Transcription Regulatory Circuits of Grass Cell Wall Biosynthesis

草细胞壁生物合成的转录调控回路

• 批准号: 1558072
• 负责人: Samuel Hazen
• 金额: $ 71.34万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558072&HistoricalAwards=false
• 关键词: Transcription; Regulatory; Circuits; Grass; Cell

The costs of degrading cellulosic biomass currently impede its widespread use as a competitive domestic renewable alternative to fossil fuels. A promising route to renewable liquid fuels is the conversion of various biomass sources by microbial organisms. The goal for this project is to develop a basic understanding of the genes that control biomass accumulation. This will enable our long-term goal of producing ecologically and economically sustainable sources of feedstocks for biofuels. The research specifically addresses the genes that regulate a key aspect of plant growth, which is the creation of cell walls. In specific cells the walls are very thick and it is these that account for the bulk of all plant biomass. Grasses include many of our most important food and forage crops including maize, wheat, rice, ryegrass, and tall fescue. Despite the importance of the plant cell wall for plant growth, our knowledge of the precise regulatory mechanisms that give rise to the coordinated synthesis of the wall polymers is limited. This is especially true of grasses. This project will provide interdisciplinary training in development, genetics, genomics, and biochemistry for at least two University of Massachusetts graduate students and facilitate an internship program with the National Technical Institute for the Deaf.This proposal aims at understanding the transcription networks that regulate secondary cell wall biosynthesis in grasses. The cell wall is a complex composite of polysaccharides, proteins, and lignin. Much of what is currently understood about the transcriptional regulation of cell wall biosynthesis is from the study of Arabidopsis thaliana xylem vessels and fibers, yet this understanding may not be generalizable across land plants. The cell walls of grasses, including domesticated cereals that provide the majority of human calories and the perennials under development as biofuel energy crops, differ significantly in morphology and composition from the eudicot A. thaliana. The research will explore the function of three Brachypodium distachyon transcription factors: GRASS NAC REPRESSOR OF FLOWERING (GNRF), WALL REGULATOR INTERACTING bHLH (WRIB), KNOTTED-LIKE HOMEOBOX OF BRACHYPODIUM DISTACHYON7 (KNOB7). The researchers hypothesize that these proteins regulate wall biosynthesis through protein-protein and protein-DNA interactions that make-up a system of feed forward and negative feedback loops that are influenced by external cues. Transcription factors will be characterized by using methods such as chromatin immunoprecipitation to determine the gene promoter targets of the proteins and the effect of binding on cell wall biosynthesis. Protein-protein interactions will be evaluated using co-immunoprecipitation. A possible role for photo and thermocycles in the function of cell wall regulation will be tested by measuring function under varying time course conditions in plants of different mutant backgrounds.

目前，纤维素生物质的降解成本阻碍了其作为化石燃料的有竞争力的国内可再生替代品的广泛应用。获得可再生液体燃料的一条有前途的途径是通过微生物有机体转化各种生物质来源。该项目的目标是对控制生物量积累的基因有一个基本的了解。这将使我们的长期目标成为可能，即生产生态和经济上可持续的生物燃料原料来源。该研究专门针对调节植物生长的一个关键方面的基因，即细胞壁的形成。在特定的细胞中，细胞壁非常厚，正是这些细胞构成了所有植物生物量的大部分。草类包括许多最重要的粮食和饲料作物，包括玉米、小麦、水稻、黑麦草和高羊茅。尽管植物细胞壁对植物生长很重要，但我们对细胞壁聚合物协调合成的精确调节机制的了解仍然有限。对于草来说尤其如此。该项目将为至少两名马萨诸塞大学研究生提供发育、遗传学、基因组学和生物化学方面的跨学科培训，并促进国家聋人技术研究所的实习计划。该提案旨在了解调节草类次生细胞壁生物合成的转录网络。细胞壁是多糖、蛋白质和木质素的复杂复合物。目前对细胞壁生物合成转录调控的了解大部分来自对拟南芥木质部导管和纤维的研究，但这种理解可能无法推广到陆地植物。草类的细胞壁，包括为人类提供大部分热量的驯化谷物和作为生物燃料能源作物开发的多年生植物，在形态和组成上与真双子叶植物拟南芥有显着差异。该研究将探索短柄草三个转录因子的功能：GRASS NAC REPRESSOR OF FLOWERING (GNRF)、WALL REGULATOR INTERACTING bHLH (WRIB)、短柄草打结状同源盒7 (KNOB7)。研究人员推测，这些蛋白质通过蛋白质-蛋白质和蛋白质-DNA 相互作用来调节壁生物合成，这些相互作用构成了受外部线索影响的前馈和负反馈循环系统。 将通过使用染色质免疫沉淀等方法来表征转录因子，以确定蛋白质的基因启动子靶标以及结合对细胞壁生物合成的影响。将使用免疫共沉淀来评估蛋白质-蛋白质相互作用。通过测量不同突变背景植物在不同时间过程条件下的功能，可以测试光循环和热循环在细胞壁调节功能中的可能作用。