RESEARCH-PGR: Characterizing the Genomic Basis of Weedy Rice Competitiveness

在美国和全球范围内，困扰农田的杂草是限制全球农业生产力的主要因素。水稻生产中最棘手的杂草之一是杂草水稻（Oryza sativa），它是栽培水稻的近亲，在稻田中肆虐，并积极地与其他作物品种竞争。这项研究旨在了解和描述杂草水稻入侵稻田、降低产量和污染收成的性状的遗传基础和起源。杂草水稻生长和繁殖的三个关键特征将被描述为：根系生长模式，使杂草能够与水稻竞争土壤养分；稻田杂草种子传播机制的遗传和发育基础；稻瘟病是一种常见的稻田真菌病，而这种杂草对稻瘟病的抵抗力也不同。除了提供有关杂草水稻竞争力基础的关键见解外，该项目还将为水稻研究界提供遗传资源，为K-12科学教师提供培训机会，并为包括听力残疾学生在内的学生提供教育培训经验，听力残疾学生是STEM职业中代表性不足的少数群体。杂草稻（Oryza sativa）是世界范围内水稻产区的一种侵略性杂草。它通过从栽培水稻的“去驯化”（feralization）过程独立进化了多次。因此，该系统为研究杂草性状的遗传机制以及这些性状受遗传背景限制的程度提供了一个自然的复制实验。合作研究小组先前的工作已经确定，杂草水稻在竞争中积极胜过其栽培亲属，部分原因在于三个关键特征：根系结构改变（对地下资源获取至关重要），种子高度碎裂（赋予不同的繁殖成功率和传播能力），以及不同的病原体抗性（允许在美国作物领域具有竞争优势）。本项目将对杂草稻竞争力的这些特征进行描述，具体目标如下：1)确定随着杂草稻的重复起源而趋同进化的根系结构（RSA）的遗传基础，并通过差异养分吸收建立杂草稻根系结构与杂草竞争之间的联系；2)在杂草稻独立进化群体中鉴定籽粒破碎的遗传基础，并建立该性状进化稳定性的机制；3)确定美国杂草稻对稻瘟病（稻瘟病是水稻的主要真菌病原体）的不同抗逆性的遗传和生化基础。除了为研究界提供见解外，该项目还将通过生产和传播针对STEM职业中代表性不足的群体的遗传和教育资源，使利益相关者、STEM教育工作者和学生受益。该奖项反映了美国国家科学基金会的法定使命，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。

Weeds that infest crop fields are a primary factor limiting global agricultural productivity in the United States and globally. One of the most problematic weeds for rice production is weedy rice (Oryza sativa), a close relative of cultivated rice that infests rice fields and aggressively outcompetes crop cultivars. This research seeks to understand and characterize the genetic basis and origins of the traits that allow weedy rice to invade rice fields, reduce yields and contaminate harvests. Three key features of weedy rice growth and reproduction will be characterized: patterns of root system growth that allow the weed to outcompete rice for soil nutrients; the genetic and developmental basis of seed dispersal mechanisms that allow the weed to rapidly invade and proliferate in rice fields; and the differential resilience shown by the weed against rice blast, a common fungal disease of rice fields. In addition to providing key insights into the basis of competitiveness in weedy rice, the project will provide genetic resources to the rice research community, training opportunities for K-12 science teachers, and educational training experiences for students including hearing-disabled students, a minority group that is underrepresented in STEM careers.Weedy rice (Oryza sativa) is an aggressive weed of rice production areas worldwide. It has evolved multiple times independently through a process of 'de-domestication' (feralization) from cultivated rice. As such, this system provides a natural replicated experiment for studying the genetic mechanisms that underlie weediness traits and the extent to which these are constrained by genetic background. Prior work by the collaborating research team has established that weedy rice aggressively outcompetes its cultivated relatives due, in part, to three key features: altered root system architecture (critical for below-ground resource acquisition), highly shattering seed (conferring differential reproductive success and dispersal ability), and differential pathogen resistance (permitting a competitive advantage in US crop fields). This project will characterize each of these features of weedy rice competitiveness, with the following specific goals: 1) to determine the genetic basis of the root system architecture (RSA) that has evolved convergently with repeated origins of weedy rice, and establish the connection between weedy rice RSA and weed competition via differential nutrient uptake; 2) to identify the genetic basis of seed shattering in independently-evolved populations of weedy rice, and establish the mechanisms underlying the evolutionary lability of this trait; and, 3) to determine the genetic and biochemical bases underlying the differential resilience of US weedy rice to rice blast disease, a major fungal pathogen of rice. Beyond providing insights for the research community, the project will also benefit stakeholders, STEM educators and students through the production and dissemination of genetic and educational resources targeting groups underrepresented in STEM careers.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.