CHARACTERIZATION AND MECHANISMS OF PLANT RESPONSES TO OZONE IN THE U.S.

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0225475
• Multistate No.: NE-1030
• Project Start Date: Apr 1, 2011
• Project End Date: Sep 30, 2012
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF NEW HAMPSHIRE
51 COLLEGE RD SERVICE BLDG 107
DURHAM,NH 03824

Performing Department
Biological Sciences

Non Technical Summary
The proposed research will complement objectives 3 and 4 of the multistate project NE1030 in providing a unique dimension to the ongoing research on the joint effects of O3 with CO2 on crop growth and productivity, and delineating the physiological and molecular basis of O3 toxicity and tolerance in plants. The study will test our hypotheses of using polyamines and amino acids as biochemical indicators/markers of stress in plants and in their ability to help us monitor crop health. In addition, we propose to test if the cellular contents of these metabolites can be used to predict/correlate sensitivity/tolerance of various genotypes of a species to O3. The data obtained in our studies will be integrated with measurements of plant growth and yield parameters, hourly data on the ambient O3 concentrations and climate variables (radiation, temperature etc.). The participation of our lab in this research will contribute to several specific outputs and outcomes of the multistate project NE1030, such as: (i) Prediction of crop production changes over time, as a function of ongoing climate change, specifically related to O3 and CO2. Information will be useful to both public and private urban and industry planners. (ii) Information on the mechanisms of O3 toxicity and tolerance in plants and alterations in their functional physiology to O3 exposures will lead to the identification of genes that can mitigate the effects of O3 and other forms of oxidative stress. Once identified, these can be linked to expression levels in impacted ecosystems. (iii) Development and/or identification of tolerant cultivars and varieties for the production sector and documentation of the role of specific mechanistic adaptations to individual species fitness and ecosystem function. (iv) Development of new methodologies and derived information to establish relationships between O3 exposures and plant responses that would help regulatory agencies in making scientific knowledge-based policies about State and National Ambient Air Quality Standards for O3 to protect cultivated (crops) or managed (forests) and native vegetation (bio-diversity). (v) Improvement in understanding of regional and national scale issues in resource management.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
206	1510	1040	10%
206	1510	1020	10%
206	1549	1040	10%
206	1549	1020	10%
206	1820	1040	10%
206	1820	1020	10%
201	1510	1040	10%
201	1510	1020	10%
201	1820	1040	10%
201	1820	1020	10%

Knowledge Area
206 - Basic Plant Biology; 201 - Plant Genome, Genetics, and Genetic Mechanisms;

Subject Of Investigation
1510 - Corn; 1549 - Wheat, general/other; 1820 - Soybean;

Field Of Science
1040 - Molecular biology; 1020 - Physiology;

Keywords

ozone toxicity, carbon dioxide, polyamines, amino acids, putrescine,

spermidine, spermine, arginine decarboxylase, ornithine

decarboxylase, s-adenosylmethionine decarboxylase, spermidine,

spermine, glutamic acid, gamma aminobutyric acid, abiotic stress,

gene activity, quantitative reverse transcriptase polymerase chain

reaction, qrt-pcr,

Goals / Objectives
1.Examine the joint effects of O3 with other growth regulating factors (e.g., CO2, temperature) that are expected to vary with ongoing climate change on crop growth and productivity. 2.Examine the physiological and molecular basis of O3 toxicity and tolerance in plants. 3.Develop appropriate educational tools (including handouts, digital media, demonstration sites, distance education) and conduct advanced training for K-12 public school teachers, college level instructors, and outreach educators regarding the effects of ambient O3 pollution on plants.

Project Methods
We propose to analyze the cellular contents of the best-known biochemical markers/indicators of stress (i.e. polyamines, and selected amino acids like Pro, Arg, GABA and Glu) in contrasting groups of plant taxa (two legumes and a grass) in response to O3 and O3+CO2 treatment grown at various sites, including the well known SoyFACE site in Illinois. We will test our hypothesis that cellular metabolites can be used as reliable indicators and predictors of tolerance to certain types of abiotic stress, including O3. We will analyze enzyme activity and gene expression related specifically to the polyamine and related amino acid biosynthetic pathways. The activities of key polyamine biosynthetic enzymes (ADC, ODC and SAMDC) and those involved in the biosynthesis of Pro and Arg from Glu will be analyzed at several times following experimental treatments, and the expression of their respective genes will be analyzed by quantitative RT-PCR. The study sites will be located at IL (SoyFACE) and NC (Open Top chambers and controlled environment chambers for soybean, snap bean and wheat). All experimental treatments and planting sites will be the same as currently used by scientists involved in NE1030. Sampling for biochemical analyses will be done at least at three different times following treatments (with O3 and CO2).

Progress 04/01/11 to 09/30/12

Outputs
OUTPUTS: Ozone is a major environmental stressor of crop plants. In order to develop plants that are tolerant of ozone, we must understand the biochemical and physiological effects of ozone on plants and their interaction with the genetic background of plants. Dr. Kent Burkey (North Carolina) conducted experiments with several hybrids of soybean in open top chambers using O3 treatments of 25, 60, 90, and 120 ppb. The relationship between foliar injury and yield was reported by his group for several soybean plant introductions that are being used in studies to identify ozone tolerance mechanisms and map ozone tolerance genes. Fiskeby III was confirmed as the most tolerant genotype with the least foliar injury and no yield loss across the full range of O3 treatment, and Mandarin Ottawa was confirmed as a sensitive genotype for comparison. Another genotype, Fiskeby 840-7-3, was found to exhibit an intermediate response. Ozone treated material collected in these experiments was received at NHAES for analysis of polyamines. We analyzed the polyamines (putrescine, spermidine and spermine) in the foliage of the above introductions using modifications of our HPLC techniques. We found strong correlations between cellular polyamines and the tolerance of certain genotypes to ozone. PARTICIPANTS: Individuals: Julia Ong, Lin Shao, Maegan Gagnon, Dr. Kent Burkey, Dr. Fitzgerald Booker Dr. John Carlson Institutions: USDA-ARS Plant Science Research Unit, Raleigh, NC Pennsylvania State University, College Park, PA; USDA Forest Service, Durham, NH Training and professional development: undergraduate and graduate students, post-doctoral fellows, faculty, K-12 teachers, staff, and volunteers TARGET AUDIENCES: Target audience: scientists, undergraduate and graduate students, post-doctoral fellows, faculty, K-12 teachers and students, general public Efforts: formal classroom instruction, laboratory instruction, practicum experiences; development of laboratory course on techniques of plant physiology and biochemistry; internships; workshops; experiential learning opportunities; PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The results reveal that there is a strong correlation between cellular polyamines and stress tolerance in soybean ad it should be possible to use polyamines as potential biochemical indicators of (ozone) stress in different soybean genotypes. Large induction of polyamines (generally by 3- to 5-fold) was found to be a component of resistance to O3. Interestingly, we found that induction of <3-fold was not protective, but also that induction of >10-fold was also not protective. This remains to be explained, but is in line with some damaging effects of high putrescine seen in poplar cell cultures and Arabidopsis seen previously in our lab. We found that both low constitutive polyamines and a low level of induction by stress were characteristic of the O3 sensitive lines. Polyamines respond to diverse stresses, providing some protection, including drought, NH3, O3 and others, but are not effective as osmolytes They appear to stabilize membranes. We observed that low levels of constitutive polyamines are predictive in plants of susceptibility to stress.

Publications

• No publications reported this period