci would greatly facilitate the downstream introgression process. This could be achieved if multiple traits are introduced at the same time, which would be preferred if each of the many traits is new or requires re-engineering. If the re-engineering of previously introduced traits is not needed, then appending a new trait to an existing locus would be a rational strategy. Recombinase mediated site-specific recombination can deliver new DNA into a known locus (J Integ. Plant Biol. 53: 512-519), and we have initiated a program to develop the site-specific stacking of transgenes into the rice genome.
环境胁迫导致作物减产，生物胁迫和非生物胁迫都会扰乱细胞代谢平衡，引起细胞内活性氧水平升高，进而导致细胞损伤和死亡。我们课题组的研究趣在于，解析植物在应答能引起氧化损伤的重金属胁迫过程中的分子机理。最近我们鉴定了拟南芥植物氧化胁迫基因oxidative stress tolerance 2 (OXS2)功能EMBO J. 30:3812-3822. 研究结果表明OXS2是胁迫逃逸途径中关键调节因子。胁迫逃逸途径是指植物在极端环境下，会提早进入生殖生长以保护物种生存的一种机制。胁迫环境下，OXS2蛋白从细胞质转移到细胞核进而激活开花代谢途径。这一研究成果的潜在应用价值，通过基因工程手段在作物中建立一个低敏感度的胁迫逃逸途径，从而降低逆境下胁迫逃逸发生的几率，避免提前开花造成减产。目前我们正在研究水稻中的OXS2基因。另外，我们也同时在研究其它几个氧化胁迫基因的功能。
Molecular biology of stress tolerance
Environmental stresses reduce plant productivity. Both abiotic and biotic stresses disrupt normal cellular homeostasis leading to elevated levels of reactive oxygen species, then in turn leads to cellular damage and cell death. We have been interested in the molecular mechanisms of plant tolerance to heavy metals that leads to oxidative stress. Recently, we have determined the molecular function of the Arabidopsis oxidative stress tolerance gene 2 (OXS2) EMBO J. 30:3812-3822. We found that it is a key regulator of stress escape: a survival mechanism in which during dire conditions plants enter early reproduction to insure species preservation. During stress, OXS2 protein relocates from the cytoplasm to the nucleus to activate the flowering pathway. The significance of this work may lie in the potential engineering of a less sensitive stress escape response in crop plants, as the early flowering caused by stress escape can reduce crop yield. Currently, we are extending the OXS2 study to rice. Additionally, we are also studying the function of several other oxidative stress tolerance genes.
Traditional agriculture spans horizontally across land and water. Extending farming vertically in urban skyscrapers is a new cncept that is fittingly attractive for China’s urbanization. By 2040, Chinese cities will house a billion residents, and the need to provide fresh food for this large population will be a constant challenge. Urban development reduces arable land for traditional agriculture while urban industrialization pushes clean growing areas further away from urban centers. Hence, not only is China facing the prospect of less capacity for food production, but also escalating costs for food transport and packaging, since these are limited by petroleum availability. In vertical agriculture, much of the land displaced by urban sprawl and environmental degradation can regain agricultural productivity. Locally grown vegetables would save otherwise costly handling, packaging and transport that is dependent on fossil fuel. Water and fertilizers are more efficient in closed hydroponics systems without causing eutrophication of scarce drinking water supplies. Herbicides are not necessary, and pesticides substantially reduced. Hydroponically grown vegetables could be healthier given the soil-grown counterparts given the high soil pollution near most urban surrounds. Augmenting traditional farming with vertical farming could increase overall food production, and with a steady source not as subjected to the whim of weather. As importantly, vegetable gardens add aesthetic value to concrete-laden cities, and may even improve temperature and air quality. We are currently exploring the use of urban roofs for vertical agriculture. This past year, we have constructed a roof greenhouse to experiment with various production methods in growing fresh vegetables within an urban center.