Plant tolerance to abiotic stress: Physiological and metabolic mechanisms

植物对非生物胁迫的耐受性：生理和代谢机制

• 批准号: RGPIN-2015-06530
• 负责人: Weretilnyk, Elizabeth
• 金额: $ 2.4万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614198
• 关键词: Plant; tolerance; abiotic; stress; Physiological

We study a highly stress tolerant native plant, Eutrema salsugineum. In Canada, Eutrema is found on alkaline, saline soils in the Yukon and across the Prairies to western Ontario. As its distribution and soil preference implies, it has an extraordinary innate capacity to grow in cold areas where water is limiting and nutrients are low. Eutrema is an excellent model to study stress tolerance traits because of its close phylogenetic relationship to canola, Canada’s valuable oilseed crop. In the past four years many genetic and genomic resources have emerged to facilitate research on this plant and the Eutrema genomics group that I lead has made strong contributions to these advances. With fully sequenced genomes and transcriptomes available, we are in an excellent position to investigate the mechanisms underlying the exceptional capacity of this plant to withstand adverse conditions with a view to enhancing these traits in stress sensitive crops, including canola.     Drought and salt tolerant plants synthesize and accumulate non-perturbing organic solutes that enable them to establish a concentration gradient to drive water movement into the roots. Using physiology and metabolomics approaches, we reported that Eutrema shows plasticity with respect to the solutes they produce under stress. In the highly saline fields of the Yukon where nitrogen is low, Eutrema accumulates carbohydrates for osmotic adjustment and in our cabinets where salt-stressed plants are fertilized regularly, they accumulate the amino acid proline. Remarkably, salt-stressed cabinet plants provided low, but sufficient levels of nitrogen were visually indistinguishable from stressed plants given ample nitrogen. Normally a deficiency in nitrogen produces a severely stunted plant. Through our more recent transcriptome work we discovered that the Eutrema ecotype from the Yukon is actually sulfur deficient when grown in our cabinets although they are fertilized regularly and they do not look like they lack sulfur. Sulfur is a nutrient that also figures prominently in how plants respond to stress, particularly in suppressing the damage produced by reactive oxygen species. In the case of phosphorous, Eutrema can be extremely frugal and plants grow as well in a medium with a low content of phosphate as they do with a non-limiting supply of this nutrient, even in the presence of salt. It is clear that we have much to learn from how Eutrema manages low nutrient availability, particularly under stress. Our research objectives are focused on exploring mechanisms underlying the exceptional capacity for this plant to manage abiotic stresses, particularly under limiting nutrient conditions. High nutrient use efficiencies in crops that are more resilient against fluctuating weather patterns is an ideal combination of traits for sustainable crop production, particularly as the full impact of global climate change unfolds.

我们研究了一种高度抗逆的乡土植物盐地黄皮。在加拿大，Eutrema生长在育空地区的碱性和盐碱土上，并穿过大草原到达安大略西部。正如其分布和土壤偏好所暗示的那样，它具有非凡的内在能力，可以在水分有限和营养物质含量低的寒冷地区生长。Eutrema是一个很好的模式，研究抗逆性性状，因为它的密切的系统发育关系，加拿大的宝贵油料作物油菜。在过去的四年里，出现了许多遗传和基因组资源，以促进对这种植物的研究，我领导的Eutrema基因组学小组为这些进展做出了巨大贡献。有了完整的基因组测序和转录组，我们处于一个很好的位置来研究这种植物抵抗不利条件的特殊能力的机制，以期在包括油菜在内的应激敏感作物中增强这些性状。 耐旱和耐盐植物合成和积累非干扰有机溶质，使它们能够建立一个浓度梯度，以驱动水分运动到根部。利用生理学和代谢组学方法，我们报告说，Eutrema在压力下产生的溶质具有可塑性。在氮含量低的育空地区的高盐田地里，Eutrema积累碳水化合物进行渗透调节，在我们的盐胁迫植物定期施肥的橱柜里，它们积累氨基酸脯氨酸。值得注意的是，盐胁迫的盆栽植物提供低但足够水平的氮，与给予充足氮的胁迫植物在视觉上无法区分。正常情况下，氮的缺乏会使植物严重发育不良。通过我们最近的转录组工作，我们发现来自育空地区的Eutrema生态型在我们的橱柜中生长时实际上是缺硫的，尽管它们定期施肥，而且它们看起来不像缺硫。硫是一种营养素，在植物如何应对压力方面也很重要，特别是在抑制活性氧产生的损害方面。在磷的情况下，Eutrema可以非常节俭，植物在低含量磷酸盐的培养基中生长良好，因为即使在盐的存在下，这种营养素的非限制性供应也是如此。很明显，我们有很多东西要学习Eutrema如何管理低营养可用性，特别是在压力下。我们的研究目标集中在探索这种植物管理非生物胁迫的特殊能力的机制，特别是在有限的营养条件下。作物的高养分利用效率对波动的天气模式更具弹性，是可持续作物生产的理想特征组合，特别是在全球气候变化的全面影响显现的情况下。