Poster: Cell Walls

Abs # 1261: Molecular evolution and expression analysis of the Arabidopsis polygalacturonase gene family

Presenter:	Thoma, Sharon L., sthoma@edgewood.edu
Authors	Thoma, Sharon L. (A)   Kim, Joonyup  (B)   Shiu, Shin-Han  (C)   Turner, Ryan  (A)   Patterson, Sara  (B)
Affiliations:	(A): Edgewood College (B): University of Wisconsin, Department of Horticulture (C): Univeristy of Chicago, Department of Ecology and Evolution

During the process of abscission, there is an increase in the expression of cell wall hydrolytic enzymes, including polygalacturonases (PGs). Phylogenetic analysis was carried out and indicated that plant PGs are classified into two major groups and eight subfamilies. An extended analysis of the 65-member Arabidopsis PG family indicates that Arabidopsis PGs are represented in all but one subfamily of the phylogenetic tree. To investigate the extent of functional divergence among the Arabidopsis PG family members, RT-PCR was used to analyze expression patterns. For each PG family member, expression was investigated in infloresences, siliques, leaves, stems, roots, seedlings, and abscission zones. PGs which are close relatives to each other tended to have overlapping but distinct expression profiles, supporting the hypothesis that functional divergence has occurred in the PG gene family, at least at the level of gene expression. Additionally, several PGs were highly expressed in abscission zones, indicating a possible role for the gene products in the process of cell separation during abscission.