RESEARCH-PGR: Genetics and Mechanisms of Microbe-dependent Heterosis

研究-PGR：微生物依赖性杂种优势的遗传学和机制

• 批准号: 2033621
• 负责人: Maggie Wagner
• 金额: $ 90万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2033621&HistoricalAwards=false
• 关键词: RESEARCH; PGR; Genetics; Mechanisms; Microbe

In corn and many other crop and wild plants, hybrid cultivars are larger, more resilient, and more productive than their inbred parent cultivars. This phenomenon, called hybrid vigor, is a cornerstone of modern crop breeding efforts and has immense value for global food security. Despite over a century of intensive research, the causes of hybrid vigor are still poorly understood. Recently, the first evidence has arisen that microbes in the soil play an important role in hybrid vigor. This project will investigate the microbial contribution to hybrid vigor in more detail, combining classic and cutting-edge scientific approaches, including field experiments, microbial culture, DNA sequencing, and advanced molecular techniques such as metaproteomics. Specifically, this study will (1) test a wide range of microbial strains and soil microbiomes for the ability to induce hybrid vigor in corn; (2) identify genetic variants and regions of the corn genome that are associated with responsiveness to soil microbes; and (3) characterize the behavior of microbes within the roots of inbred and hybrid corn at the molecular level. Together, the results will advance knowledge of how, when, and why soil microbes affect hybrid vigor which could potentially lead to applications in agriculture and ecological conservation. This project will also grow the American scientific workforce by supporting the training of two post-doctoral researchers, one Ph.D. student, and two undergraduate student researchers. It will also support four high-school teachers to attend researcher-led workshops to learn about soil microbes and agricultural ecosystems.This project was motivated by preliminary data showing that hybrid vigor (i.e., heterosis) of maize root mass was eliminated or greatly reduced in sterile conditions or diminished soil microbial communities in the field. The overarching goals are to determine the generality of this phenomenon with respect to the microbes and host genotypes; to investigate the genetic architecture of microbe-dependent heterosis; and to characterize molecular mechanisms of microbial interactions with inbred and hybrid hosts. An existing collection of maize root endophytes will be screened for the ability to induce maize heterosis, in monoculture and in simplified communities. Metaproteomics will be used to quantify in planta protein expression by heterosis-inducing and non-inducing bacterial strains while colonizing roots of inbred vs. hybrid hosts, while RNA-seq will be used to quantify host gene expression aboveground. The generality of microbe-induced heterosis will be assessed by measuring better-parent heterosis in a genetically diverse panel of maize hybrids and their parent lines, under sterile and inoculated conditions. Finally, a high-resolution mapping population (“IBM”) will be backcrossed to each parent line, generating a test population that will be used to map genomic loci that interact with microbes to affect phenotype when in the heterozygotic state. The same test population will be scored for disease resistance in the field to investigate the interplay with plant immunity. Together, these experiments will help clarify how inbred and hybrid maize plants interact with their microbial neighbors, and how these interactions relate to the expression of phenotypic heterosis. All data and genetic resources will be made available to the general public through long-term repositories.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在玉米和许多其他作物和野生植物中，杂交品种比其近交亲本品种更大，更有弹性，更有生产力。这种现象被称为杂种优势，是现代作物育种工作的基石，对全球粮食安全具有巨大价值。尽管经过了世纪的深入研究，杂种优势的原因仍然知之甚少。最近，第一个证据表明，土壤中的微生物在杂种优势中起着重要作用。该项目将更详细地研究微生物对杂种优势的贡献，结合经典和尖端的科学方法，包括田间实验，微生物培养，DNA测序和先进的分子技术，如元蛋白质组学。具体而言，本研究将（1）测试各种微生物菌株和土壤微生物组诱导玉米杂交活力的能力;（2）确定与土壤微生物反应相关的玉米基因组遗传变异和区域;（3）在分子水平上表征近交和杂交玉米根内微生物的行为。总之，这些结果将促进土壤微生物如何，何时以及为什么影响杂种优势的知识，这可能会导致农业和生态保护的应用。该项目还将通过支持培训两名博士后研究人员，一名博士，学生和两名本科生研究人员。它还将支持四名高中教师参加研究人员领导的研讨会，以了解土壤微生物和农业生态系统。在无菌条件下或田间土壤微生物群落减少的情况下，玉米根质量的杂种优势（优势）被消除或大大降低。总体目标是确定这种现象的微生物和宿主基因型的一般性;调查微生物依赖的杂种优势的遗传结构;以及表征微生物与近交和杂交宿主相互作用的分子机制。将在单一栽培和简化的群落中筛选现有的玉米根内生菌集合诱导玉米杂种优势的能力。元蛋白质组学将用于定量杂种优势诱导和非诱导细菌菌株在植物中的蛋白质表达，同时定殖近交与杂交宿主的根，而RNA-seq将用于定量地上宿主基因表达。微生物诱导的杂种优势的一般性将通过在无菌和接种条件下测量遗传多样性的玉米杂交种及其亲本系中的更好的亲本杂种优势来评估。最后，将高分辨率作图群体（“IBM”）与每个亲本系回交，产生测试群体，所述测试群体将用于作图基因组基因座，所述基因组基因座在杂合状态下与微生物相互作用以影响表型。将在田间对相同的测试群体的抗病性进行评分，以研究与植物免疫的相互作用。总之，这些实验将有助于阐明自交系和杂交玉米植物如何与它们的微生物邻居相互作用，以及这些相互作用如何与表型杂种优势的表达相关。 所有数据和遗传资源将通过长期储存库向公众提供。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Screening the maize rhizobiome for consortia that improve Azospirillum brasilense root colonization and plant growth outcomes

• DOI: 10.3389/fsufs.2023.1106528
• 发表时间: 2023-04
• 作者: Niloy Barua;Kayla M. Clouse;D. R. Ruiz Diaz;Maggie R. Wagner;Thomas G. Platt;Ryan R. Hansen

Microbe-dependent heterosis in maize

• DOI: 10.1073/pnas.2021965118
• 发表时间: 2021-07-27
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Wagner, Maggie R.;Tang, Clara;Kleiner, Manuel
• 通讯作者: Kleiner, Manuel