Molecular Basis of Structural Studies, Phytochemical Characterization and Nutritional Evaluation of New Modified Alfalfa (with "HB", "TT8" and "miR156" Genes) Developed through Gene Transformation and Gene Modification in Ruminant Livestock Systems

苜蓿（Medicago sativa L.）是世界上最重要的牧草之一。通过三种途径提高其营养品质：(1)通过基因转化和/或基因修饰使苜蓿产生最佳水平的原花青素；(2)通过改变复杂细胞壁生物合成途径改变木质素构象，降低木质素对养分有效性的影响；(3)修饰苯丙类生物合成途径还原紫花苜蓿复合细胞壁中羟基肉桂酸类化合物。*最近，三种新开发的基因修饰苜蓿基因型（“HB”，“TT8”和“miR156”基因）已经可用。预计这些基因可能导致原花青素的产生，影响木质素和羟基肉桂酸的生物合成途径，降低木质素和羟基肉桂酸的水平，并改变木质素在复杂细胞壁中的构象。反过来，这将有利于改变瘤胃降解动力学的程度，允许优化营养物质降解比，提高营养物质利用率，从而减少和预防腹胀和其他消化系统疾病。*该项目的目的是全面了解新的“HB”、“TT8”和“miR156”基因转化和基因修饰在分子基础上影响苜蓿的内在结构，以及复杂反刍动物系统中氮代谢、微生物氮积累、瘤胃微生物活性和氮利用效率。该项目将为紫花苜蓿超基因型的开发提供重要信息。一系列结合先进分子生物技术、同步加速器分子技术以及体外、体内和建模实验方法的实验将进行，以解决所述的假设和目标。高素质人员的培训将通过这一建议进行。这个研究项目被设计为适合硕士和博士学生的培训。*本研究将有助于我们全面了解影响紫花苜蓿内在分子结构、分子结构和复杂瘤胃系统中营养物质利用相互作用的基因转化和修饰。从长远来看，据估计（根据加拿大农业和农业食品部的一份报告），通过开发最终的苜蓿超级基因型，每年将为80 - 120亿美元的加拿大乳制品和肉牛行业节省20 - 24亿美元的成本。******

Alfalfa (Medicago sativa L.) is one of the most important forages in the world. Its nutritional quality can be improved through three approaches: (1) Gene-transformation and/or gene modification to make alfalfa produce an optimal level of proanthocynidins; (2) Modification of lignin conformation through changing biosynthesis pathway in complex cell wall to reduce lignin impact on nutrient availability; and (3) Modification of phenylpropanoid biosynthetic pathway to reduce hydroxycinnamic acid compounds in complex cell wall of alfalfa.*Recently, three newly developed gene-modified alfalfa genotypes ("HB", "TT8" and "miR156" genes) have became available. It is expected that these genes may result in producing proanthocynidins, affect lignin and hydroxycinnamic acid biosynthesis pathway and reduce lignin and hydroxycinnamic acid levels, and modify lignin conformation in complex cell wall. This should, in turn, benefit the degree of change in rumen degradation kinetics, allow for an optimized nutrient degradation ratio, improve nutrient availability and result in the reduction and prevention of bloat and other digestive disorders.*The objective of this program is to attain a comprehensive understanding of the new "HB", "TT8" and "miR156"gene transformation and gene modification that influence alfalfa's intrinsic structure on a molecular basis as well as nitrogen metabolism, microbial nitrogen accumulation, rumen microbial activity, and the efficiency of nitrogen utilization in complex ruminant systems. This project will provide important information to assist the development of super genotypes of alfalfa. A series of experiments combining advanced molecular biotechnology, synchrotron molecular techniques as well as in vitro, in vivo and modeling experimental approaches will be conducted to address the stated hypothesis and objectives. The training of Highly Qualified Personnel  (HQP) will take place through this proposal. This research program has been designed to be suitable for the training of both M.Sc. and Ph.D. students.*The proposed research will contribute significantly to our knowledge in a comprehensive understanding of the gene transformation and modification that influence alfalfa's intrinsic molecular structure, molecular structure and nutrient utilization interaction in complex rumen system. In the long-term, it is estimated (in a report by Agriculture and Agri-Food Canada) that a $2-4B annual cost savings will be realized for the $8-12B Canadian dairy and beef cattle industry through the development of final super genotypes of alfalfa.******