The pectin methylesterase gene complement of Phytophthora sojae: Structural and functional analyses, and the evolutionary relationships with its oomycete homologs

Ospina-Giraldo, Manuel D.; Horowitz, B. B.

The pectin methylesterase gene complement of Phytophthora sojae: Structural and functional analyses, and the evolutionary relationships with its oomycete homologs

Abstract

Phytophthora sojae is an oomycete pathogen that causes the disease known as root and stem rot in soybean plants, frequently leading to massive economic damage. Additionally, P. sojae is increasingly being utilized as a model for phytopathogenic oomycete research. Despite the economic and scientific importance of P. sojae, the mechanism by which it penetrates the host roots is not yet fully understood. It has been found that oomycetes are not capable of penetrating the cell wall solely through mechanical force, suggesting that alternative factors facilitate breakdown of the host cell wall. Pectin methylesterases have been suggested to be important for Phytophthora pathogenicity, but no data exist on their role in the P. sojae infection process. We have scanned the newly revised version of the annotated P. sojae genome for the presence of putative pectin methylesterases genes and conducted a sequence analysis of all gene models found. We also searched for potential regulatory motifs in the promoter region of the proposed P. sojae models, and investigated the gene expression levels throughout the early course of infection on soybean plants. We found that P. sojae contains a large repertoire of pectin methylesterase-coding genes and that most of these genes display similar motifs in the promoter region, indicating the possibility of a shared regulatory mechanism. Phylogenetic analyses confirmed the evolutionary relatedness of the pectin methylesterase-coding genes within and across Phytophthora spp. In addition, the gene duplication events that led to the emergence of this gene family appear to have occurred prior to many speciation events in the genus Phytophthora. Our results also indicate that the highest levels of expression occurred in the first 24 hours post inoculation, with expression falling after this time. Our study provides evidence that pectin methylesterases may be important for the early action of the P. sojae infection process.

Title	The pectin methylesterase gene complement of Phytophthora sojae: Structural and functional analyses, and the evolutionary relationships with its oomycete homologs
Creator	Ospina-Giraldo, Manuel D.
Creator	Horowitz, B. B.
Publisher	PLoS ONE
Academic Department	Biology
Division	Natural Sciences
Organization	Lafayette College
Date Issued	November 6, 2015
Date Available	2015-12-04T14:55:04Z
Type	Article
Language	English
Bibliographic Citation	Horowitz, B. B. and M. D. Ospina-Giraldo. (2015 Nov 6) "The pectin methylesterase gene complement of Phytophthora sojae: Structural and functional analyses, and the evolutionary relationships with its oomycete homologs." PLoS ONE 10 (11): e0142096.
Standard Identifier	Handle 10385/2054
Standard Identifier	DOI 10.1371/journal.pone.0142096
Permalink	http://hdl.handle.net/10385/2054
Rights Statement	Creative Commons - Attribution
Rights Holders	Ospina-Giraldo, Manuel D.
Rights Holders	Horowitz, B. B.