Dimensions: Collaborative Research: Elucidating the drivers of mutualism variation in host-symbiont metapopulations

维度：合作研究：阐明宿主-共生复合种群中互利共生变异的驱动因素

基本信息

批准号：
1738009
负责人：
Joel Sachs
金额：
$ 89.28万
依托单位：
University of California-Riverside
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-10-01 至 2022-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1738009&HistoricalAwards=false
关键词：
Dimensions Collaborative Research Elucidating drivers

项目摘要

Symbiotic bacteria transform how plants and animals interact with their environment. These bacteria are well known for their ability to enhance host growth and tolerance to stress, but symbioses vary greatly in their effects on host health and fitness. Little is understood about the forces that shape this variation and drive the spread of symbionts that interact, but fail to benefit the host. Here, researchers use the relationship between native California legumes and nitrogen-fixing Bradyrhizobium bacteria to study the drivers of variation in symbioses. The project will employ environmental sampling of interacting plants, bacteria, and soil, genetic approaches, and greenhouse experiments. The research will determine the magnitude of benefits the bacteria provide to the host, what bacterial genes facilitate benefit or exploitation of the host, and how the host responds and defends itself against ineffective symbionts. The project will train undergraduate and graduate students as well as two postdoctoral fellows. The researchers will educate local farmers on plant-microbe interactions, and they will generate and curate a collection of plant and bacterial variants that will be made freely available to other researchers. The project is important because it will provide information on the parameters that influence symbiosis and help guide how microbes can be better deployed to increase productivity of agricultural systems and promote health of humans and the planet. The maintenance of diversity in microbial symbioses is paradoxical. Conventional theory predicts a lack of variation in symbiont function because host species reward beneficial symbionts and intensely select against ineffective partners. Here, a novel framework is tested to explain the maintenance of symbiont variation. The planned work transcends the dominant theoretical paradigm by investigating ecological, spatiotemporal, and genomic drivers in a metapopulation of rhizobial bacteria and their native legume hosts. Like other hosts, legumes exhibit host control traits: legumes can discriminate against ineffective rhizobia during nodule formation, and can reduce within-nodule growth rates of ineffective rhizobia. Despite the apparent efficiency of host control, ineffective rhizobia are commonly uncovered in natural and agricultural soils. Four aims are proposed to explain the maintenance of symbiont variation in this key model system. Experimental inoculations coupled with genetic and selection analysis are used to investigate i) variation among legume host populations in their capacity to sanction ineffective rhizobia, ii) the spatial and phylogenetic origins of invasions by ineffective rhizobia, and iii) the genomic basis for the evolution of ineffective rhizobia. iv) Inferred invasions of ineffective rhizobia will be recapitulated using experiments that test fitness predictions under realistic conditions. This work challenges conventional mutualism theory and highlights the importance of genetic variation, spatio-temporal dynamics, and fitness tradeoffs.

共生细菌改变了植物和动物如何与环境相互作用。这些细菌以增强宿主生长和对压力的耐受性的能力而闻名，但共生对宿主健康和适应性的影响差异很大。关于塑造这种变化并推动相互作用但无法使宿主受益的共生体传播的力的力量知之甚少。在这里，研究人员使用了加利福尼亚本地豆类与氮的胸膜细菌之间的关系来研究共生体变异的驱动因素。该项目将采用相互作用的植物，细菌和土壤，遗传方法和温室实验的环境采样。这项研究将确定细菌为宿主提供的益处的大小，哪些细菌基因促进宿主的益处或剥削，以及宿主如何反应和捍卫自己免受无效的共生体的反应。该项目将培训本科生和研究生以及两个博士后研究员。研究人员将教育当地农民有关植物菌相互作用的教育，他们将生成和策划一系列植物和细菌变体，这些变体将免费提供给其他研究人员。该项目很重要，因为它将提供有关影响共生的参数的信息，并帮助指导如何更好地部署微生物以提高农业系统的生产率并促进人类和地球的健康。微生物共生的多样性维持是自相矛盾的。传统理论预测共生函数的缺乏变化，因为宿主物种奖励有益的共生体并强烈选择反对无效的伴侣。在这里，测试了一个新型框架，以解释共生体变化的维持。计划的工作超越了主要的理论范例，通过研究根瘤菌细菌及其本地豆科植物宿主的生态，时空和基因组驱动因素。像其他宿主一样，豆类也表现出宿主控制特征：豆类可以在结节形成过程中歧视无效的根瘤菌，并可以降低无效性根瘤内结节内生长速率。尽管宿主控制的效率明显，但在自然和农业土壤中通常会发现无效的根瘤菌。提出了四个目标来解释该关键模型系统中共生体变化的维护。实验接种与遗传分析和选择分析相结合用于研究i）豆类宿主种群之间的变化，以批准无效性根瘤菌的能力，ii）无效性根瘤菌的侵袭的空间和系统发育起源，以及iiii）iii）的基因组基因组基因组效果的基因组基础。 iv）推断出无效性根瘤菌的入侵将使用在现实条件下测试适应性预测的实验来概括。这项工作挑战了传统的互助理论，并强调了遗传变异，时空动态和健身折衷的重要性。

项目成果

期刊论文数量（15）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

No disruption of rhizobial symbiosis during early stages of cowpea domestication

豇豆驯化早期阶段根瘤菌共生没有受到破坏

DOI：
10.1111/evo.14424
发表时间：
2022
期刊：
Evolution
影响因子：
3.3
作者：
Ortiz‐Barbosa, Gabriel S.;Torres‐Martínez, Lorena;Manci, Angela;Neal, Sierra;Soubra, Tarek;Khairi, Fizzah;Trinh, Jerry;Cardenas, Paola;Sachs, Joel L.
通讯作者：
Sachs, Joel L.

Host investment into symbiosis varies among genotypes of the legume Acmispon strigosus , but host sanctions are uniform

豆科植物Acmispon strigosus的不同基因型对共生的宿主投入有所不同，但宿主的制裁是一致的。

DOI：
10.1111/nph.15378
发表时间：
2018
期刊：
New Phytologist
影响因子：
9.4
作者：
Wendlandt, Camille E.;Regus, John U.;Gano-Cohen, Kelsey A.;Hollowell, Amanda C.;Quides, Kenjiro W.;Lyu, Jonathan Y.;Adinata, Eunice S.;Sachs, Joel L.
通讯作者：
Sachs, Joel L.

Recurrent mutualism breakdown events in a legume rhizobia metapopulation

DOI：
10.1098/rspb.2019.2549
发表时间：
2020-01-29
期刊：
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
影响因子：
4.7
作者：
Gano-Cohen, Kelsey A.;Wendlandt, Camille E.;Sachs, Joel L.
通讯作者：
Sachs, Joel L.

Evolution of specialization in a plant‐microbial mutualism is explained by the oscillation theory of speciation

物种形成振荡理论解释了植物的专业化进化——微生物互利共生

DOI：
10.1111/evo.14222
发表时间：
2021
期刊：
Evolution
影响因子：
3.3
作者：
Torres‐Martínez, Lorena;Porter, Stephanie S.;Wendlandt, Camille;Purcell, Jessica;Ortiz‐Barbosa, Gabriel;Rothschild, Jacob;Lampe, Mathew;Warisha, Farsamin;Le, Tram;Weisberg, Alexandra J.
通讯作者：
Weisberg, Alexandra J.

Legumes versus rhizobia: a model for ongoing conflict in symbiosis

豆类与根瘤菌：共生中持续冲突的模型