Allegheny College, B.S.
Cornell University, Ph.D.
Highly damaging reactive oxygen species (ROS) are generated by a wide variety of factors in plants. High light can result in photo-oxidative damage when ROS generated during photosynthesis exceed that of the antioxidant capacity. Such conditions occur when high light is combined with drought, temperature extremes, or nutrient deprivation. Other abiotic factors in the plant’s environment also lead to increased ROS including UV-B, air pollutants, certain herbicides, and phytotoxic metals. I have a general interest in understanding how plants protect themselves against ROS.
The current research focus of my laboratory is on vitamin C (ascorbic acid), a crucial antioxidant and cellular reductant in both plants and animals and an essential component of the human diet. Despite the importance of this small molecule in plant physiology and animal health, only very recently has significant progress been made towards understanding how plants synthesize ascorbic acid. To identify genes involved in this biosynthetic pathway we have isolated Arabidopsis thaliana mutants that are deficient in ascorbic acid. One of these mutants was isolated by virtue of its sensitivity to ozone and has led to the isolation of a gene that encodes a key ascorbic acid biosynthetic enzyme. We are currently cloning additional genes involved in the synthesis of ascorbic acid. Our research on plant antioxidants has potential downstream applications in the areas of plant environmental stress tolerance and human health.
In addition, a new initiative on plant folic acid biosynthesis has begun in my laboratory in collaboration with colleagues at the Boyce Thompson Institute at Cornell University.
Those interested in learning more about Arabidopsis thaliana (the model plant for many plant molecular genetic studies) can check out The Arabidopsis Information Resource (TAIR).
Conklin, P.L., S.A. Saracco, S.R. Norris and R.L. Last (2000) Identification of vitamin C-
deficient Arabidopsis thaliana mutants. Genetics, 154: 847-856.
Conklin, P.L., S.R. Norris, G.L. Wheeler, E.H. Williams, N. Smirnoff and R.L. Last (1999) Genetic evidence for the role of GDP-mannose in plant ascorbic acid (vitamin C) biosynthesis. Proc Natl Acad Sci USA 96: 4198-4203.
Conklin, P.L. (1998) Vitamin C: a new pathway for an old antioxidant. Trends Plant Sci 3: 329-330.
Conklin, P.L., J.E. Pallanca, R.L. Last and N. Smirnoff. (1997) L-ascorbic acid metabolism in the ascorbate deficient Arabidopsis mutant. Plant Physiol 115: 1277-1285.
Conklin, P.L., E.W. Williams and R.L. Last. (1996) Environmental stress sensitivity of an ascorbic acid-deficient Arabidopsis mutant. Proc Natl Acad Sci USA 93: 9970-9974.
Conklin, P.L. and R.L. Last (1995) Differential accumulation of antioxidant enzyme mRNAs
in Arabidopsis thaliana exposed to ozone. Plant Physiol 109: 203-212.