A new paradigm for regulation of de novo fatty acid synthesis in plants

该项目将提高我们对植物脂肪酸合成的理解，作为未来工程设计师油料种子开发新策略的重要一步。 植物油是食品、燃料和化学品的宝贵可再生资源。编码负责脂质合成的酶的基因已经被鉴定，但对这些基因的调控仍然知之甚少。 该项目将采用多学科方法来研究新发现的蛋白质在调节脂肪酸合成的关键早期步骤中的作用，从而控制总植物油的积累。该项目将为两名本科生（包括代表性不足的少数民族）和两名研究生（STEM职业）做准备。他们将接受植物生物技术，遗传学和蛋白质科学的现代研究方法的培训。来自南密西西比大学（USM;一个特别多样化的学生群体）的本科生将前往密苏里州大学（MU），与MU本科生一起在Thelen和货车Doren实验室为本科生进行为期9周的密集夏季研究体验。MU和USM的研究生将通过指导和科学交流的正式培训以及指导本科生的研究获得可转移的技能。本项目利用多学科团队的专业知识来验证新发现的生物素附着结构域（BADC）基因家族及其对应的生物素羧基载体蛋白（BCCP）共同作为分子变阻器来调节乙酰辅酶A羧化酶（ACCase）活性并最终调节种子油积累。定量生物物理分析将区分两种假说，BADC蛋白如何嵌入到全息ACCase复合物和降低酶活性。该分析将测试溶液中BADC结构的替代方案与其对BC亚基的亲和力，使BADC能够与其功能性催化兄弟蛋白BCCP竞争进入ACCase。BADC在种子发育和诱导的脂肪酸合成（FAS）调节期间的调节作用将通过在FAS的各种状态下定量相对于ACC酶的BADC调节蛋白的基因表达和绝对蛋白水平来表征。将通过调节BADC蛋白水平并通过ACCase和FAS量化碳通量以及对总油积累的影响来在植物中测试变阻器假设。此外，将测试BADC蛋白减轻FAS反馈抑制的能力，所述FAS反馈抑制在工程化以产生新型油的植物中诱导。这将澄清限制油籽工程的代谢瓶颈。

This project will enhance our understanding of fatty acid synthesis in plants as an important step in developing new strategies for engineering designer oilseeds of the future. Plant oils are a valuable renewable resource for food, fuels and chemicals. The genes that encode the enzymes responsible for lipid synthesis have been identified, but regulation of these genes is still poorly understood. This project will take a multi-disciplinary approach to study the role of newly discovered proteins in regulating a key early step in fatty acid synthesis, which in turn controls total plant oil accumulation. The project will prepare two undergraduate students, including underrepresented minorities, and two graduate students for STEM careers. They will be trained in modern research approaches of plant biotechnology, genetics, and protein science. The undergraduates from University of Southern Mississippi (USM; an especially diverse student population) will travel to University of Missouri (MU) to join the MU undergraduates for a 9-week intensive summer research experience for undergraduates in the Thelen and Van Doren laboratories. The graduate students at MU and USM will acquire transferable skills from formal training in mentoring and science communication and by mentoring the undergraduate students in research.This project leverages the expertise of a multi-disciplinary team to test the hypothesis that the newly discovered biotin attachment domain-containing (BADC) gene family and its counterpart biotin carboxyl carrier protein (BCCP) collectively act as a molecular rheostat to modulate acetyl CoA carboxylase (ACCase) activity and ultimately seed oil accumulation. Quantitative biophysical analyses will distinguish between two hypotheses for how BADC proteins intercalate into the holo-ACCase complex and reduce enzymatic activity. The analyses will test the alternatives of the BADC structure in solution versus its affinity for the BC subunit enabling BADC to compete with its functional, catalytic sibling protein, BCCP, for access to ACCase. The regulatory role of BADCs during seed development and induced regulation of fatty acid synthesis (FAS) will be characterized by quantifying gene expression and absolute protein levels of the BADC regulatory proteins relative to the ACCase enzyme, under various states of FAS. The rheostat hypothesis will be tested in planta by modulating BADC protein levels and quantifying carbon flux through ACCase and FAS and the effect on total oil accumulation. Additionally, the ability of BADC proteins to alleviate the FAS feedback inhibition that is induced in plants engineered to produce novel oils will be tested. This will clarify metabolic bottlenecks that limit oilseed engineering.