Ann PowellAssociate Research Biochemist |
My primary research interest is to understand the roles of enzymes and proteins in developing and ripening fruit. I have three major topics of research: 1. Identify functions in green fruit that can improve the pathgen resistance of red fruit . 2. Analyze the ftranscription factor function in tomato. 3. Characterize proteins and enzymes that modify the plant cell wall during fruit ripening. I work primarily with tomato and Arabidopsis but have also worked with strawberry and melons. I usually work with necrotrophic fungal pathogens and I use transgenic plants to investigate the functions of proteins and enzymes. I teach an undergraduate course on developing research ideas in a proposal format (BIT181) that is excellent preparation for a student who would like to work in a research lab, particularly for an Honors Thesis. I have taught an undergraduate lab course on techniques used in research in the plant sciences (BIT 161B).
Degrees:
1976 - PhD - University of Washington - Biochemistry
1971 - BA - Stanford University - Biological Sciences
Department and Center Affiliations:
Plant Sciences Department, Section Agricultural Plant Biology
Plant Genome Affiliation Group
Professional Societies:
Molecular Plant Microbe Interactions
Association of Plant Biologists
Association of Women in Sciences
Grad Group Affiliations and Specialties:
Plant Biology
Publications:
1. Vicente, A.R., Civello, P.M., Martinez, G.A., Powell, A.L.T., Labavitch J.M., Chaves, A.R. 2005. Control of postharvest spoilage in soft fruit. Stewart Postharvest Review 1 December, 2005. www.stewartpostharvest.com/December_2005/Vicente.pdf.
2. Rousseaux, M.C., Jones, C., Adams, D., Chetelat, R., Bennett, A., Powell, A. 2005. Genetic analysis of ascorbic acid, phenolic and antioxidant fruit QTL in Lycopersicon pennellii. Theoretical and Applied Genetics 111: 1396-1408.
3. Aguero, C.B., Uratsu, S.L., Greve, L.C., Powell, A.L.T., Labavitch, J.M., Meredith, C.P., Dandekar, A.M., 2005. Evaluation of tolerance to Pierce's Disease and botrytis in transgenic plants of Vitis vinifera L. expressing the pear PGIP gene. Mol. Plant Path. 6:43-51.
4. Stotz, Henrik U., Elad, Yigal, Powell, Ann L.T., Labavitch, John M. 2004. Chapter 20: "Innovative biological approaches to Botrytis suppression." In: Botrytis spp.: A comprehensive treatise. Kluwer Academic Publishers, The Netherlands. (Y. Elad, B. Williamson, P. Tudzynski, N. Delen, Eds.). Pp.369-392.
5. D'hallewin, G., Schirra, M., Powell, A.L.T., Greve, L.C., Labavitch, J.M. 2004. Properties of a polygalacturonase-inhibiting protein from 'Oroblanco' grapefruit. Physiologia Plantarum 120:395-404.
6. Kalamaki, M.S., Powell, A.L.T., Struijs, K., Labavitch, J.M., Reid, D.S., Bennett, A.B. 2003. Transgenic over-expression of expansin influences particle size distribution and improves viscosity of tomato juice and paste. J. Agricultural and Food Chem. 51:7465-7471.
7. Powell, A.L.T., Kalamaki, M.S., Kurien, P.A., Gurrieri, S., Bennett, A.B.. 2003. Simultaneous transgenic suppression of LePG and LeExp1 influences fruit texture and juice viscosity in a fresh market tomato variety. J. Ag. and Food Chemistry 51:7450-7455.
8. Thornburg, R., Carter, C., Powell, A., Horner, H.H., Rizhsky, L., Mittler, R.. 2003. A major function of the nectary gland is plant defense against microbial attack. Plant Syst. Evol. 238:211-218.
9. Powell, A.L.T. and A.B. Bennett. 2002. Chapter: "Tomato" In: Fruit and Vegetable Biotechnology. Woodhead Publishing Ltd., Cambridge, UK (V. Valpuest, Ed.). Pp 185-221.
10. Gurusinghe, S., Powell, A.L.T., Bradford, K.J. 2002. Enhanced expression of BiP is Associated with treatments that extend storage Longevity of primed tomato seeds. J. Amer. Soc. Hort. Sci. 127 (4): 528-534.
11. Powell, A.L.T., van Kan, J., ten Have A., Visser J., Greve L.C., Bennett A.B., Labavitch J.M. 2000. Transgenic expression of pear PGIP in tomato limits fungal colonization. Mol. Plant Microbe Interactions 13:942-950.
12. Civello, P.M., Powell, A., Sabehat A. and Bennett, A.B. 1999. An expansin gene expressed in ripening strawberry fruit. Plant Physiol. 121:1-7.
13. Kanayama, Y, Granot, D., Dai N, Petreikov, M, Schaffer, A., Powell, A. and Bennett, A.B. 1998. Tomato fructokinases exhibit differential expression and substrate regulation. Plant Physiol. 117:85-90.
14. Stotz, H.U., Contos, J.A., Powell, A.L.T., Bennett, A.B. and Labavitch, J.M. 1994. Structure and expression of an inhibitor of fungal polygalacturonases from tomato. Plant Mol. Biol. 25:607-617.
15. Powell, A.L.T., Stotz, H.U., Labavitch, J.M. and Bennett, A.B. 1995. Glycoprotein Inhibitors of Fungal Polygalacturonases. In: Advances in Molecular Genetics of Plant-Microbe Interactions, Vol. III. Kluwer Academic Publishers, Boston, MA (M.J. Daniels, J.A., Downie, A.E. Osborne, Eds.) pps. 399-402.
16. Stotz, H.U., Powell, A.L.T., Damon, S.E., Greve, L.C., Bennett, A.B. and Labavitch, J.M. 1993. Molecular characterization of a polygalacturonase inhibitor from Pyrus communis L. cv Bartlett. Plant Physiol. 102:133-138.
17. Kanemoto, R., Powell, A.L.T., Akiyoshi, D.E., Regier, D.A., Kerstetter, R.A., Nester, E.W., Hawes, M.C., Gordon, M.P. 1989. Nucleotide sequence and analysis of the plant-inducible locus pinF from Agrobacterium tumefaciens. J. of Bacteriology 171:2506-2512.
18. Powell, A.L.T. and Gordon, M.P. 1989. "Plant Tumor Formation." In: The Biochemistry of Plants: A Comprehensive Treatise. Vol. 15, Acad. Press, Orlando, Fl. (A. Marcus, Ed.) pp 617-651.
19. Amasino, R.M., Powell, A.L.T. and Gordon, M.P. 1984. Changes in T-DNA methylation and expression are associated with phenotypic variation and plant regeneration in a crown gall tumor line. Mol. Gen Genet. 197:437-446.
20. Gordon, M., Garfinkel, D., Klee, H., Knauf, V., Kwok, W., Lichtenstein C., McPherson J., Montoya, A., Nester, E., OHara, P., Powell, A., Ream L.W., Simpson, R., Taylor, B., and White, F. 1982. "Crown Gall - Nature's Genetic Engineer." In: From Gene to Protein: Translation into Biotechnology, Acad. Press, Inc., Orlando, Fl., pp.105-125.
21. Thomashow, M.F., Nutter, R., Postle, K., Chilton, M.D., Blattner, F.R., Powell, A., Gordon, M.P., Nester, E.W. 1980. Recombination between Higher Plant DNA and the Ti-plasmid of Agrobacterium tumefaciens. Proc. Natl. Acad. Sci. USA 77:6448-6452.
22. King, W., Thomas-Powell, A.L., Raab-Traub, N., Hawke, M. and Kieff, E. 1980. Epstein-Barr Virus RNA. V. Viral RNA in a restringently infected growth-transformed cell line. J. Virol. 36:506-518.
23. Kieff, E., Given, D., Powell, A., King, W., Dambaugh, T. and Raab-Traub, N. 1979. Epstein-Barr Virus: Structure of the viral DNA and analysis of viral RNA in infected cells. Biochim. Biophy. Acta Reviews on Cancer 560:355-373.
24. Powell, A.L.T., King, W. and Kieff, E. 1979. Epstein-Barr Virus Specific RNA. III. Mapping of DNA encoding viral RNA in restringent infection. J. Virol. 29:261-274.
25. Keiff, E., Raab-Traub, N., Given, D., King, W., Powell, A., Pritchett, R. and Dambaugh, T. 1978. "Mapping of Putative Transforming Sequences of EBV DNA." In: Oncogenesis and Herpesviruses III, Part I, F. Rapp and G. de The (Eds.), I.A.R.C., Lyon, pp 527-552.
26. Powell, A.L.T., Gordon, M.P., Caspary, W.J., Greene, J.J. and Ts'o, P.O.P. 1978. Studies on spin labeled ribonucleic acids encapsulated by viral proteins. Nucleic Acid Research 5:3977-3992.
27. Kidson, D., Thomas, A.L. and Cohen, P. 1970. Interactions of hormonal steroids in nucleic acids: III. Role of polymer structure. Biochemistry 9:1571-1576.
Research Interests:
To understand the roles of enzymes and proteins in developing and ripening fruit, I have three major topics of research:
(1) Identify functions in green fruit that can improve resistance of red fruit to pathogens
I study how green fruit are able to resist most fungal pathogens and how these functions can be added to red ripe fruit to reduce rotting. I have studied the structure and function of polygalacturonase inhibitor proteins (PGIPs), small plant cell wall associated glycoproteins that were originally identified as inhibitors of specific PGs from fungal pathogens of plants. PGIPs, expressed abundantly in the absence of fungal contact in immature green fruit but less so in ripe fruit, are leucine rich repeat (LRR) proteins and thus are similar to several pathogen race-specific resistance factors in plants and to proteins in animals involved in protein-protein interactions, extracellular matrix deposition, and cell adhesion. When expressed copiously in transgenic tomato plants, fruit PGIPs can reduce the growth of a fungal pathogen whose PG is inhibited by the PGIP and when the expression of fruit PGIPs is reduced in green fruit, the green fruit become substantially more susceptible to decomposition by the fungus.
(2) Analyze the function of Arabidopsis transcription factors in tomato
Using a population of tomato lines expressing each of the transcription factors (TFs) identified in the Arabidopsis genome generously provided by Mendel Biotechnology Inc. and Seminis Vegetable Seeds, I have catalogued the consequences of their expression by five developmental and tissue specific promoters. I am particularly interested in identifying effects on fruit morphology, ripening, and pathogen susceptibility.
(3) Characterize functions of proteins and enzymes that modify the cell wall during fruit ripening
I determine how proteins, such as expansin, associated with the carbohydrate scaffolding of the cellular integument influence the hydrolytic activity of enzymes, such as polygalacturonase (PG), in the wall, allowing us to understand some of the complex interactions that contribute to the development, ripening and deterioriative processes in fruit. Using transgenic plants with reduced or enhanced expression of expansin, PG or cellulases, I have evaluated the roles of these proteins on fruit softening, paste characteristics, cell wall structures, and susceptibility to fungal pathogens.
My laboratory work is done in the laboratory of Prof. Alan B. Bennett in the Plant Reproductive Biology Building at UC Davis and I have collaborated with Dr. John Labavitch and his research group also in the Plant Reproductive Biology Building.
Prior to coming to UC Davis, I worked for three years in the Friedrich Miescher Institute, Basel, Switzerland with Dr. Fred Meins. Before that I was in the Crown Gall Group at the University of Washington, Seattle, working with the late, Dr. Milton P. Gordon in the Biochemistry Department and with Dr. Eugene Nester in the Microbiology Department. I did my first post-doctoral studies with Dr. Elliott Kieff (ekieff@rics.bwh.harvard.edu), then at the Kovler Center for Viral Oncology at the University of Chicago.
http://www.plantsciences.ucdavis.edu/bennett/lab/index.html
Teaching Interests:
Undergraduate Research Proposal preparation - BIT188.
This course is intended for students actively participating in undergraduate research, or who plan to do so in the near future. This is a writing intensive course that can be considered a laboratory in scientific writing, You will learn how to define a research problem with a faculty mentor, how to design well-controlled experiments, and how to present your ideas to others.
http://www.plantsciences.ucdavis.edu/Classes_2006/BIT_188_2006/index.htm
Courses Taught:
BIT 188 Undergraduate Research Proposal preparation
- Term(s): Spring
BIT 161B Plant genetics and biotechnology
- Term(s): Winter