Dr.
Asaph Cousins
.jpg) 509-335-7218
acousins@wsu.edu
Assistant Professor, School of Biological Sciences. Ph.D. 2001,
Arizona State University.
Research
The ability to monitor and predict how plants both influence and are influenced by future climatic conditions is critical for the health of our planet and for future food production. My research couples molecular biology techniques with plant physiology and mathematical modeling of photosynthesis to understand the mechanistic processes dictating plant-environment interactions. This research uses a variety of experimental techniques, including field experiments, leaf and whole plant gas exchange, recombinant DNA techniques, biochemistry, and metabolite analysis to elucidate how the interactions of plant light utilization, carbon and nutrient assimilation, and isotope discrimination are influenced by changing environmental conditions.
The two main areas my research is focusing on are:
1) Plant energy metabolism
Understanding the flow of energy between metabolic pathways and organelles is important for determining how plants will respond to environmental stress and future climatic conditions. This research uses gas exchange, mass spectrometry and metabolite analysis to understand the key steps in photosynthesis, photorespiration and nitrogen metabolism that coordinate the energy flow between these competing processes.
2) Carbon and oxygen isotope exchange in plants
Isotope analysis of atmospheric CO2 is an important tool for monitoring ecosystem changes in plant metabolism in response to climate change. However, to interpret the atmospheric CO2 isotopic signature requires an understanding of the fractionation steps associated with specific processes during leaf gas exchange. This research uses molecular tools coupled with stable isotope analysis and mathematical modeling of photosynthesis and isotope exchange to understand how leaf metabolism and anatomy influence the exchange of carbon and water between plants and their environment.
I am excited to discuss student research opportunities and will be accepting graduate students in the Spring of 2008. Please contact me at acousins@wsu.edu if you are interested in joining the lab.
Selected
Publications
Cousins A.B., Baroli I., Badger M.R., Ivakov A., Lea P.J., Leegood R.C., von Caemmerer S. (2007) The role of PEPc during photosynthetic isotope exchange and stomatal conductance. Plant Physiology In press
Griffiths H., Cousins A.B., Badger M.R., and von Caemmerer S (2007) Discrimination in the dark: resolving the interplay between metabolic and physical constraints to PEPC activity during the CAM cycle. Plant Physiology 143, 1055-1067
Cousins A.B., Badger M.R., von Caemmerer S. (2006) A transgenic approach to understanding the influence of carbonic anhydrase on C18OO discrimination during C4 photosynthesis. Plant Physiology 142, 662-672
Cousins A.B., Badger M., von Caemmerer S. (2006) Carbonic anhydrase and its influence on carbon isotope discrimination during C4 photosynthesis: Insights from antisense RNA in Flaveria bidentis. Plant Physiology 141, 232-242
Cousins A.B. and Bloom A.J. (2004) Oxygen consumption during leaf nitrate assimilation in a C3 and C4 plant: the role of mitochondrial respiration. Plant Cell and Environment. 27, 1537-1545.
Rachmilevitch S., Cousins A.B. and Bloom A.J. (2004) Nitrate assimilation in plant shoots depends on photorespiration. Proceedings of the National Academy of Sciences.101, 11506-11510
Cousins A.B. (2004). Man bests machine, this time. The Scientist. 18: 58.
Cousins A.B. and Bloom A.J. (2003) Influence of elevated CO2 and nitrogen nutrition on photosynthesis and nitrate photoassimilation in maize (Zea mays L.). Plant Cell and Environment 26, 1525-1530.
Cousins A.B., Adam N.R., Wall G.W., Kimball B.A., Pinter Jr. P.J., Ottman M.J., Webber A.N. (2003) Development of C4 photosynthesis in Sorghum leaves grown under free-air CO2 enrichment (FACE) Journal of Experimental Botany 54, 1969-1975.
Cousins A.B., Adam N.R., Wall G.W., Kimball B.A., Ottman M.J., Webber A.N. (2002) Photosystem II energy use, non-photochemical quenching and the xanthophyll cycle in Sorghum bicolor grown under drought and Free-Air CO2 Enrichment (FACE) conditions. Plant Cell and Environment 25, 1551-1559
Cousins A.B., Adam N. R., Wall G.W., Kimball B.A., Pinter Jr. P.J., Leavitt S.W., LaMorte R.L., Matthias A.D., Ottman M.J., Thompson T.L., Webber A.N. (2001) Reduced photorespiration and increased energy-use efficiency in young CO2-enriched sorghum leaves. New Phytologist 150, 275-284.
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