Zinc Finger Transcription Factors: Regulators of Growth, Development, and Alkaloid Biosynthesis

作为对环境信号的响应，植物战略性地将其能量和资源从生长、发育和繁殖转向使其能够适应、防御和生存的过程。植物需要规范这些过程，以最大限度地减少资源的浪费。这个项目将以长春花属植物(俗称马达加斯加长春花)产生的一类与防御相关的化合物(称为生物碱)为例，研究植物如何快速而准确地对攻击做出反应。在正常情况下，促进生长的同时生物碱的产量很低。但在病原体或攻击者的存在下，植物通过产生化学信号(如植物激素茉莉酸)来做出反应，从而迅速激活通讯系统，导致这些与防御相关的生物碱的产生。这个项目试图确定植物如何通过一类被称为锌指转录因子的调节开关来协调调节生长、发育和防御。这项研究将包括对研究生和本科生的跨学科指导和建议，以及通过教师和青年学者研究经验方案向K-12和代表性不足的群体推广。在长春花中，控制快速防御反应的机制部分是通过激活锌指长春花转录因子(ZCT)导致萜类吲哚生物碱的产生而调节的。除了萜类吲哚生物碱的生物合成，锌指转录因子似乎还参与了其他防御和应激相关的反应。在植物中，Cys2-His2型(C2H2)锌指是一类重要的转录因子，参与控制生长、发育和胁迫反应基因(冷、干旱、盐和氧化胁迫)，这些基因包含一个参与基因抑制的独特基序。然而，目前对植物C2H2锌指蛋白的详细研究还不多。其中，Zct的独特之处在于，它是唯一参与调节生长发育和国防相关生物碱生物合成的生物。这个项目的目标是更好地了解植物如何协调调节生长、发育和防御，以提高健康和适应能力。该项目旨在阐明激素输入通过zct协调生长、发育和生物碱生物合成的输出的调控网络。这些关于植物控制机制的基本知识和见解有望提高作物对逆境和病原体的抵抗力，改善具有药用价值的与防御相关的化合物的生产，并使人工遗传电路能够快速调节所需的产量。该项目的目的是1)阐明Zct通过激素茉莉酸激活其防御作用的调节回路；2)阐明Zct通过激素赤霉酸激活其在生长和发育中的作用的调节回路；以及3)表征Zct如何调节生长、发育和与国防相关的生物碱生物合成。该项目由系统和合成生物学(分子和细胞生物科学分部)和生物技术和生化工程(化学、生物工程、环境和运输系统分部)的项目共同支持。

In response to cues from their environment, plants strategically redirect their energy and resources from growth, development, and reproduction towards processes that enable adaptation, defense, and survival. Plants need to regulate these processes to minimize wasteful expenditures of resources. This project will investigate how plants respond quickly and precisely to attack by using the production of a class of defense-related compounds (called alkaloids) from the Catharanthus roseus plant (commonly known as the Madagascar periwinkle) as an example. Under normal conditions, growth is promoted while the production of alkaloids is low. But in the presence of pathogens or attackers the plant responds by producing chemical signals (such as the plant hormone jasmonic acid) which rapidly activates the communication system that leads to the production of these defense-related alkaloids. This project seeks to determine how the plant coordinately regulates growth, development, and defense through a class of regulatory switches, known as the zinc finger transcription factors. This research will involve the interdisciplinary mentoring and advising of graduate students and undergraduates, and the outreach to K-12 and under-represented groups through a Research Experience for Teachers and Young Scholars Program. In Catharanthus roseus, the mechanism for controlling the rapid defense response is partially mediated through activation of the zinc finger Catharanthus transcription (ZCT) factors leading to the production of terpenoid indole alkaloids. In addition to terpenoid indole alkaloid biosynthesis, zinc finger transcription factors appear to be involved in other defense and stress-related responses. In plants, Cys2-His2-type (C2H2) zinc fingers are an important class of transcription factors involved in controlling growth, development, and stress-responsive genes (cold, drought, salt, and oxidative stress) that contain a unique motif involved in gene repression. However, only a limited number of plant C2H2 zinc finger proteins have been studied in detail. Of these, ZCT is unique in that it is the only one involved in regulating growth and development and defense-related alkaloid biosynthesis. The goal of this project is to better understand how plants coordinately regulate growth, development, and defense to improve fitness and adaptation. This project seeks to elucidate the regulatory network by which hormone inputs coordinate the outputs of growth, development, and alkaloid biosynthesis through ZCT. This fundamental knowledge and insight regarding plant control mechanisms is anticipated to lead to improved resistance of crops towards stress and pathogens, to improved production of defense-related compounds that have medicinal value, and to artificial genetic circuits for enabling rapid regulation of a desired output. The aims for this project are to 1) elucidate the regulatory circuit by which ZCT's role in defense is activated through the hormone jasmonic acid; 2) elucidate the regulatory circuit by which ZCT's role in growth and development is activated through the hormone gibberellic acid; and 3) characterize how ZCT mediates growth, development, and defense-related alkaloid biosynthesis.This project is supported jointly by programs in Systems and Synthetic Biology (Division of Molecular and Cellular Biosciences) and Biotechnology and Biochemical Engineering (Division of Chemical, Bioengineering, Environmental, and Transport Systems).