Abstract Detail

Genomics / Proteomics

Tuominen, Lindsey K. [1], Wang, Hong-Qiang [1], Tsai, Chung-Jui [1].

Network Analysis Reveals Possible Links Between BAHD Acyltransferase Evolution and Phenylpropanoid Metabolism in Populus.

Trees often employ chemical defenses to cope with a wide range of biotic and abiotic stresses that might otherwise prevent these long-lived species from surviving and successfully reproducing year after year. Populus is an interesting model genus for research on chemical defenses in trees, as these species accumulate both high levels and a wide diversity of non-structural phenylpropanoid compounds. However, the basis for this metabolic complexity is not well understood. Members of the BAHD acyltransferase superfamily have been shown to contribute to chemical modification of the phenylpropanoid compounds in other plant species, so we hypothesized that this gene family might play a role in phenylpropanoid diversity in Populus. We have found that BAHD acyltransferases in Populus are highly diverse relative to other genomes analyzed, with over ninety Populus genes clustering into six of seven clades for the BAHD superfamily as a whole. Interestingly, we found evidence for previously undescribed conserved motifs in the superfamily as well as clade-specific conserved motifs, which may help account for differential functions between clades. A phylogeny of characterized proteins and putative proteins from five plant genomes also revealed a tendency for BAHD genes to cluster by taxon; three such subgroups were found for Populus. Within each subgroup, some genes exhibited different expression patterns across tissues, genotypes, and stresses, suggesting diversification of their functions in planta. Network analyses of genes in the expanded subgroups revealed that their expression patterns were highly correlated with those of phenylpropanoid pathway genes across experiments. This evidence seems to support a link between the BAHD superfamily and the diversification of chemical defenses in Populus. Work currently in progress is aiming to elucidate the biochemical and physiological roles of a subset of four closely-related BAHD genes in Populus to determine the directionality of this link.

Broader Impacts:
Understanding the basis for metabolic diversity in long-lived species can help contribute towards efforts to develop more effective methods for integrated pest management, understand growth-defense tradeoffs, and identify likely targets for metabolic engineering.

1 - University of Georgia, Warnell School of Forestry & Natural Resources, 180 E Green Street, Athens, GA, 30602-2152, USA

Keywords:
Functional genomics
secondary metabolism
metabolic complexity
gene duplication
gene family evolution
Populus.

Presentation Type: Oral Paper:Papers for Topics
Session: 53
Location: 551B/Convention Center
Date: Wednesday, August 4th, 2010
Time: 10:15 AM
Number: 53001
Abstract ID:96