Phylogenetic and Structural Relationships of the PR5 Gene Family Reveal an Ancient Multigene Family Conserved in Plants and Select Animal Taxa
- 437 Downloads
Pathogenesis-related group 5 (PR5) plant proteins include thaumatin, osmotin, and related proteins, many of which have antimicrobial activity. The recent discovery of PR5-like (PR5-L) sequences in nematodes and insects raises questions about their evolutionary relationships. Using complete plant genome data and discovery of multiple insect PR5-L sequences, phylogenetic comparisons among plants and animals were performed. All PR5/PR5-L protein sequences were mined from genome data of a member of each of two main angiosperm groups—the eudicots (Arabidoposis thaliana) and the monocots (Oryza sativa)—and from the Caenorhabditis nematode (C. elegans and C. briggsase). Insect PR5-L sequences were mined from EST databases and GenBank submissions from four insect orders: Coleoptera (Diaprepes abbreviatus and Biphyllus lunatus), Orthoptera (Schistocerca gregaria), Hymenoptera (Lysiphlebus testaceipes), and Hemiptera (Toxoptera citricida). Parsimony and Bayesian phylogenetic analyses showed that the PR5 family is paraphyletic in plants, likely arising from 10 genes in a common ancestor to monocots and eudicots. After evolutionary divergence of monocots and eudicots, PR5 genes increased asymmetrically among the 10 clades. Insects and nematodes contain multiple sequences (seven PR5-Ls in nematodes and at least three in some insects) all related to the same plant clade, with nematode and insect sequences separating as two clades. Protein structural homology modeling showed strong similarity among animal and plant PR5/PR5-Ls, with divergence only in surface-exposed loops. Sequence and structural conservation among PR5/PR5-Ls suggests an important and conserved role throughout the evolutionary divergence of the diverse organisms from which they reside.
KeywordsThaumatin Osmotin Pathogenesis-related protein group 5 (PR5) Insect Nematode Plant Phylogeny
The authors would like to acknowledge Dr. Phat Dang, Bryan Backlaski, and Kimberly Poole for their technical assistance.
- Hong Q, Gutierrez-Aguirre I, Barlic A, Malovrh P, Kristan K, Podlesek Z, Macek P, Turk D, Gonzalez-Manas JM, Lakey JH, Anderluh G (2002) Two-step membrane binding by Equinatoxin II, a pore-forming toxin from the sea anemone, involves an exposed aromatic cluster and a flexible helix. J Biol Chem 277:41916–41924PubMedCrossRefGoogle Scholar
- Ibeas JI, Yun DJ, Damsz B, Narasimhan ML, Uesono Y, Ribas JC, Lee H, Hasegawa PM, Bressan RA, Pardo JM (2001) Resistance to the plant PR-5 protein osmotin in the model fungus Saccharomyces cerevisiae is mediated by the regulatory effects of SSD1 on cell wall composition. Plant J 25:271–280PubMedCrossRefGoogle Scholar
- Larget B, Simon D (1999) Markov chain Mente Carlo algorithms for the baysian analysis of phylogenetic trees. Mol Biol Evol 16:111–120Google Scholar
- Lesk AM (2003) Introduction to protein architecture. Oxford University Press, New YorkGoogle Scholar
- Roberts W, Selitrennikoff CP (1990) Zeamatin, an antifungal protein from maize with membrane-permeabilizing activity. J Gen Microbiol 136:1771–1778Google Scholar
- Swofford DL (2003) PAUP*: Phylogenetic analysis using parsiomony (*and other methods). Sinauer Associates, Sunderland, MAGoogle Scholar
- Zitzer A, Harris JR, Kemminer SE, Zitzer O, Bhakdi S, Muething J, Palmer M (2000) Vibrio cholerae cytolysin: assembly and membrane insertion of the oligomeric pore are tightly linked and are not detectably restricted by membrane fluidity. Biochim Biophys Acta 1509:264–274PubMedCrossRefGoogle Scholar