Source: UNIVERSITY OF CALIFORNIA, DAVIS submitted to
INFLUENCE OF NITROGEN FORM ON WHEAT CARBON FIXATION, GRAIN YIELD, AND PROTEIN YIELD
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
EXTENDED
Funding Source
Reporting Frequency
Annual
Accession No.
1011273
Grant No.
2017-67007-25930
Project No.
CA-D-PLS-2370-CG
Proposal No.
2016-06702
Multistate No.
(N/A)
Program Code
A1142
Project Start Date
Nov 1, 2016
Project End Date
Oct 31, 2018
Grant Year
2018
Project Director
Bloom, A. J.
Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Performing Department
Plant Sciences
Non Technical Summary
Overall goal: Rising atmospheric CO2 levels inhibit the conversion of nitrate into amino acids in wheat and compromise grain protein yields. Unfortunately, relatively little is known about wheat performance under ammonium nutrition. This research will determine the influence of CO2 concentration and nitrate and ammonium as nitrogen sources on wheat carbon fixation, grain yield, and protein yield, and the genetic bases of these responses.Supporting objectives: (a) To assess the balance between wheat nitrate and ammonium assimilation and its effects on carbon and protein deposition under elevated CO2. (b) To exploit the natural variation among wheat genotypes and new genetic tools for identifying loci and candidate genes associated with the differences in performance under ammonium nutrition and elevated CO2.Plans: A team of wheat physiologists and geneticists will (1) establish the range of ammonium tolerance among diverse wheat genotypes and conduct a GWAS to identify loci associated with this trait; (2) examine patterns of carbon fixation and deposition and nitrogen allocation under ambient and elevated CO2 in genotypes that show large differences in ammonium tolerance; (3) cross-validate major GWAS loci using QTL mapping in bi-parental segregating populations of recombinant inbred lines; (4) validate candidate genes using a sequenced population of TILLING mutants.Relevance: This research will improve the productivity and nutritional quality of wheat under the conditions anticipated in the near future. It addresses Program Area Priority Code A1141: "lead to a better understanding of how nitrogen supply brings about patterns of carbon fixation and deposition."
Animal Health Component
0%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1021549101060%
1021549108040%
Goals / Objectives
The overall goal is to improve the productivity and nutritional quality of crops in the face of climate change. This research on wheat will determine the influence of inorganic nitrogen (N) form, nitrate (NO3-) vs. ammonium (NH4+), and atmospheric carbon dioxide (CO2) concentration on carbon fixation, grain yield, and protein yield, and the genetic bases of these responses. Thus, it will address Program Area Priority Code A1142: "include discoveries that lead to a better understanding of how nitrogen supply brings about patterns of carbon fixation and deposition."The short-term goals are to examine wheat responses to NH4+. Wheat breeding in United States has focused almost entirely on yield responses to NO3- nutrition because NO3- is the dominant N source in temperate agricultural soils. Relatively little is known about the yield responses of wheat receiving NH4+ nutrition. Rising atmospheric CO2 concentration inhibits the conversion of NO3- into protein in the shoots of wheat and other C3 plants and limits wheat protein yields. By contrast, such changes in CO2 have little effect on NH4+ conversion into protein. Therefore, managing N supply to balance soil NO3- and NH4+ availability and shifting wheat from NO3- to NH4+ as an N source will become a major bottleneck to grain production and quality. This project will examine diverse wheat lines receiving NO3- or NH4+ nutrition under ambient or elevated CO2 atmospheres to identify loci and candidate genes associated with higher grain yield and protein yield under the environmental conditions anticipated in the near future.
Project Methods
Establish the range of NH4+ tolerance for wheat genotypes in the National Small Grain Core Collection (NSGCC) and conduct a genome wide association study (GWAS) to identify loci associated with NH4+ tolerance under ambient and elevated CO2.Determine patterns of carbon fixation and deposition and nitrogen allocation under ambient and elevated CO2 in diverse genotypes, including those that show large differences in NH4+ tolerance. Characterize NO3- vs. NH4+ responsive physiological parameters in the genotypes that show large differences in the patterns of carbon fixation and deposition and nitrogen allocation. Cross-validate major GWAS loci using quantitative trait loci (QTL) mapping in bi-parental populations. Identify candidate genes and validate them using sequenced population of TILLING (Targeting Induced Local Lesions in Genomes) mutants in tetraploid wheat.

Progress 11/01/16 to 10/31/17

Outputs
Target Audience:We have targeted researchers and breeders from academia, governments, NGOs, and industry who are working on wheat and other small grains. To reach this targeted audience, we made presentations at NIFA-IWYP Project Director meeting on January 15, 2017 at Plant and Animal Genome Conference in San Diego, the Annual IWYP Science Program Conference held in Obregon, Mexico in conjunction with CIMMYT on March 19 - 24, 2017, and the Plant Science Central meeting in Palmerston North, New Zealand on July 4 - 6, 2017. We also published all the data from Wheat FACE project conducted in Maricopa, AZ and have published a review on wheat responses to elevated CO2. Changes/Problems:We have interviewed several candidates for the postdoc positions funded by this project, but have yet to find suitable persons. We are continuing the search. One candidate seems promising and will visit the laboratory in the near future. What opportunities for training and professional development has the project provided?Porpipat Kasemsap, a graduate student from Thailand with a Fullbright Scholarship, has directed a team of four UC Davis undergraduates to conduct the screens of ammonium tolerance in spring wheat. Shuping Xiong, a visiting professor from Nanjing Agricultural University, China, has been also participating for the last few months. How have the results been disseminated to communities of interest?We have made presentations at NIFA-IWYP Project Director meeting on January 15, 2017 at Plant and Animal Genome Conference in San Diego, the Annual IWYP Science Program Conference held in Obregon, Mexico in conjunction with CIMMYT on March 19 - 24, 2017, and the Plant Science Central meeting in Palmerston North, New Zealand on July 4 - 6, 2017. We also published all the data from Wheat FACE project conducted in Maricopa, AZ and have published a review on wheat responses to elevated CO2. What do you plan to do during the next reporting period to accomplish the goals?We are currently repeating the screens of ammonium tolerance in spring wheat under ambient and elevated CO2 atmospheres in greenhouses and controlled environmental chambers. We are continuing development of portable, ultra-high resolution oxygen analyzer for assessing wheat ammonium vs. nitrate assimilation in the field.

Impacts
What was accomplished under these goals? We have conducted an thorough screen of ammonium tolerance in 875 accessions of spring wheat under ambient CO2 atmospheres and analyzed the results with a Genome-Wide Association Study (GWAS). Growth of the accessions under high ammonium ranged from 50% to 130% of growth under low ammonium; growth of the accessions under low nitrate ranged from 50% to 150% of growth under low ammonium. This variances were consistent over five replications. Certain loci were significantly associated with these phenotypes. We are continuing development of a portable, ultra-high resolution oxygen analyzer for assessing non-destructively wheat ammonium vs. nitrate assimilation in the field.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Rubio-Asensio, J. S. and A. J. Bloom (2017) Inorganic nitrogen form: a major player in wheat and Arabidopsis responses to elevated CO2. Journal of Experimental Botany 68:2611-2625.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Kimball, B. A., P. J. Pinter Jr, R. L. LaMorte, S. W. Leavitt, D. J. Hunsaker, G. W. Wall, F. Wechsung, G. Wechsung, A. J. Bloom, and J. W. White (2017) Data from the Arizona FACE (Free-Air CO2 Enrichment) experiments on wheat at ample and limiting levels of water and nitrogen. Open Data Journal for Agricultural Research 3.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Bloom, A. J. and P. Kameritsch (2017) Relative association of Rubisco with manganese and magnesium as a regulatory mechanism in plants. Physiologia Plantarum in press.
  • Type: Books Status: Published Year Published: 2017 Citation: Bloom, A. J. (2017) Climate Change: Causes, Consequences, and Solutions, Smithsonian Institution, Encyclopedia of Earth. https://indd.adobe.com/view/8f2ed4a1-a1b0-4f12-b5bb-5009bbbad0f3.