Source: UNIVERSITY OF WASHINGTON submitted to NRP
IMPROVING MULTIGENE CASSETTES IN PLANTS VIA GENETIC INSULATORS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
Reporting Frequency
Annual
Accession No.
1030129
Grant No.
2023-67012-39445
Cumulative Award Amt.
$225,000.00
Proposal No.
2022-09700
Multistate No.
(N/A)
Project Start Date
Apr 1, 2023
Project End Date
Mar 31, 2026
Grant Year
2023
Program Code
[A1141]- Plant Health and Production and Plant Products: Plant Breeding for Agricultural Production
Recipient Organization
UNIVERSITY OF WASHINGTON
4333 BROOKLYN AVE NE
SEATTLE,WA 98195
Performing Department
(N/A)
Non Technical Summary
Plant biotechnology is keyto developing foods, fuels, fabrics, and building materials that will help us adapt to and mitigate climate change. Plants can be engineered to resist drought and disease; to produce pharmaceuticals and other valuable bioproducts; and to replace industrial inputscurrently derived from petroleum.However, most genetically engineered plants currently suffer from a serious problem. Theversions of genes that we insert into plants often become "silenced"over time, so that they no longer produce anything useful. Moreover, it is very costly and time-consumingto "stack" multiple engineered traits into a single plant variety. If we could devise a way to transform plants with several genes at once, this would streamline the ability of American agriculturalcompanies to develop useful and profitable new crop varieties. Achieving that end is the focus of this research.The project seeks to discover genetic insulators, which are DNA sequences that lie in between genes to improve their behavior. Insulators have two main benefits. First, they ensure that genes are properly regulated, that is, turned on or off in the correct part(s) of the plant. Second, they serve as a genetic buffer,so that the genes produce a consistent productno matter where they are inserted in the genome. Wewill use next-generation DNA sequencing technology to screen many thousands of potential insulators. Using artificial intelligence techniques, we will build a computer model of insulation in plants. We will also test our designs in live plants over several generations to determine whether the insulator sequences perform as intended. If successful, this work will solve a longstanding issue in biotechnology, which in turn will benefit American companies, farmers, and consumers of staplecrops including corn, soy, and cotton. The project also funds hands-on training and mentorship forcollege students in the biological sciences, facilitating the development of a highly skilled agricultural workforce.
Animal Health Component
40%
Research Effort Categories
Basic
40%
Applied
40%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
20124101080100%
Goals / Objectives
The goal of this research is to improve the properties oftransgenic plants used in agricultural biotechnology. Specifically, the project seeks to discover genetic insulators, which are DNA sequences that lie between genes to ensure that genes do not become silenced when inserted into plants. Insulators also regulate gene expression, ensuring that genes are only expressed in desired tissue types, rather than being expressed throughout the plant. In order to find and use novel plant insulator sequences, the following objectives will be pursued:Use a massively parallel reporter assay called plant STARR-seq to screen thousands of insulator candidatesUse machine learning algorithms and in silico evolution to strengthen the insulator candidates identified in the screenValidate insulator candidates for their effect on protein expression using a dual luciferase assayMake stable transgenic plant lines containing the insulator sequences discovered in steps 1-3Test a known insulator from animals in a plant modelUse novel insulator sequences to build a transgene cassette carrying multiple genes
Project Methods
Efforts (research): A massively parallel reporter assay developed byour lab, known as plant STARR-seq, will be used to screeninsulator candidates. A relative of tobacco called Nicotiana benthamiana will serve as amodel organism. The bacterial vector Agrobacterium tumefaciens will be used to transfect plasmidDNA libraries containing thousands of insulator candidates intoplant leaves. Two days later, RNA will be extracted from infected leaves andused to make sequencing libraries for the Illumina NextSeq platform. Sequencing data will be analyzed to determine the strength of insulator candidates in parallel. We will repeat the experiment using protoplasts madefrom maize leaves (Zea mays).A machine learning model for insulators will be built using the sequencing data. We will performin silicoevolution on the candidate sequences to attempt to produce even stronger insulators than are found in nature. We will also make stable transgenic plants in the model speciesArabidopsis thaliana. This will test whether promising insulator candidates actually work when integrated into the plant genome. Lastly, we will use the best insulators discovered in these experiments to build a multigene cassette. This will include three different fluorescent reporter genes that are regulateddifferently in order to show expression in specific plant tissues. These reporter genes will beflanked by insulator sequences that will hopefully ensure that the genes are only expressed in the target tissue types.Efforts (career, mentorship, and public outreach):The project director will mentor undergraduate students majoring in biology throughout the performance period. Undergraduate helpers will assist with data collection and plant care responsibilities. The project director will also help teach a summer course for high schoolers on basic computer programming and molecular biology techniques. The project director will participate inpublic science outreach events in the form of a lecture series. The project director will publish papers and attend large plant biology conferences to make connections in academia and in the biotech industry.Evaluation (research): Goals will be achieved if at least one novel genetic insulator is identified via the approach described above. Success in developing stable transgenic plants will be evaluated by achieving lowvariance in reporter gene expression among multiple lines of plants carrying the same DNA insert. Success in the insulation of the multigene cassette will be evaluated by directly viewing the tissue specificity of each reporter gene. Success in communicating research results will be met by publishing at least one peer-reviewed publication and attending at least one talk at a national/internationalconference.Evaluation (career, mentorship, and outreach):Success in translating the research to American agriculturewill be marked by meeting with at least one representative from a leading agriculture company to discuss the commercialization potential of the research. Career success will be achieved if the project director obtains an employment offer from a university or biotechnology company.Teaching and mentorship goals will be achieved if at least one undergraduate student graduates in biological science after working in the lab. Public outreach goals will be achieved if at least 50members of the public attend one or more of the lecture series at which I present.

Progress 04/01/24 to 03/31/25

Outputs
Target Audience:Our target audience is graduate and undergraduate students in the biological sciences,postdoctoral researchers and professors at institutions throughout the US, and professionals in the agricultural and biotechnology industry. All of these groups benefit from the scientific knowledge generated by this work. Changes/Problems:Cloning the DNA libraries took longer than expected, which delayed the large sequencing experiment and subsequent analyses. We also felt the need to conduct a follow-up sequencing experiment to test some exciting leads, which pushed back the generation of transgenic plants somewhat. Despite these problems we are confident that the work is proceeding largely as planned. What opportunities for training and professional development has the project provided?The Project Director trained/mentoredan undergraduate student intern during 2024.The student is of Native American origin. He isa biology major at Fort Lewis College in Durango, Colorado, which is a primarily undergraduate-serving institution with many economically disadvantaged minority students. The student was trained in both laboratory and computational techniques. Several important professional development events occurred in 2024. First, the Project Director presented a talk at theUSDA-NIFA Project Directors Meeting. After the talk, the PD established relationships with academic faculty members, which led to discussion of academic job opportunities. Taking place just after the NIFA meeting was theNational Association for Plant Breeding annual meeting. The project director presented a poster and won the poster competition. Several industry connections were made, leading to the Project Director presenting a special seminar at Bayer Crop Sciences twomonths later. Correspondence with Bayer is ongoing. How have the results been disseminated to communities of interest?Results were disseminated toacademic faculty from across the US via an oral presentation at the NIFA Project Directors Meeting. Results were shared with graduate students, postdocs, plant breeders, and industry professionals via a poster presentation at the National Association for Plant Breeding annual meeting. Results were also shared in an hour-long special seminar organized by Bayer Crop Sciences, which approximately 60 people attended. Results were written up as a manuscript submitted for publication in the journal The Plant Cell. What do you plan to do during the next reporting period to accomplish the goals?We will continue working on aims 4, 5, and 6 above. Work is underway to perform a sequencing experiment following up on leads generated in the first large screening experiment. We also plan to create additional transgenic plants to test hypotheses related to the biochemical mechanisms involved in insulation.

Impacts
What was accomplished under these goals? So far, we accomplished Goals 1, 2, and 3 under the major goals listed above. We successfully performed a large experiment screening ~180,000 DNA sequences and found hundreds of promising genetic insulator candidates. Using machine learning tools, we developed a software model for genetic insulation basedon the results. We created stable transgenic plants carrying insulator DNA fragments and confirmed their activity.

Publications


    Progress 04/01/23 to 03/31/24

    Outputs
    Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The Project Director received hands-on training in conducting a massively parallel reporter assay, which is a state-of-the-artR&D tool in both academic and industrial biotechnologysettings. The PD also learned many computational and statistical tools usingthe R programming language. Lastly, the PD acquired improved skillin maize protoplasting, a specializedtechnical protocol. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We willaddress the next several goals enumerated in the list above. Specifically, we will validate someof the 1,500 insulator candidate sequences usinga protein expression system, and begin designing multigene cassettes.Now that the PD has obtained and analyzed a dataset, we will begin to present the results at upcoming conferences such as the American Society of Plant Biologists meeting.

    Impacts
    What was accomplished under these goals? Of the objectives enumerated above, wemade significant progress on #1 and #2 during thereporting period. Plant STARR-seq was used to screen 180,000 insulator sequence candidates in tobacco plants.We analyzed the data and found approximately 1,500 sequences that appear to function as enhancer-blocking insulators, i.e., they selectively restrict gene expression, yet do not inhibit gene expression generally. This was the most important aim of the project: to find novel insulator sequences in plants.Wealsomade progress building a statstical/conceptualmodel for predicting insulator strength. We found DNA sequence motifs that are commonly found in the novel insulators, as well as predicted protein factors that may be involved in the insulation mechanism.

    Publications