Thursday, November 16, 2006 - 10:00 AM

Novel cell wall mutants of maize with enhanced bio-processing characteristics.

Wilfred Vermerris1, Reuben Tayengwa1, Karen Koch2, Don McCarty2, Mark Davis3, Steven Thomas3, Maureen McCann4, and Nicholas Carpita5. (1) University of Florida, UF Genetics Institute & Agronomy Dept., P. O. Box 103610, Gainesville, FL 32610-3610, (2) University of Florida Horticultural Sciences department, Fifield Hall, Gainesville, FL 32611, (3) National Renewable Energy Laboratory, National Bioenergy Center, 1617 Cole Blvd, Golden, CO 80401, (4) Purdue University, Department of Biological Sciences, 915 W. State Street, West Lafayette, IN 47907, (5) Purdue University Department of Botany and Plant Pathology, 915 W. State Street, West Lafayette, IN 47907

The composition of the plant cell wall affects agronomic traits such as lodging susceptibility and pest and disease resistance, as well as forage quality.  The processing efficiency of ligno-cellulosic biomass also largely depends on cell wall composition.  With the increasing demand for petroleum-based fuels in Southeast Asia, a desire in the US to become less dependent on imported oil, and a need to curb the emission of greenhouse gases, the production of fuels and chemical feedstocks from ligno-cellulosic biomass will require large-scale bio-processing of corn stover and other sources of vegetative biomass.  The bio-processing efficiency can be enhanced by producing plants that are more amenable to physico-chemical pretreatment and enzymatic hydrolysis.

 In order to identify cell-wall related genes with a potential impact on agronomic traits and post-harvest processing, we have screened the maize UniformMu population using near infrared reflectance (NIR) spectroscopy as part of an NSF-funded Plant Genome project that is nearing completion. (  The UniformMu population consists of families in a common genetic background (inbred line W22) with a high forward mutation rate as a result of active Mutator transposons.  We developed a screening protocol and evaluated 1,500 F2 families (30,000 plants).  This resulted in 40 novel mutants with altered NIR spectra but no apparent visual phenotypes.  In addition, we identified 29 mutants with distinct visual phenotypes.  

 These mutants are now being characterized in more detail using pyrolysis-molecular beam mass spectrometry, wet chemical analyses, and lab-scale enzymatic saccharification assays to determine the yield of fermentable sugars from the stover.  In addition, the genes underlying the mutations are being cloned using a PCR-based method.  An overview of the project and several specific examples will be presented.  These combined efforts will allow the development of new lines for specific agro-industrial applications.  The mutants will be available to the scientific community.