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

在美国和全球范围内，农田杂草是限制全球农业生产力的主要因素。水稻生产中最有问题的杂草之一是杂草水稻，它是栽培水稻的近亲，侵袭稻田，在竞争中咄咄逼人。这项研究试图了解和描述杂草水稻入侵稻田、减产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：允许杂草在土壤养分方面胜过水稻的根系生长模式；允许杂草在稻田中快速入侵和繁殖的种子传播机制的遗传和发育基础；以及杂草对稻瘟病表现出的不同韧性。稻瘟病是一种常见的稻田真菌疾病。除了提供对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社区提供遗传资源，为K-12科学教师提供培训机会，并为包括听力障碍学生在内的学生提供教育培训经验。听力障碍学生是STEM职业生涯中代表性不足的少数群体。杂草水稻是世界各地水稻产区的一种侵略性杂草。它通过栽培水稻的“去驯化”(发酵)过程独立进化了好几次。因此，这个系统为研究杂草性状背后的遗传机制以及这些遗传机制在多大程度上受到遗传背景的制约提供了一个自然的重复实验。合作研究小组先前的工作已经证明，杂草水稻在竞争上强于其种植的近亲，部分原因是三个关键特征：改变的根系结构(对地下资源获取至关重要)，高度粉碎的种子(赋予不同的繁殖成功和传播能力)，以及不同的病原菌抗性(允许在美国作物田里获得竞争优势)。本项目将描述杂草水稻竞争力的每一个特征，具体目标如下：1)确定与杂草水稻重复起源同步进化的根系构型(RSA)的遗传基础，并通过差异营养吸收在杂草水稻RSA和杂草竞争之间建立联系；2)确定杂草水稻独立进化群体中种子破碎的遗传基础，并建立这一性状进化不稳定的机制；以及3)确定美国杂草水稻对稻瘟病的不同适应性的遗传和生化基础。除了为研究界提供见解外，该项目还将通过制作和传播针对STEM职业生涯中代表性较低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NSF的法定使命，并通过使用基金会的智力优势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.