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Research
Interests One of my major interests is the regulation of plant growth and cell expansion. In particular, my laboratory is focused on environmental problems affecting plant growth: soil salinity, drought and cold. There is a very strong linkage between cell elongation, plant productivity and crop yields. The production of all plant parts is dependent upon the supply of external resources, such as water, mineral nutrients or carbon. Cell elongation is important for the capture of these resources, particularly when they are limiting growth. An increase in cell size will increase cell surface area, enabling roots to explore more of the soil for water and minerals, and leaves to capture more photosynthetic radiation. The size of a stressed plant is dependent upon cell production and cell expansion, both of which may be affected by stress. Through the use of new techniques in biotechnology, we can make better plants, which are more suitably adapted to these environmental conditions. Grape production for raisins and wine is one of the largest and most important agricultural commodities in the US. In the year 2000, grapes had a crop value of 3 billion dollars, and was the number one fruit and sixth in overall crop value behind corn, soy, hay, wheat, and cotton. The California wine industry had over 13 billion dollars in retail sales and over a 33 billion dollar impact upon the California economy. Furthermore, it is well established that the consumption of wine at moderate levels has undeniable health benefits including reducing the risk of cardiovascular disease, stroke and cancer. Both phenolics and flavonoids in wines contribute to these health benefits. Grape production efficiency is hampered by abiotic stresses like drought, freezing temperatures, and soil salinization. Drought stress is, by far, the leading cause of agricultural production losses among abiotic and biotic stresses. However, for grape, water-deficit stress can actually be beneficial. Several studies have shown that grapes derived from water-stressed vines have increased levels of phenolics and anthocyanins, resulting in the production of a superior quality wine. However, the molecular and biochemical basis for these characteristics are poorly understood. An integrative and quantitative analysis of mRNA, protein, and metabolite changes following abiotic stress imposition is required to enhance production efficiency under stress conditions and to understand the plant-derived contribution to improved wine characteristics. It will also require the customization and application of comprehensive bioinformatics systems to track and analyze changes that arise in response to abiotic stress and potentially related to aroma, flavor, and color characteristics of grape juice and wine. One long-term goal of our research is to develop comprehensive genomic tools to facilitate the genetic engineering of improved abiotic stress tolerance traits in V. vinifera. The specific objectives for accomplishing this goal include: 1) extensive gene discovery through large-scale expressed sequence tag (EST) sequencing and mRNA expression profiling using cDNA microarray-based expression monitoring in roots, leaves, and fruits of grapevines exposed to multiple abiotic stresses; 2) global mRNA expression profile data will be complemented by protein expression analyses using state-of-the-art proteomics methodologies; and 3) identification of specific metabolites and metabolite profiles in grapevines and fruit following abiotic stress that confer desirable aroma, flavor and color characteristics and improved health benefits. Metabolite profiles from grape juice of well-watered and water-deficit-treated vines will be compared with quantitative data from mRNA and protein expression patterns using comprehensive bioinformatics systems to store and analyze data sets. Ultimately, these data sets will be integrated into a reliable prediction model for wine characteristics. Our research will greatly facilitate future gene discovery and enable improvements to be made in both production efficiency and wine quality under environmentally adverse growing conditions. Search For Dr. Cramer's Publications In PubMed Mailing Address: |
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