Rontein Denis, Basset Gilles, Hanson Andrew D
Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611, USA.
Metab Eng. 2002 Jan;4(1):49-56. doi: 10.1006/mben.2001.0208.
Drought and salinity are among the worst scourges of agriculture. One effective mechanism to reduce damage from these stresses is the accumulation of high intracellular levels of osmoprotectant compounds. These compounds include proline, ectoine, betaines, polyols, and trehalose and have evolved in many different organisms. Since some crop plants have low levels of these osmoprotectants or none at all, engineering osmoprotectant biosynthesis pathways is a potential way to improve stress tolerance. First-generation engineering work--much of it with single genes--has successfully introduced osmoprotectant pathways into plants that lack them naturally, and this has often improved stress tolerance. However, the engineered osmoprotectant levels are generally low and the increases in tolerance commensurately small. To get beyond trace levels of osmoprotectants and marginal tolerance increments we need to use flux measurements to diagnose what limits osmoprotectant levels in engineered plants and to use iterative cycles of engineering to overcome these limitations.
干旱和盐碱化是农业面临的最严重灾害之一。减少这些胁迫造成损害的一种有效机制是在细胞内积累高水平的渗透保护化合物。这些化合物包括脯氨酸、依克多因、甜菜碱、多元醇和海藻糖，在许多不同的生物体中都有进化。由于一些作物植物中这些渗透保护剂的含量很低或根本没有，设计渗透保护剂生物合成途径是提高胁迫耐受性的一种潜在方法。第一代工程工作——其中大部分是针对单个基因——已成功地将渗透保护剂途径引入天然缺乏这些途径的植物中，这通常提高了胁迫耐受性。然而，工程化的渗透保护剂水平通常较低，耐受性的提高相应也较小。为了超越痕量水平的渗透保护剂和微小的耐受性增量，我们需要使用通量测量来诊断是什么限制了工程植物中渗透保护剂的水平，并利用迭代的工程循环来克服这些限制。
