Source: UNIVERSITY OF CALIFORNIA, DAVIS submitted to
PHYSIOLOGY OF CHILLING TOLERANCE IN TOMATO
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0214546
Grant No.
2008-35100-04459
Project No.
CA-D-PLS-7812-CG
Proposal No.
2008-01029
Multistate No.
(N/A)
Program Code
56.0B
Project Start Date
Aug 1, 2008
Project End Date
Jul 31, 2012
Grant Year
2008
Project Director
Bloom, A.
Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Performing Department
PLANT SCIENCES
Non Technical Summary
Tomato cultivars wilt if exposed to low root temperatures. Under the same conditions, chilling-tolerant wild relatives do not wilt. In progeny between cultivars and wild species, this trait was strongly associated with a genetic material from the wild species at a specific location on chromosome 9 (stm9). The physiological basis for this differential response is behavior of leaf stomata. Root water movement in all species declines severely as root temperatures fall. Cultivars keep their stomata open and transpire unabated until their leaves become flaccid and suffer permanent damage. Genotypes with the wild allele at stm9 rapidly close their stomata and remain undamaged. Reciprocal root-shoot grafts between differing genotypes show that roots and shoots contribute equally to this response. Our objective is to examine the physiology of stomatal control by stm9. Our approach is to 1)Determine if the stm9 region contains different loci controlling root versus shoot components through characterizing stomatal behavior of root-shoot grafts between contrasting genotypes. 2 Conduct field experiments to assess chilling tolerance of stm9 recombinants. 3)Identify compounds in tomato xylem sap that vary only in chilling-tolerant genotypes exposed to chilling root temperatures. We will add these compounds to artificial xylem sap, feed the sap to detached leaves, and monitor stomatal behavior. 4)Assess changes in these compounds under root chilling in chilling-tolerant and ‑sensitive varieties of other crops such as maize. Our goals, like those of the USDA program, are to characterize genes and mechanisms that contribute to temperature and drought tolerance in crops.
Animal Health Component
20%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2031460102045%
2031460100035%
2031530102010%
2031510102010%
Goals / Objectives
The proposed research on the physiological bases of chilling tolerance will contribute toward development of tomato cultivars capable of an extended growing season as well as provide a framework for improving other chilling- and drought-sensitive crops. Previously, we discovered that chilling sensitive and chilling-tolerant tomato genotypes differed in their ability to maintain shoot turgor when their roots were chilled to below 6 degrees because of distinct stomatal behavior. A quantitative trait loci (QTL) on chromosome 9 (stm9; shoot turgor maintenance) had the largest phenotypic effect on this trait. We used recombinant sub-NILs (near-isogenic lines) to fine-map stm9 to within a 2.7 cM region. The proposed experiments will examine sub-NILs that differ for allelic combinations at stm9 to explore the effect of this QTL on phenotype. Shoot turgor maintenance under root chilling results from stomatal behavior that avoids water stress. Thus, the sub-NILs should serve like temperature-sensitive mutants in identifying signals for stomatal behavior and advance the study of water relations in crop plants. This research will address fundamental issues in crop responses to abiotic stress as well as will develop valuable plant material that should prove useful in subsequent breeding efforts.
Project Methods
The proposed research will test the following hypotheses: 1. Recombinants containing the stm9 allele from wild species are more chilling tolerant in the field. 2. The stm9 region contains different loci controlling root versus shoot components. These are evident in the stomatal behavior of root-shoot grafts between contrasting genotypes. 3. Root signal compounds appear in the xylem sap only in chilling-tolerant genotypes exposed to chilling root temperature. Adding these compounds to artificial xylem sap and feeding the sap to detached leaves causes stomatal closure. 4. These compounds are also active in controlling stomatal behavior in chilling-tolerant varieties of other species such as maize.

Progress 08/01/08 to 07/31/12

Outputs
OUTPUTS: I am working with several national groups on these projects including the Council of Environmental Deans and Directors, the National Council for the Environment and Science, the American Indian Higher Education Consortium, and National Center for Atmospheric Research to develop a national undergraduate curriculum on Global Climate Change and Plant Physiology and Mineral Nutrition. I have been a major contributor and a member of the editorial board of the Encyclopedia of Earth, a public website that receives an average of 40,000 views each day. I have also given presentations to national organizations and major corporations including Association for Environmental Studies and Sciences, America Geophysical Union, Arcadia Biosciences, Environmental Defense Fund, Keygene, National Association of Environmental Professionals, and Society for Advancement of Chicanos and Native Americans in Science. I have presented keynote speeches at the Gordon Conference in Les Diablerets, Switzerland and International Conference on Plant Growth, Nutrition and Environment Interactions in Vienna, Austria. I developed public websites on this work at http://www.plantsciences.ucdavis.edu/plantsciences_Faculty/Bloom/Stre ss/main.html and at http://www.camelclimatechange.org/. I presented one of the first online courses to receive University of California credit; all the materials for this course on Climate Change are available for free on the Encyclopedia of Earth, and participants can receive "badges" acknowledging their achievement. I participated in a week-long workshop on communicating science to the media organized by the Heinz Center. I appeared on a podcast for Science magazine, local TV news, and several interviews on public radio. I wrote several press releases for the media and articles for lay journals. PARTICIPANTS: Hsien Ming Easlon, Lesley Randall, Dina St. Clair, Eli Carlisle, Brian Hua, Francesca Pinchevsky, Rachel Fichman, Amy Klein, Lucas Smith, and Jose Salvador Rubio Asensio, all of UC Davis have worked on the project. TARGET AUDIENCES: This project will influence anyone who grows or studies plants. We have made major advances in understanding the responses of plants to drought, chilling stress, rising levels of atmospheric CO2, and root-shoot communications. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Professor Dina St. Clair and I have examined the genetic and physiological bases for the differential chilling sensitivity of Solanum species. We found that the shoots of cultivated tomatoes and wild relatives from low altitudes wilt if their roots are exposed to chilling temperatures of around 5 degrees C. Under the same treatment, wild relatives from high altitudes maintain shoot turgor. The physiological basis for the differential response is stomatal behavior. Root hydraulic conductance in all species declines severely as root temperatures fall. Despite diminished water flow from the roots, cultivated tomato keeps its stomata open and transpires unabated until its leaves lose so much water that they become flaccid and suffer permanent damage. By contrast, the wild relatives from high altitudes close their stomata as water flow from the roots diminishes, and their leaf water potential remains relatively constant during a chilling episode. This trait (shoot turgor maintenance under root chilling) was associated with a quantitative trait locus (QTL) on chromosome 9 (stm9). Near-isogenic lines (NILs) were used to map stm9 within a 2.7 cM region. Grafts between the shoots of one genotype and the roots of another demonstrate that this response depends mostly on a root component. We also assessed this trait in introgression lines (ILs) containing segments collinear to the QTL stm9 region from either a) chilling-tolerant S. habrochaites, b) chilling- or c) drought-tolerant S. lycopersicoides, or d) drought-tolerant S. pennellii in a genetic background of cultivated tomato. S. habrochaites and S. lycopersicoides and their ILs maintained greater shoot turgor under root chilling than the cultivated tomato parents suggesting that adaptation to cold temperatures in wild tomatoes may involve similar gene(s). Drought adapted S. pennellii did not maintain turgor during root chilling suggesting responses to soil drought in S. pennellii are distinct from responses to chilling- induced rapid onset water stress. Feeding shoots of a wilting (chilling-sensitive) NIL for stm9 with xylem sap from a non-wilting (chilling-tolerant) NIL subjected to rhizosphere chilling induced stomatal closure, whereas feeding either NIL xylem sap from a non-wilting NIL under warm rhizosphere temperatures or from a wilting NIL did not influence stomatal behavior. This result demonstrates that some component of the xylem sap from a non-wilting NIL serves as a signal of rhizosphere chilling. Metabolic analysis of xylem sap and responses of shoots to artificial xylem sap amended with various substances implicate n-acylethanolamine production of roots as a key component.

Publications

  • Bloom AJ, Burger M, Asensio JSR, Cousins AB (2010) Carbon dioxide enrichment inhibits nitrate assimilation in wheat and Arabidopsis. Science 328: 899-903.
  • Bloom AJ (2010) Energetics of nitrogen acquisition. In: Foyer C, Zhang H (eds) Nitrogen Metabolism plants in the Post-Genomic Era. Vol. 2: Whole plant perspectives of nitrogen metabolism and network signalling processes in plants. Blackwell, Chichester UK, pp. 63-82.
  • Bloom AJ, Asensio JSR, Randall L, Rachmilevitch S, Cousins AB, Carlisle EA (2012) CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants. Ecology 93:355-367.
  • Bloom AJ, Randall L, Taylor AR, Silk WK (2012) Deposition of ammonium and nitrate in the roots of maize seedlings supplied with different nitrogen salts. Journal of Experimental Botany 63:1997-2006.
  • Bloom AJ (2012) Integrated whole organism physiology. In: Hastings A, Gross L (eds) Encyclopedia of Theoretical Ecology. UC Press, Berkeley, CA, pp. 376-381.
  • Bloom AJ (2009) Responses of crop plants to rising atmospheric carbon dioxide concentrations. California Agriculture 63:67-72.
  • Foyer CH, Bloom AJ, Queval G, Noctor G (2009) Photorespiratory metabolism: genes, mutants, energetics, and redox signaling. Annual Review of Plant Biology 60:455-484.
  • Volder A, Anderson LJ, Smart DR, Bloom AJ, Lakso AN, Eissenstat DM (2009) Estimating nitrogen uptake of individual roots in container- and field-grown plants using a 15N-depletion approach. Functional Plant Biology 36:621-628.
  • Bloom AJ (2010) Global Climate Change: Convergence of Disciplines. Sinauer Assoc., Sunderland, MA, 420 pp.
  • Bloom AJ (2010) Chapter 5. Mineral Nutrition. In: Taiz L, Zeiger E (eds) Plant Physiology, 5th Edition. Sinauer Assoc., Sunderland, MA. pp. 107-130.
  • Bloom AJ (2010) Chapter 12. Assimilation of Mineral Nutrients. In: Taiz L, Zeiger E (eds) Plant Physiology, 5th Edition. Sinauer Assoc., Sunderland, MA. pp. 341-368.


Progress 08/01/10 to 07/31/11

Outputs
OUTPUTS: I am working with several national groups on these projects including the Council of Environmental Deans and Directors, the National Council for the Environment and Science, the American Indian Higher Education Consortium, and National Center for Atmospheric Research to develop a national undergraduate curriculum on Global Climate Change and Plant Physiology and Mineral Nutrition. I have been a major contributor and a member of the editorial board of the Encyclopedia of Earth, a public website that receives an average of 40,000 views each day. I have also given presentations to national organizations and major corporations including America Geophysical Union, Society for Advancement of Chicanos and Native Americans in Science, Arcadia Biosciences, and Keygene. I have presented keynote speeches at the Gordon Conference in Les Diablerets, Switzerland and International Conference on Plant Growth, Nutrition and Environment Interactions in Vienna, Austria. I developed public websites on this work at http://www.plantsciences.ucdavis.edu/plantsciences_Faculty/Bloom/Stre ss/main.html and at http:// http://www.camelclimatechange.org/. I prepared one of the first online courses that will receive University of California credit; all the materials for this course on Climate Change are available for free on the Encyclopedia of Earth, and participants can receive "badges" acknowledging their achievement. PARTICIPANTS: Hsien Ming Easlon, Lesley Randall, Dina St. Clair, Eli Carlisle, and Jose Salvador Rubio Asensio, all of UC Davis have worked on the project. TARGET AUDIENCES: This project will influence anyone who grows or studies plants. We have made major advances in understanding the responses of plants to drought, chilling stress, and rising levels of atmospheric CO2. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Professor Dina St. Clair and I have examined the genetic and physiological bases for the differential chilling sensitivity of Solanum species. We found that the shoots of cultivated tomatoes and wild relatives from low altitudes wilt if their roots are exposed to chilling temperatures of around 5 degrees C. Under the same treatment, wild relatives from high altitudes maintain shoot turgor. The physiological basis for the differential response is stomatal behavior. Root hydraulic conductance in all species declines severely as root temperatures fall. Despite diminished water flow from the roots, cultivated tomato keeps its stomata open and transpires unabated until its leaves lose so much water that they become flaccid and suffer permanent damage. By contrast, the wild relatives from high altitudes close their stomata as water flow from the roots diminishes, and their leaf water potential remains relatively constant during a chilling episode. This trait (shoot turgor maintenance under root chilling) was associated with a quantitative trait locus (QTL) on chromosome 9 (stm9). Near-isogenic lines (NILs) were used to map stm9 within a 2.7 cM region. Grafts between the shoots of one genotype and the roots of another demonstrate that this response depends most heavily on a root component. Feeding shoots of a wilting (chilling-sensitive) NIL for stm9 with xylem sap from a non-wilting (chilling-tolerant) NIL subjected to rhizosphere chilling induced stomatal closure, whereas feeding either NIL xylem sap from a non-wilting NIL under warm rhizosphere temperatures or from a wilting NIL did not influence stomatal behavior. This result demonstrates that some component of the xylem sap from a non-wilting NIL serves as a signal of rhizosphere chilling. Metabolic analysis of xylem sap and responses of shoots to artificial xylem sap amended with various substances implicate n-acylethanolamine production of roots as a key component.

Publications

  • Bloom AJ, Asensio JSR, Randall L, Rachmilevitch S, Cousins AB, Carlisle EA (2012) CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants. Ecology http://dx.doi.org/10.1890/11-0485.1.
  • Bloom AJ, Randall L, Taylor AR, Silk WK (2012) Deposition of ammonium and nitrate in the roots of maize seedlings supplied with different nitrogen salts. Journal of Experimental Botany DOI:10.1093/jxb/err410.
  • Bloom AJ (2012) Integrated whole organism physiology. In: Hastings A, Gross L (eds) Encyclopedia of Theoretical Ecology. UC Press, Berkeley, CA, in press.


Progress 08/01/09 to 07/31/10

Outputs
OUTPUTS: I have written major sections of the standard textbooks on Plant Physiology, Plant Mineral Nutrition, and Global Climate Change and have become involved in developing national curricula for these disciplines. I am working with several national groups on these projects including the Council of Environmental Deans and Directors and the National Council for the Environment and Science. I have been a major contributor to several public web sites including the Encyclopedia of Earth and Plant Physiology Online. I have also given presentations to local, state, and federal governmental agencies as well as major universities including Harvard, Yale, Texas A&M, Cornell, Middlebury College, U. of Vermont, Central Vermont Planning Commission, and Governor's Global Climate Summit, and UC Davis Alumni Association. I have presented keynote speeches at the Gordon Conference in Les Diablerets, Switzerland, Environmental Defense Fund Annual Science Day, CEDD Annual Conference, and two sessions of the 16th International Plant Nutrition Colloquium. I reviewed educational materials for the Climate Literacy and Energy Awareness Network, grant proposals for USDA Competitive Grants Program, and NSF panels. I was an invited participant in Science Communication & Policy Development Workshop, Heinz Center. I developed a public web site on this work at http://www.plantsciences.ucdavis.edu/plantsciences_Faculty/Bloom/Stre ss/main.html. PARTICIPANTS: Hsien Ming Easlon, Lesley Randall, Dina St. Clair, Eli Carlisle, Jose Salvador Rubio Asensio, Brian Hua, and Francesca Pinchevsky all of UC Davis have worked on the project. TARGET AUDIENCES: This project will influence anyone who grows or studies plants. We have made major advances in understanding the responses of plants to drought and to chilling stress PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
This research will address fundamental issues in crop responses to abiotic stress and provide insights about the process of domestication as well as will develop valuable plant material that should prove useful in subsequent breeding efforts. The tomato genotypes that we have developed should serve like temperature-sensitive mutants in identifying signals for stomatal behavior and advance the study of water relations in crop plants. Using the metabolomics facility at Iowa State, we have found that only four compounds in the xylem sap change between chilling tolerant and intolerant genotypes under root chilling. Two of these compounds produce stomatal closure when fed to the leaves in artificial xylem sap. In the field, the chilling-tolerant genotype experiences smaller fluctuations in water potential under drought than the chilling-sensitive genotype. Part of this response derives from more rapid stomatal closure at certain times of the day, part derives from different root properties. Chilling tolerance confers increased tolerance to salinity and to fungal infection. We have developed a number of new techniques that permit assessment of the nitrogen isotopic signatures of nitrate and nitrite and the assessment in situ of ammonium versus nitrate use by crops.

Publications

  • Bloom, A. J. (2009) As carbon dioxide rises, food quality will decline without careful nitrogen management. California Agriculture 63:67-72.
  • Bloom, A. J. (2010) Energetics of nitrogen acquisition. In: Nitrogen Metabolism in Plants in the Post-Genomic Era. Vol. 2: Whole plant perspectives of nitrogen metabolism and network signalling processes in plants, Foyer, C. and H. Zhang, eds. Blackwell, Chichester, UK. pp. 63-82.
  • Bloom, A. J. (2010) Global Climate Change: Convergence of Disciplines, Sinauer Assoc., Sunderland, MA.
  • Bloom, A. J., M. Burger, J. S. R. Asensio, and A. B. Cousins (2010) Carbon dioxide enrichment inhibits nitrate assimilation in wheat and Arabidopsis. Science 328:899-903 DOI:10.1126/science.1186440.
  • Foyer, C. H., A. J. Bloom, G. Queval, and G. Noctor (2009) Photorespiratory metabolism: Genes, mutants, energetics, and redox signaling. Annual Review of Plant Biology 60:455-484.
  • Bloom, A. J. (2010) Chapter 5: Mineral Nutrition. In: Plant Physiology, 5th Edition, Taiz, L. and E. Zeiger, eds. Sinauer Assoc., Sunderland, MA. pp. 107-130.
  • Bloom, A. J. (2010) Chapter 12: Assimilation of Mineral Nutrients. In: Plant Physiology, 5th Edition, Taiz, L. and E. Zeiger, eds. Sinauer Assoc., Sunderland, MA. pp. 341-368.


Progress 08/01/08 to 07/31/09

Outputs
OUTPUTS: I have written major sections of the standard textbooks on Plant Physiology, Plant Mineral Nutrition, and Global Climate Change and have become involved in developing national curricula for these disciplines. I am working with several national groups on these projects including the Council of Environmental Deans and Directors and the National Council for the Environment and Science. I have been a major contributor to several public web sites including the Encyclopedia of Earth and Plant Physiology Online. I have also given presentations to local, state, and federal governmental agencies as well as major universities including Harvard, Texas A&M, and Cornell. PARTICIPANTS: Hsien Ming Easlon, Lesley Randall, Dina St. Clair, Eli Carlisle, Jose Salvador Rubio Asensio, Brian Hua, Francesca Pinchevsky, and Anthony Fisher, all of UC Davis have worked on the project. TARGET AUDIENCES: This project will influence anyone who grows or studies plants. We have made major advances in understanding the responses of plants to rising levels of atmospheric carbon dioxide and to chilling stress. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The results on nitrogen source and assimilation provide a new perspective on the role of photorespiration in plant metabolism and the response of plants to rising atmospheric levels of carbon dioxide. They predict that plants which are reliant upon nitrate as a nitrogen source will become more nitrogen limited as carbon dioxide levels increase. Such plants will be at a competitive disadvantage in comparison to those which are reliant on ammonium as a nitrogen source. To enhance agricultural productivity in the future, we should try to develop crops that are less susceptible to ammonium toxicity and to develop additional approaches to inhibit nitrification, the conversion of ammonium to nitrate by soil microbes. For example, the decline in sugar maple (Acer saccharum) throughout North America is usually attributed to acid rain and nutrient imbalances, although the supporting evidence is inclusive. Sugar maple is unique among hardwoods because it occupies soils that have high rates of nitrate production. In our experiments, carbon dioxide enrichment strongly repressed the growth of sugar maples receiving nitrate nutrition. The decline of this species, therefore, may derive from rising carbon dioxide levels. In the other part of the project, The tomato genotypes that we have developed should serve like temperature-sensitive mutants in identifying signals for stomatal behavior and advance the study of water relations in crop plants. This research will address fundamental issues in crop responses to abiotic stress and provide insights about the process of domestication as well as will develop valuable plant material that should prove useful in subsequent breeding efforts. We have developed a number of new techniques that permit assessment of the nitrogen isotopic signatures of nitrate and nitrite and the assessment in situ of ammonium versus nitrate use by crops.

Publications

  • Volder A, Anderson LJ, Smart DR, Bloom AJ, Lakso AN, Eissenstat DM (2009) Estimating nitrogen uptake of individual roots in container- and field-grown plants using a 15N-depletion approach. Functional Plant Biology 36:621-628.
  • Bloom AJ (2009) Global Climate Change: Convergence of Disciplines. Sinauer Assoc., Sunderland, MA, 420 pp.
  • Bloom AJ (2009) Energetics of nitrogen acquisition. In: Foyer C. and Zhang, H. (eds) Nitrogen Metabolism plants in the Post-Genomic Era. Vol. 2: Whole plant perspectives of nitrogen metabolism and network signalling processes in plants. Blackwell, Chichester UK, in press.
  • Bloom AJ (2009) Chapter 5. Mineral Nutrition. In: Taiz L, Zeiger E (eds) Plant Physiology, 5th Edition. Sinauer Assoc., Sunderland, MA. in press.
  • Bloom AJ (2009) Chapter 12. Assimilation of Mineral Nutrients. In: Taiz L, Zeiger E (eds) Plant Physiology, 5th Edition. Sinauer Assoc., Sunderland, MA. in press.