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The Brookhaven Plant Imaging Program uses non-invasive imaging of molecules tagged with short-lived radioisotopes including carbon-11 (half-life: 20.4 m), nitrogen-13 (half-life: 10 m) and fluorine-18 (half-life 110 m) to contribute directly to the DOE-OBER need for, “Fundamental research on microbes and plants to understand the genetic and biochemical mechanisms that control growth, development, and metabolism, provid(ing) knowledge needed … to develop new bioenergy crops and improved biofuel production processes that are cost effective and sustainable.” Our overarching goal is to investigate how key plant hormones like auxin regulate allocation and metabolism of carbon and nitrogen resources making plants hardier (i.e., stress resistant) and productive in marginal soils.

Our recent efforts are largely focused on growth and tissue development within grasses, the ideal bioenergy candidates. C4 Grasses in particular are fast growing, and tend to require less water and nutrients. While part of this effort makes use of direct bioenergy candidates such as sweet sorghum and switchgrass, we also utilize model grass systems such as maize, rice, Brachypodium, and Setaria because of the availability of diverse genetic resources. By combining imaging and functional genomics technologies to study transgenic and mutant lines in such grass models, we can explore relationships between genes and phenotypes that were previously inaccessible and ultimately translate new knowledge to more relevant bioenergy grasses.

Why study the whole plant? Many questions in plant biology can be studied using destructive techniques at tissue or cellular levels. However, a whole plant must integrate, by nutrient sensing and hormonal signaling, the various functions of different organs (e.g. leaves, stems, and roots). Furthermore, a plant must coordinate source-sink relations and the distribution of different resources supplied by leaves and roots throughout the whole plant. In order to understand the coordination of plant growth with the movement of resources and signaling molecules, we need to study the whole plant using non-invasive approaches that allow testing of basic functions of the plant (i.e., biochemical and physiological) without disturbing its natural biological status.

Hormonal Signaling

In plants, hormonal signaling contributes substantially to growth and development, and to the regulation of physiological and biochemical traits relevant to bioenergy, including tissue architecture and stress resistance. Hormones, such as auxin, play major roles in all aspects of the development of form (morphology), physiology, and biochemistry. By understanding the mechanisms underlying plant signaling from hormone homeostasis to changes in gene expression, plant function and growth, we can potentially manipulate complex suites of traits, such as those conferring stress resistance.

Source-Sink Relations

Source-sink relations also contribute substantially to the determination of traits relevant to bioenergy. Resources captured in one set of tissues must be delivered to the different developing tissues (e.g., photosynthate to developing leaves, stems, roots) for growth. Given their distinct functions, source and sink tissues must be coordinated (e.g., photosynthesis and soil nutrient uptake), which is done via numerous signals including the resources themselves (e.g., sugar signaling), as well as by specific signal molecules or hormones that are transported from one tissue to another. For example, sinks (growing tissues or storage organs) provide feedback to source leaves that determines whether photosynthesis in source leaves will run at or below maximum capacity. Our long-term goals include determining the fundamental mechanisms driving transport, and the mechanisms underlying source-sink coordination that help determine root and stem growth and architecture, and the interactions of regulatory mechanisms under stress conditions.

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Last Modified: February 14, 2013
Please forward all questions about this site to: Kathy Folkers