Producing mimosine-free Leucaena leucocephala through metabolic pathway engineering

通过代谢途径工程生产不含含羞草碱的银合欢

• 批准号: 0827057
• 负责人: Dulal Borthakur
• 金额: $ 27.21万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-10-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0827057&HistoricalAwards=false
• 关键词: Producing; mimosine; free; Leucaena; leucocephala

CBET-0827057BorthakurThe Principal Investigators (PIs) seek to develop, through metabolic pathway engineering, a mimosine-free leucaena that can be used as a fodder without any harmful side effects to animals. Leucaena leucocephala (leucaena) is an important leguminous tree for agro-forestry in many tropical and subtropical countries. Leucaena is known as "the alfalfa of the tropics" since the high protein content of its foliage is comparable to that of alfalfa. However, leucaena plants contain a toxin, mimosine, which is harmful to animals. Producing mimosine-free leucaena is a challenging task because the biosynthetic pathway for mimosine is unknown and leucaena is recalcitrant to transformation. A novel metabolic engineering strategy will be used for removing mimosine from leucaena by introducing genes from its bacterial symbiont. This project will use two Rhizobium genes that are required for degradation of 3-hydroxy-4-pyridone (HP), which is a precursor for mimosine biosynthesis in leucaena. By expressing these genes in transgenic leucaena, the metabolic pathway for mimosine will be redirected to produce ammonia, pyruvate and formate, which should serve as additional nitrogen and carbon sources for the plant.This work will lead the way for neutralization of toxins in other legumes and non-legumes using metabolic engineering approaches. Hawaii is a prime location for testing bioengineered crops throughout the year, for which many scientists and trained technicians are needed. This project will help to create a group of scientists for the near future by training two graduate and six or more undergraduate students in biotechnology. Special efforts will be made to recruit the native Hawaiian and other Pacific Island students for training through this project. This project will also enhance biotechnology education in Hawaii by training 24 science teachers. Teachers will learn the latest developments in biotechnology, which will be then transmitted to the students. Biotechnology education is essential to stimulate interest of high school students to this rapidly growing technology. Without proper biotechnology education there is always a danger that the public may absorb negative publicity against biotechnology, transgenic crops, and their testing in Hawaii.

CBET-0827057Borthakur 首席研究员 (PI) 寻求通过代谢途径工程开发一种不含含羞草碱的银合欢，可用作饲料，对动物不会产生任何有害副作用。 银合欢 (银合欢) 是许多热带和亚热带国家重要的农林业豆科树种。银合欢被称为“热带苜蓿”，因为其叶子的蛋白质含量高，可与苜蓿相媲美。然而，银合欢植物含有一种毒素——含羞草碱，对动物有害。 生产不含含羞草碱的银合欢是一项具有挑战性的任务，因为含羞草碱的生物合成途径未知，而且银合欢难以转化。一种新的代谢工程策略将用于通过引入来自细菌共生体的基因来从银合欢中去除含羞草碱。该项目将使用降解 3-羟基-4-吡啶酮 (HP) 所需的两个根瘤菌基因，HP 是银合欢中含羞草碱生物合成的前体。通过在转基因银合欢中表达这些基因，含羞草碱的代谢途径将被重新定向以产生氨、丙酮酸和甲酸，这应作为植物的额外氮源和碳源。这项工作将为利用代谢工程方法中和其他豆科植物和非豆科植物中的毒素开辟道路。夏威夷是全年测试生物工程作物的黄金地点，需要许多科学家和训练有素的技术人员。该项目将通过培训两名生物技术研究生和六名或更多本科生，帮助在不久的将来培养一批科学家。将特别努力招募夏威夷本土和其他太平洋岛屿学生通过该项目进行培训。该项目还将通过培训 24 名科学教师来加强夏威夷的生物技术教育。教师将了解生物技术的最新发展，然后将其传授给学生。生物技术教育对于激发高中生对这种快速发展的技术的兴趣至关重要。如果没有适当的生物技术教育，公众可能会吸收针对生物技术、转基因作物及其在夏威夷进行的测试的负面宣传。