Research Accomplishment Reports 2011

Chemical Genetic Dissection of Plant Cellulose Synthesis

S. DeBolt
Department of Horticulture

 

Non-Technical Summary

Plant cell walls are composed of highly glycosylated proteins and polysaccharides, including pectin, hemicelluloses and cellulose, which form a complex and dynamic structure that modulates cell expansion. The primary cell wall polysaccharide is cellulose, and it stands as the most abundant biopolymer in the world. Cellulose has long been utilized by the forage, pulp, paper and textile industries, and has been targeted as a vehicle for renewable energy and carbon sequestration.

In addition cellulose and cell wall structure are vital to fruit softening and ripening processes in horticulture crops worldwide. Despite the agricultural and industrial importance, cellulose biosynthesis in plants is still poorly understood.

The overarching goal of this research is to develop small molecule probes that inhibit specific aspects of the cellulose biosynthetic process, which can then be used to dissect underlying molecular processes.

2011 Project Description

Ph.D.- COMPLETED: Darby Harris (University of Kentucky, Lexington) Molecular and chemical dissection of plant cellulose synthesis (Graduated 9th, Dec 2011)(accepted a post doctoral position at Cornell University); Matthew Simson (University of Kentucky, Lexington) Defining and correlating grape quality attributes in Kentucky Aug 2008 to 2011 (Kentucky wine industry); Arun Sampathkumar (Max Planck Institute of Molecular Plant Physiology, Germany)- External Advisor graduated in 2011 (post doc at Cambridge University).

CANDIDATES Jan 1st-2008 to present- Meera Nair (University of Kentucky, Lexington) The molecular role of phyosteryl glycosides in plants Aug 2008 - present; Chad Brabham (August 2011- present), Pharmacogenomics in plants- examination of cell wall biogenesis in model grasses; Mizuki Tetano (August 2011- present) Cell wall structure and modulation in Seteria viridis.

POST DOCTORAL ASSOCIATE ADVISING Venugopal Mendu Dec 2009- present Carloalberto Petti Feb 2010 - Xia (Summer) Ye - May 2010 - present; Yumei Zheng (2011- present).

DISSEMINATION Horticultural Research Farm Annual Tour- Website dissemination: http://www.uky.edu/Ag/Horticulture/DeBolt%20Lab/Site/Welcome.html

2011 Impact

This research project is aimed at understanding and modulating the most abundant biopolymer on the planet, cellulose. This plant derived biopolymer is central to food, clothing, medicine, shelter, energy and livestock feed, there are very few times in the average humans life not spent in direct contact with cellulose or one of its deconstruction products. It is surprising that we still no so little about how it is made by the plant and how it can be modified to improve the range of products derived from it. Hence, resolving the structure of cellulose remains one of the most important research questions in agriculture and more broadly, research science.

Our current research has resulted in one patent, and a series of broadly disseminated publications showing that via chemical genetics we can make mutant cellulose synthases that create cellulose more amenable to degradation by hydrolytic enzymes. Several additional discoveries have been made in how cellulose is synthesized in plants.

2011 Publications

Mendu V, Stork J, Harris D, Debolt S. (2011) Cellulose synthesis in two secondary cell wall processes in a single cell type. Plant Signal Behav. 1;6(11).

Mendu V, Harman-Ware AE, Crocker M, Jae J, Stork J, Morton S 3rd, Placido A, Huber G, Debolt S. (2011) Identification and thermochemical analysis of high-lignin feedstocks for biofuel and biochemical production. Biotechnol Biofuels. Oct 21;4:43.

Mendu V, Griffiths JS, Persson S, Stork J, Downie AB, Voiniciuc C, Haughn GW, DeBolt S. (2011) Subfunctionalization of cellulose synthases in seed coat epidermal cells mediates secondary radial wall synthesis and mucilage attachment Plant Physiol. Sep;157(1):441-53.

Joshi CP, Thammannagowda S, Fujino T, Gou JQ, Avci U, Haigler CH, McDonnell LM, Mansfield SD, Mengesha B, Carpita NC, Harris D, Debolt S, Peter GF. (2011) Perturbation of wood cellulose synthesis causes pleiotropic effects in transgenic aspen. Mol Plant. 2011 Mar;4(2):331-45.

Nair M, Debolt S. Analysing cellulose biosynthesis with confocal microscopy Methods Mol Biol. 2011;715:141-52.

Sampathkumar A, Lindeboom JJ, Debolt S, Gutierrez R, Ehrhardt DW, Ketelaar T, Persson S. (2011) Live cell imaging reveals structural associations between the actin and microtubule cytoskeleton in arabidopsis. Plant Cell. 2011 Jun;23(6):2302-13.