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MicroRNA-mediated plant development and response to environmental stress in perennial grasses.

机译：多年生草中MicroRNA介导的植物发育和对环境胁迫的响应。

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摘要

World population will pass nine billion by 2050, while the agricultural land area will not increase dramatically in the coming decades. To meet the ever-increasing food demand, genetically engineered crops have been rapidly adopted for crop productivity. MicroRNAs have become increasingly attractive as targets in crop genetic modification due to their regulatory role in fine-tuning many essential biological processes. My research explores the potentials of microRNA528 (miR528) and miR396 for use in genetic modifications of the important agronomic traits of plant development, abiotic stress response, and/or flowering time control in an economically and environmentally important perennial monocot species, creeping bentgrass (Agrostis stolonifera ).;MiR528 is a conserved monocot-specific small RNA which is involved in multiple stress responses, however, experimental functional studies are lacking. In this study, we generated transgenic creeping bentgrass overexpressing a rice miRNA, Osa-miR528. Transgenic plants show altered plant development and enhanced salt and nitrogen (N) deficiency tolerance. The developmental changes include shortened internodes, increased tillers, and relatively upright growth. Enhanced salt stress tolerance is associated with improved water, chlorophyll, and potassium retention, cell membrane integrity, increased proline content, CATALASE activity, and reduced ASCORBIC ACID OXIDASE (AAO) activity; while improved N deficiency is associated with increased biomass, total N accumulation, chlorophyll synthesis, nitrite reductase activity, and reduced AAO activity. Molecular analysis identified AAO and COPPER ION BINDING1 as putative targets of miR528 in creeping bentgrass. Both putative targets respond to salt stress and N deficiency.;The conserved miR396 is involved in plant vegetative and reproductive development and various environmental stress responses through targeting Growth Regulating Factor (GRF) transcription factor genes. In this study, we generated transgenic creeping bentgrass overexpressing a rice miRNA, Osa-miR396c. The transgenic plants exhibit altered development in both vegetative and reproductive growth, elimination of vernalization requirement, and enhanced salt stress tolerance. The altered plant development includes less shoot and root biomass, shorter internodes, smaller leaf area, fewer leaf veins and epidermal cells, and defects in filament elongation, anther dehiscence, and pollen viability. The enhanced salt tolerance is associated with improved water and chlorophyll retention, cell membrane integrity, and sodium ion exclusion during salt stress. The elimination of vernalization requirement is associated with the regulation of key genes VRN1, VRN2 , and VRN3 in the vernalization pathway. Four putative targets AsGRF3-6 were identified in creeping bentgrass. These targets respond to high salinity, long-day photoperiod, and prolonged cold exposure. RNA-seq analysis shows that differentially expressed genes are involved in cell division, floral organ development, vegetative to reproductive transition, histone modification, oxidation reduction, environmental stress response, etc.;The study established the molecular pathways of miR528- and miR396-mediated plant salt stress and/or N deficiency tolerance in creeping bentgrass. It provides insight into miRNA-mediated regulatory network in plant vegetative and reproductive development, abiotic stress response and flowering time control.
机译：到2050年，世界人口将超过90亿，而在未来几十年中，农业用地面积将不会急剧增加。为了满足不断增长的粮食需求，转基因作物已被迅速用于提高作物生产力。由于MicroRNA在微调许多基本生物学过程中的调控作用，其作为作物基因修饰的靶标已变得越来越有吸引力。我的研究探索了microRNA528（miR528）和miR396在重要的农艺性状的遗传修饰中的潜力，这些农艺性状在经济上和环境上重要的多年生单子叶植物，蔓生的草木（Agrostis） MiR528是保守的单子叶植物特异性小RNA，参与多种应激反应，但缺乏实验功能研究。在这项研究中，我们生成了过表达水稻miRNA Osa-miR528的转基因爬行草根草。转基因植物显示出改变的植物发育和增强的盐和氮（N）缺乏耐受性。发育变化包括节间缩短，分till增加和相对直立的生长。增强的盐胁迫耐受性与改善的水，叶绿素和钾保留，细胞膜完整性，脯氨酸含量，CATALASE活性增加以及抗坏血酸氧化酶（AAO）活性有关；而改善的氮缺乏与生物量增加，总氮积累，叶绿素合成，亚硝酸还原酶活性和AAO活性降低有关。分子分析确定了AAO和COPPER ION BINDING1是creep草中miR528的假定靶标。两种推测的靶标均对盐胁迫和氮缺乏做出响应。保守的miR396通过靶向生长调节因子（GRF）转录因子基因参与植物的营养和生殖发育以及各种环境胁迫响应。在这项研究中，我们生成了过表达水稻miRNA Osa-miR396c的转基因爬行性草根草。转基因植物的营养生长和生殖生长均发生了变化，消除了春化要求，并增强了耐盐胁迫性。改变后的植物发育包括更少的枝条和根生物量，更短的节间，更小的叶面积，更少的叶脉和表皮细胞，以及花丝伸长，花药开裂和花粉活力的缺陷。在盐胁迫期间，提高的耐盐性与改善的水和叶绿素保留能力，细胞膜完整性和钠离子排斥有关。消除春化要求与春化途径中关键基因VRN1，VRN2和VRN3的调节有关。在creep草中鉴定出四个推定的靶标AsGRF3-6。这些目标对高盐度，长时间的光周期和长时间的冷暴露有反应。 RNA-seq分析表明差异表达的基因参与细胞分裂，花器官发育，营养向生殖过渡，组蛋白修饰，氧化还原，环境胁迫反应等；该研究建立了miR528和miR396介导的分子途径。 bent草中的植物盐分胁迫和/或氮缺乏耐受性。它提供了有关miRNA介导的植物营养和生殖发育，非生物胁迫响应和开花时间控制的调控网络的见解。

著录项

  • 作者

    Yuan, Shuangrong.;

  • 作者单位

    Clemson University.;

  • 授予单位 Clemson University.;
  • 学科 Genetics.;Agronomy.;Plant sciences.;Physiology.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 211 p.
  • 总页数 211
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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