• HRT/CSS 853: Plant Mineral Nutrition and Membrane Transport
• HRT/CSS 852:  Seminar - A genetic approach to understanding abiotic stress tolerance

Education:

Ph.D., Botany/Biochemistry, Iowa State University, Ames, Iowa 1972

M.S., Botany, Miami University, Oxford, Ohio 1967

B.A., Botany, Miami University, Oxford, Ohio, 1964

Physiology of carbohydrate metabolism

We have long been involved in elucidating the metabolic pathways for both biosynthesis and degradation of several acyclic sugar alcohols, e.g., sorbitol and mannitol, and determining the characteristics and tissue, cell, and subcellular locations of those enzymes involved in these pathways. Enzyme identification and characterization currently includes study of regulatory mechanisms at both the protein and gene level. We have, for example, cloned and sequenced the gene for mannose 6-phosphate reductase, a key step in mannitol biosynthesis, and are now investigating those factors involved in its regulation.  Similar work is focused on sugar alcohol transporters.

Stress physiology

We are very interested in developing an understanding of the mechanisms by which plants tolerate abiotic stress, environmental extremes such as salinity, drought, and temperature, especially since several of these mechanisms may be related to the capacity of some plants to synthesize compatible solutes like the acyclic sugar alcohols. Accordingly, we have been looking at how certain abiotic stresses regulate sugar alcohol metabolism, storage, and transport, and how these compounds may accumulate in response to exposure to stress.

Carbohydrate partitioning and photosynthesis

In collaboration with colleagues we have been involved in a variety of projects related to determining patterns of carbohydrate allocation as a result of sink/source interactions. These interactions profoundly affect crop quality and yield, yet little is known about the mechanisms involved.

• C. M. Sickler, G. E. Edwards, O. Kiirats, Z. Gao, W. Loescher. 2007. Response of mannitol-producing Arabidopsis thaliana to abiotic stress.  Functional Plant Biology 34: 382-391.
• S.-H Yang, L.-J. Wang, S.-H. Li, W. Duan, W. H. Loescher, and Z. Liang. 2007. The effects of UV-B radiation on photosynthesis in relation to Photosystem II photochemistry, thermal dissipation and antioxidant defenses in winter wheat (Triticum aestivum L.) seedlings at different growth temperatures.  Functional Plant Biology   34: 907-917.
• Loescher, W, T. Johnson, R. Beaudry, S. Jayanty. 2005. Sorbitol transport, sorbitol, and watercore in apple cultivars differ in watercore susceptibility.  HortScience 40:993-994 (abstract). 
• Gao, Z., S. Jayanty, R. Beaudry, and W. Loescher. 2005. Watercore and sorbitol transporters in apple sink tissues: implications for fruit sugar accumulation and watercore development.  J Amer Soc Hort Sci  130:2:261-268.
• Xu, Y., E. Hanson, J. Flore, W. Loescher. 2004. Boron fertilization and sour cherry (Prunus cerasus) fruit quality.  HortScience 39:796 (abstract).
• U.S. Patent No. 6, 416,985.  Issued July 9, 2002.  Title:  DNA Encoding Mannose 6-Phosphate Reductase and Recombinants Produced Therefrom.  Inventors:  W.H. Loescher, J. Everard, and R. Grumet.
• Gao, Z., L. Maurousset, R. Lemoine, S.-D. Yoo, S. van Nocker, and W. Loescher. 2003. Cloning, expression, and characterization of sorbitol transporters from developing sour cherry (Prunus cerasus) fruit and leaf sink tissues. Plant Physiol 131:1566-1575.
• Loescher, W.H. 2003. Cherries. Encyclopedia of Food Sciences and Nutrition, 2nd Ed. Academic Press, London. pp. 1135-1140.
• Gao, Z., and W.H. Loescher. 2003. Expression of a celery mannose 6-phosphate reductase in Arabidopsis thaliana enhances salt tolerance and induces biosynthesis of both mannitol and a mannitol dimer. Plant Cell and Environment 26: 275-283
• S.-D. Yoo, Gao, Z., C. Cantini, W. Loescher, and S. van Nocker. 2003. Fruit ripening in sour cherry (Prunus cerasus): changes in expression of genes expressing expansins and other cell-wall-modifying enzymes. J Amer Soc Hort Sci 128: 16-22.
• Gao, Z. and W.H. Loescher. 2000. NADPH supply and mannitol biosynthesis: characterization, cloning, and regulation of the nonreversible glyceraldehyde-3-phosphate dehydrogenase in celery leaves. Plant Physiology 124: 321-330.
• Loescher, W.H. and J.D. Everard. 2000. Regulation of sugar alcohol biosynthesis. In: R.C. Leegood, T. D. Sharkey, and S. von Caemmerer, eds., Photosynthesis: physiology and metabolism. Kluwer Academic Pubs., Dordrecht, The Netherlands. pp. 275-299
• Everard, J.D., C. Cantini, R. Grumet, J. Plummer, and W.H. Loescher. 1997. Molecular cloning of mannose 6-phosphate reductase and its developmental expression in celery. Plant Physiology 113:1427-1435.
• Loescher, W.H., and J.D. Everard. 1996. Metabolism of carbohydrates in sinks and sources: sugar alcohols. In: E. Zamski and A. Schaffer, eds., Distribution of photoassimilates in plants and crops: source-sink relationships. Marcel Dekker, Inc.. New York. pp. 185-207.
• Loescher, W.H., J.D. Everard, C. Cantini, and R. Grumet. 1995. Sugar alcohol metabolism in source leaves. In: M. Madore and W. Lucas, eds. Carbon Partitioning and Source-Sink Interactions in Plants, American Society of Plant Physiologists, Rockville, MD. pp. 170-179.
• Everard, J.D., R. Gucci, S.C. Kann, J.A. Flore, and W.H. Loescher. 1994. Gas exchange and carbon partitioning in the leaves of celery (Apium graveolens L.) at various levels of root zone salinity. Plant Physiol. 106:281-292.
• Everard, J.D., V.R. Franceschi, and W.H. Loescher. 1993. Mannose-6-phosphate reductase, a key enzyme in photoassimilate partitioning, is abundant and located in the cytosol of photosynthetically active cells of celery (Apium graveolens L.) source leaves. Plant Physiol. 102:345-356.