Applications of Plant Biotechnology
Applications of Plant Biotechnology
About this eBook
optimal moisture content for popping since my father had a moisture meter at the grain elevator. I also grew many trees and bushes that I am still doing today on our 11 acres of land which has two ponds. I also still grow my own popcorn that I eat almost daily. After high school I attended the University of Illinois at Urbana-Champaign and received a B.S. in Agricultural Science in 1961. I was offered an assistantship at the California Institute of Technology in Pasadena, California and worked with James Bonner on DNA and RNA isolation and characterization and purified E. coli RNA polymerase for the whole lab to use. I received my Ph.D. in Biochemistry in 1965. During graduate school Jacob and Monod in France were making great discoveries in the area of microbial genetics, enzymology and biochemistry and Phil Filner was a fellow graduate student working with tobacco suspension cultures. It seemed that such cultures would be ideal for doing mutant selection and biochemistry with plants like Jacob and Monod were doing with bacteria. After one year of postdoctoral work with Bonner, mostly working on his histone-RNA concept, I went to work with a company, International Minerals and Chemical in Libertyville, Illinois. Interestingly they became interested in the idea of plant genetic engineering long before it was possible. After two years 1968 I was offered an Assistant Professor position in the Agronomy Department at the University of Illinois and I am still here. The first project carried out with Bill Ogren was to attempt to select plant mutants that lacked photorespiration since this process found in C3 plants decreases net photosynthesis greatly. My idea was to grow soybean plants under low CO2 conditions where plants with photorespiration would lose CO2 and any mutants would not, so they would survive. When the C4 plant corn, that does not photorespire, was placed in a sealed chamber with soybeans the CO2 level was pulled down and the soybeans died in a week. Unfortunately no mutants were found after screening about 350,000 mutagenized seedlings and later studies by others with larger numbers of the much smaller Arabidopsis plants were also unsuccessful. No one has been able to alter photorespiration yet.
I also began selection with carrot and tobacco suspension cultures for resistance to toxic amino acid analogs and was successful with tryptophan Trp , methionine, proline, lysine and phenylalanine analogs. A number of studies were carried out with these lines that provided new information about the control of amino acid biosynthesis in plants. Since in most cases the resistance lines had increased levels of the target free amino acid the idea of selecting mutants with improved nutritional quality or higher secondary compounds related to the amino acid was proposed. Of all the mutants selected the ones that were resistant to Trp analogs have been studied the most with the first publication in 1972, and we are still doing work with the gene from tobacco that encodes a feedback resistant form of the Trp biosynthesis control enzyme, anthranilate synthase ASA2 . Much of the enzyme and amino acid analysis work was done by Jeff Brotherton who worked in this lab for many years. We have done selection for resistance or testing for resistance of different cultures with herbicides, fungal toxins, salt, iron-deficiency chlorosis, heavy metals and allyl alcohol. The mechanism of action of a number of herbicides including glyphosate Roundup has also been studied by students of Fred Slife in my lab. The selection with glyphosate has revealed that resistance in cultures of many different species is due to amplification of the target gene. It seemed important to know if various treatments affect tissue culture cell viability so I did a study to find viability stains and found phenosafranin to be excluded from live cells and