CAREER: Roles for Indole-3-butyric Acid in Plant Development

植物激素生长素调节植物生长发育，控制作物产量。吲哚-3-丁酸或IBA是一种非活性的生长素前体，其在植物体内的运输和转化为活性激素对生长素的功能至关重要。尽管IBA对植物生长非常重要，但控制IBA输入到有效生长素水平的机制还不是很清楚。这项建议旨在增加我们对IBA衍生的生长素如何影响植物生长的理解；这种理解将提供新的工具来改变植物的生长和发育，用于作物改良。这份职业建议书概述了在模式植物拟南芥和小球藻中阐明吲哚-3-丁酸(IBA)运输和IBA衍生生长素的发育作用的实验。生长素对植物是必不可少的，控制细胞分裂和细胞扩张，以协调许多发育事件和环境响应。IBA是一种生物活性不强的分子，被过氧化物体氧化转化为活性生长素IAA(吲哚-3-乙酸)。IBA衍生的生长素驱动一系列的幼苗发育过程，包括子叶和根毛细胞的扩张、顶端钩曲、高温诱导的下胚轴伸长、侧根产生和根分生组织的维持。与活性生长素IAA类似，生长素前体IBA是通过载体介导的机制运输的。本实验着重于了解IBA运输和IBA衍生的生长素在植物发育中的作用，有四个特定的目的：1)确定IBA向IAA转化的组织特异性。2)确定IBA传输的组成部分。3)研究IBA转运蛋白(TOB)家族对IBA转运和植物发育的调控。4)比较IBA衍生生长素和IBA转运在非维管束植物小球藻中的作用。这项研究将促进我们对生长素对植物发育调控的理解。这项研究还将支持创建一个基于探究的实验室，以增加华盛顿大学本科生研究的机会。这门课程解决了课程中对细胞生物学实验课程的迫切需求；本课程的主要目标是提高学生形成和检验假说的能力，并提高学生对可用于基础研究的各种生物系统的认识。这份提案的目标4将直接融入课程，学生将在学期末的吴研究研讨会上展示他们的工作。此外，这项研究将支持密苏里州地方生长素会议，该会议由国际生长素协会共同组织，以加强和扩大当地生长素社区，以及更多的K-12外联活动。

The plant hormone auxin regulates plant growth and development to control crop yield. Indole-3-butyric acid, or IBA, is an inactive auxin precursor whose transport throughout the plant and conversion to the active hormone is critical to auxin function. Despite the great importance of IBA to plant growth, the mechanisms controlling IBA input into the level of available auxin are not well understood. This proposal aims to increase our understanding of how IBA-derived auxin impacts plant growth; this understanding will provide new tools to alter plant growth and development for use in crop improvement. This CAREER proposal outlines experiments to elucidate developmental roles for indole-3-butyric acid (IBA) transport and IBA-derived auxin in the model plants Arabidopsis thaliana and Physcomitrella patens. Auxin is essential to plants, controlling cell division and cell expansion to orchestrate many developmental events and environmental responses. IBA is a biologically inactive molecule that is converted into the active auxin IAA (indole-3-acetic acid) by peroxisomal β-oxidation. IBA-derived auxin drives a wide range of seedling developmental processes, including cotyledon and root hair cell expansion, apical hook curvature, high-temperature-induced hypocotyl elongation, lateral root production, and root meristem maintenance. Similar to the active auxin IAA, the auxin precursor IBA is transported by carrier-mediated mechanisms.The proposed experiments focus on understanding roles for IBA transport and IBA-derived auxin in plant development with four specific aims: 1) To determine the tissue-specificity of IBA-to-IAA conversion. 2) To identify components of IBA transport. 3) To characterize TRANSPORTER OF IBA (TOB) family regulation of IBA transport and plant development. 4) To compare the roles of IBA-derived auxin and IBA transport in the nonvascular plant Physcomitrella patens. The proposed studies will advance our understanding of auxin regulation of plant development.This research will also support the creation of an inquiry-based laboratory to increase opportunities for undergraduate research at Washington U. This course addresses a critical need for a cell biology lab course in the curriculum; the primary objectives of this course are to increase student ability to form and test hypotheses and to raise student awareness of the diverse biological systems available for basic research. Aim 4 of this proposal will be directly integrated into the course and students will present their work at the WU Research Symposium at the end of the semester. In addition, this research will support the Missouri Local Auxin Meeting, co-organized by the PI to strengthen and expand the local auxin community, and additional K-12 outreach activities.