Monday, April 19, 2010
LL Conference Facility (Hilton Clearwater Beach)
The functions of many NAC proteins relate to different aspects of lignocellulosic biomass production in model species such as Arabidopsis and rice. However, translating the knowledge from model species to poplar and switchgrass, the two most studied bioenergy crops in the Bioenergy Science Center (BESC), has been a challenge. With the emerging genome data from poplar and switchgrass, and application of advanced bioinformatic analysis methods, a systematic prediction of NAC transcription factors for improving biomass yield and quality in relation to lignocellulosic bioenergy production was made. A total of 1,232 NAC protein sequences from 11 different organisms were analyzed by sequence phylogeny based on protein DNA-binding domains. Eight whole genomes (Arabidopsis, rice, poplar, grape, sorghum, soybean, moss (Physcomitrella patens), and spike moss (Selaginella moellendorffii)) and three not yet fully sequenced genomes (maize, switchgrass, and Medicago truncatula) were included. Ninety-two potential switchgrass PvNAC genes and 148 poplar PtNAC genes were identified. The 1,232 NAC proteins were phylogenetically classified into eight subfamilies, each of which was further divided into subgroups according to their tree topology. The subgroups were then grouped into different clades each sharing conserved motif patterns in the C-terminal sequences, and those that may function in plant cell wall development were further identified through gene expression pattern analysis using publicly available microarray data. This study provides a bioinformatic baseline for further functional analyses of candidate NAC genes for improving cell wall and environmental tolerance traits in the bioenergy crops switchgrass and poplar.