Asaph Cousins

Biography

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Education

PhD, Plant Biology, Arizona State University

Research Interests

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 CO2isotopic 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.

Please contact me at acousins@wsu.edu if you are interested in discussing our research.

Representative Publications:

• Cousins A.B., Mullendore D.L. & Sonawane B.V. (2020) Recent developments in mesophyll conductance in C3, C4, and crassulacean acid metabolism plants. Plant J, 101, 816-830.
• Ellsworth P.Z., Feldman M.J., Baxter I. & Cousins A.B. (2020) A genetic link between leaf carbon isotope composition and whole-plant water use efficiency in the C4 grass Setaria. Plant J, 102, 1234-1248.
• Sonawane B.V. & Cousins A.B. (2020) Mesophyll CO2 conductance and leakiness are not responsive to short- and long-term soil water limitations in the C4 plant Sorghum bicolor. Plant J, 103, 1590-1602.
• Ermakova M., Arrivault S., Giuliani R., Danila F., Alonso-Cantabrana H., Vlad D., Ishihara H., Feil R., Guenther M., Borghi G.L., Covshoff S., Ludwig M., Cousins A.B., Langdale J.A., Kelly S., Lunn J.E., Stitt M., von Caemmerer S. & Furbank R.T. (2020) Installation of C4 photosynthetic pathway enzymes in rice using a single construct. Plant Biotechnol J.
• Serrano-Romero E.A. & Cousins A.B. (2020) >Cold acclimation of mesophyll conductance, bundle-sheath conductance and leakiness in Miscanthus x giganteus. New Phytol, 226, 1594-1606.
• Pathare V.S., Koteyeva N. & Cousins A.B. (2020) Increased adaxial stomatal density is associated with greater mesophyll surface area exposed to intercellular air spaces and mesophyll conductance in diverse C4 grasses. New Phytol, 225, 169-182.
• Pathare V.S., Sonawane B.V., Koteyeva N. & Cousins A.B. (2020) C4 grasses adapted to low precipitation habitats show traits related to greater mesophyll conductance and lower leaf hydraulic conductance. Plant Cell Environ, 43, 1897-1910.
• Sonawane B.V. & Cousins A.B. (2019) Uncertainties and limitations of using carbon-13 and oxygen-18 leaf isotope exchange to estimate the temperature response of mesophyll CO2 conductance in C3 plants. New Phytol, 222, 122-131.
• Cano F.J., Sharwood R.E., Cousins A.B. & Ghannoum O. (2019) The role of leaf width and conductances to CO2 in determining water use efficiency in C4 grasses. New Phytol, 223, 1280-1295.
• DiMario R.J. & Cousins A.B. (2019) A single serine to alanine substitution decreases bicarbonate affinity of phosphoenolpyruvate carboxylase in C4 Flaveria trinervia. J Exp Bot, 70, 995-1004.
• Kolbe A.R., Studer A.J., Cornejo O.E. & Cousins A.B. (2019) Insights from transcriptome profiling on the non-photosynthetic and stomatal signaling response of maize carbonic anhydrase mutants to low CO2. BMC Genomics, 20, 138.
• Boyd R.A., Cavanagh A.P., Kubien D.S. & Cousins A.B. (2019) Temperature response of Rubisco kinetics in Arabidopsis thaliana: thermal breakpoints and implications for reaction mechanisms. J Exp Bot, 70, 231-242.
• Ubierna N., Cernusak L.A., Holloway-Phillips M., Busch F.A., Cousins A.B. & Farquhar G.D. (2019) Critical review: incorporating the arrangement of mitochondria and chloroplasts into models of photosynthesis and carbon isotope discrimination. Photosynth Res, 141, 5-31.
• Giuliani R., Karki S., Covshoff S., Lin H.C., Coe R.A., Koteyeva N.K., Quick W.P., Von Caemmerer S., Furbank R.T., Hibberd J.M., Edwards G.E. & Cousins A.B. (2019a) Knockdown of glycine decarboxylase complex alters photorespiratory carbon isotope fractionation in Oryza sativa leaves. J Exp Bot, 70, 2773-2786.
• Giuliani R., Karki S., Covshoff S., Lin H.C., Coe R.A., Koteyeva N.K., Evans M.A., Quick W.P., von Caemmerer S., Furbank R.T., Hibberd J.M., Edwards G.E. & Cousins A.B. (2019b) Transgenic maize phosphoenolpyruvate carboxylase alters leaf-atmosphere CO2 and (13)CO2 exchanges in Oryza sativa. Photosynth Res, 142, 153-167.