Investigating salinity tolerance in alfalfa (Medicago sativa L.): modern synchrotron and molecular approaches

研究苜蓿 (Medicago sativa L.) 的耐盐性：现代同步加速器和分子方法

基本信息

批准号：
RGPIN-2016-06082
负责人：
Biligetu, Bill
金额：
$ 2.04万
依托单位：
University of Saskatchewan
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2020
资助国家：
加拿大
起止时间：
2020-01-01 至 2021-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709900
关键词：
Investigating salinity tolerance alfalfa Medicago

项目摘要

My long term research goal is to develop alfalfa (Medicago sativa L.) cultivars with tolerance to abiotic and biotic stresses. My short-term (5-year) objectives for this proposal are to investigate how alfalfa tolerates soil salinity at a whole plant level. I assume spatial and temporal distributions of elemental ions and organic solutes in the leaves, stems, and roots of alfalfa will vary between salt tolerant and susceptible cultivars under a salt stress. A salinity tolerant alfalfa must have a unique osmotic regulation through organic molecules or K+ and Ca2+ ions to reduce ion toxicity in the leaves. I also investigate if links exist among gene expression and biochemical changes and stress hormone's concentration in the leaves. To test my hypothesis, two alfalfa cultivars with contrasting tolerance to salinity will be exposed to different salt solutions and plants will be sampled periodically following salt treatments. Synchrotron radiation (SR) based phase contrast X-ray imaging, mid-infrared, soft X-ray, and X-ray Fluorescence mapping at the Canadian Light Source (Saskatoon, Canada) will be applied to quantify and localize elemental ions, organic solutes and detect their spatial and temporal distributions in alfalfa tissues. Synchrotron radiation-Fourier transform infrared (SR-FTIR) spectroscopy will be used to map changes in the ratios of carbohydrates, and -helix to -sheet protein secondary structures. A transcriptomic analysis of gene expression in alfalfa leaves in response to salt stress will be performed, and based on the RNA-seq analysis, and available genomic information of the model legume, Medicago truncatula, identify candidate genes to salinity tolerance in alfalfa and validate the expression of selected genes. Alfalfa is the most widely planted forage legume in the world. Soil salinity is a major abiotic factor that limits alfalfa production in many regions of the world. Knowledge of the biochemical composition of alfalfa tissues under salt stress is critical for the study of stress tolerance physiology, but there is a limited information available on quantification in whole plant level and spatial localization of those compounds at the tissue, cellular and subcellular levels. A comprehensive understanding of salinity tolerance in alfalfa is needed for development of novel cultivars. The proposed project has a goal to train Highly Qualified Personnel (HQP) including one M.Sc. student in forage stress physiology and synchrotron application, and one Ph.D. student in alfalfa genomics, two undergraduate thesis students in experimental design, statistics, plant physiology, and basic bio-technology skills. The findings will advance our understanding of the physiology and genetics of salt tolerance in alfalfa. The identification of genes will be useful for breeding new alfalfa varieties with high salinity tolerance.

我的长期研究目标是开发苜蓿（Medicago sativa L.）品种，耐受性和生物胁迫。我对该提案的短期（5年）目标是调查苜蓿如何在整个植物水平上耐受土壤盐度。我假设在盐胁迫下，苜蓿的叶子，茎和根中的元素离子和有机溶质的空间和时间分布在耐盐和易感品种之间会有所不同。盐度耐苜蓿必须通过有机分子或K+和Ca2+离子具有独特的渗透调节，以降低叶片中的离子毒性。我还研究了基因表达和生化变化和叶子中压力激素的浓度之间是否存在联系。为了检验我的假设，将在盐处理后定期对两个具有对比盐度的苜蓿品种对不同的盐溶液进行对比。基于同步加速器辐射（SR）对比度X射线成像，加拿大光源（加拿大萨斯卡通）的中红外，软X射线和X射线荧光映射将用于量化和定位元素离子，有机离子，有机溶质，并检测其在Alfalfa组织中的空间和临时分布。同步加速器辐射式转换红外（SR -FTIR）光谱将用于绘制碳水化合物比的变化，以及-Helix与-sheet蛋白二级结构。将对苜蓿叶片中基因表达的转录组分析对盐胁迫进行，并基于RNA-Seq分析，并基于RNA-Seq分析，并基于模型豆科植物的可用基因组信息，Medicago truncatula，鉴定αFALFA中的候选基因对盐度耐受性，并验证所选基因的表达。苜蓿是世界上种植最广泛的饲料豆类。土壤盐度是限制世界许多地区苜蓿产量的主要非生物因素。对盐胁迫下苜蓿组织的生化组成的了解对于胁迫耐受性生理的研究至关重要，但是在整个植物水平上的定量和空间定位的信息有限，在组织，细胞和亚细胞水平上的空间定位。为了开发新品种，需要对苜蓿中的盐度耐受性进行全面的了解。拟议的项目的目标是培训高素质的人员（HQP），包括一名硕士学位。觅食应力生理和同步加速器的学生的学生，以及一位博士学位。苜蓿基因组学的学生，两位实验设计，统计学，植物生理学和基本生物技术技能的大学生。这些发现将提高我们对苜蓿耐盐性耐受性的生理和遗传学的理解。鉴定基因将有助于繁殖具有高盐度耐受性的新苜蓿品种。