The betalain secondary metabolic network.

甜菜碱次级代谢网络。

• 批准号: 1122179
• 负责人: Alan Lloyd
• 金额: $ 68.29万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1122179&HistoricalAwards=false
• 关键词: betalain; secondary; metabolic; network.

Intellectual merit: Beets and roses are red for completely different reasons. Virtually all flowering plants contain one of two mutually exclusive red/purple pigment pathways, anthocyanins or betalains. The anthocyanin biosynthetic / regulatory network has been heavily studied and occurs in the vast majority of taxa including the major crop families: Poaceae (grasses), Brassicaceae (canola, mustards, cole crops), and Rosaceae (apples, pears, cherries). Betalains on the other hand are restricted to certain families of a single order, the Caryophyllales, where they assume the role of anthocyanin pigments in all biological contexts. These roles include attracting pollinators and seed dispersal agents, and as protective pigments during stress and aging. The betalain families contain crop species and ornamentals that are grown worldwide and form important staples in many agricultural economic systems, including Beets, Spinach, Amaranthus, Quinoa, and Prickly Pear cactus. This project is aimed at understanding the betalain biosynthetic and regulatory network at the molecular level and how pigment emergent properties are generated. While anthocyanins are based on the amino acid phenylalanine, while betalains derive from the animo acid tyrosine. Prior to the start of this project, the investigators identified a novel cytochrome P450 enzyme and a MYB-type transcription factor regulator that function in the betalain network. In particular, hypotheses will be tested regarding the identity of the last unknown betalain ring structure biosynthetic enzyme by silencing genes in beet to test their functions and beet gene expression in yeast to test function. One hypothesis is that betalains are regulated by the same set of interacting proteins that regulate the anthocyanin pigment pathway in other plants. The investigators will test this hypothesis using gene silencing and overexpression in beet. Anthocyanin pigments are regulated by well-characterized environmental signals. The hypothesis that betalains are regulated by these same signaling pathways will be tested. In order to ask the question about whether environmental signals work through increasing gene expression of the MYB regulator, plants will be treated with known elicitors and plant hormones, or nutrient deprivation (e.g. phosphate), and expression of all know betalain network genes will be measured. The hypothesis that the MYB regulator directly binds to cis regions of the betalain biosynthetic genes will be tested through protein-DNA binding assays.Broader impacts: This research will enhance our basic understanding of the control of plant secondary metabolic networks. Betalains are important dietary antioxidants with high human availability and this project will lead to an ability to manipulate this network and to move the pathway into heterologous systems. Eventual impacts include the ability to create crops that are more nutritious for humans and livestock. The project will provide excellent training for all levels of students. Integral to this project is a new inquiry-based Freshman Research Initiative stream for 30+ students that emphasizes creative and critical thinking within science. Students receive lecture-based training in hypothesis building and testing, data collection, record-keeping, statistical analysis, and ethical research standards. In the spring, students enter the stream for two semesters of hands-on self-directed research. For the past ten years, all lab members, including undergrad and grad students, have participated in judging yearly science fairs at local elementary schools, including interactive interviews of the elementary students. For the past six years, the PI and his graduate students have conducted prefair outreach workshops at the schools. This past year, 3 graduate students, about 180 4th and 5th graders, and 6 teachers participated in the workshop on hypothesis driven scientific method, project conception, and project execution. This outreach activity will continue throughout the period of this project.

智力优点： 甜菜和玫瑰是红色的原因完全不同。几乎所有的开花植物都含有两种相互排斥的红色/紫色色素途径之一，花青素或甜菜色素。花色素苷生物合成/调节网络已经被大量研究，并且存在于绝大多数分类群中，包括主要作物家族：禾本科（禾本科）、油菜科（油菜、芥菜、科尔作物）和蔷薇科（苹果、梨、樱桃）。另一方面，Betalains仅限于单一目的的某些家族，即Carlisllales，在所有生物学背景中，它们承担花青素色素的作用。这些作用包括吸引传粉者和种子传播媒介，以及在压力和老化期间作为保护色素。甜菜素家族包含在世界范围内种植的作物物种和观赏植物，是许多农业经济系统的重要斯台普斯，包括甜菜、菠菜、苋菜、藜麦和仙人掌。该项目旨在了解甜菜色素在分子水平上的生物合成和调控网络，以及如何产生色素紧急属性。 花色素苷是基于氨基酸苯丙氨酸，而甜菜色素衍生自氨基酸酪氨酸。在该项目开始之前，研究人员确定了一种新的细胞色素P450酶和一种在甜菜色素网络中起作用的MYB型转录因子调节剂。特别地，将通过沉默甜菜中的基因以测试它们的功能和在酵母中的甜菜基因表达以测试功能来测试关于最后未知的甜菜色素环结构生物合成酶的身份的假设。一种假设是甜菜色素是由调节其他植物中花青素色素途径的同一组相互作用蛋白质调节的。研究人员将使用甜菜中的基因沉默和过度表达来验证这一假设。花色素苷色素是由特征明确的环境信号调节的。将测试甜菜色素受这些相同的信号传导途径调节的假设。为了询问关于环境信号是否通过增加MYB调节剂的基因表达起作用的问题，将用已知的激发子和植物激素或营养剥夺（例如磷酸盐）处理植物，并测量所有已知甜菜色素网络基因的表达。MYB调节剂直接结合甜菜色素生物合成基因的顺式区域的假设将通过蛋白质-DNA结合测定进行测试。 本研究将加深我们对植物次生代谢网络控制的基本认识。Betalains是重要的膳食抗氧化剂，具有高的人类可用性，该项目将导致能够操纵这个网络，并将该途径转移到异源系统中。最终的影响包括创造对人类和牲畜更有营养的作物的能力。该项目将为各级学生提供出色的培训。这个项目的组成部分是一个新的基于调查的新生研究计划流30+学生，强调科学内的创造性和批判性思维。学生接受基于讲座的假设建立和测试，数据收集，记录保存，统计分析和道德研究标准的培训。在春季，学生进入两个学期的实践自我指导的研究流。 在过去的十年里，所有实验室成员，包括本科生和格拉德生，都参加了当地小学的年度科学博览会，包括对小学生的互动采访。在过去的六年里，PI和他的研究生在学校举办了博览会前的外联讲习班。在过去的一年里，3名研究生，约180名四年级和五年级学生，以及6名教师参加了关于假设驱动的科学方法，项目概念和项目执行的研讨会。这一外联活动将在整个项目期间继续进行。