Plant Physiol. Tips for Better Browsing
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on November 16, 2007; 10.1104/pp.107.106229

OPEN ACCESS ARTICLE
This Article
Free via Open Access: OA
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrowOA All Versions of this Article:
146/3/888    most recent
pp.107.106229v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Major, I. T.
Right arrow Articles by Constabel, C. P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Major, I. T.
Right arrow Articles by Constabel, C. P.
Agricola
Right arrow Articles by Major, I. T.
Right arrow Articles by Constabel, C. P.

Received August 3, 2007
Accepted November 6, 2007

Functional Analysis of the Kunitz Trypsin Inhibitor Family in Poplar Reveals Biochemical Diversity and Multiplicity in Defense against Herbivores

Ian T. Major and C. Peter Constabel *

Centre for Forest Biology and Department of Biology, University of Victoria, Stn CSC, PO Box 3020, Victoria, BC, V8W 3N5, Canada

* Corresponding author; email: cpc{at}uvic.ca.

We investigated the functional and biochemical variability of Kunitz trypsin inhibitor (KTI) genes of hybrid poplar (Populus trichocarpa x P. deltoides). Phylogenetic analysis, expressed sequence tag databases, and western blot analysis confirmed that these genes belong to a large and diverse gene family with complex expression patterns. Five wound- and herbivore-induced genes representing the diversity of the KTI gene family were selected for functional analysis, and shown to produce active KTI proteins in E. coli. These recombinant KTI proteins were all biochemically distinct and showed clear differences in efficacy against trypsin, chymotrypsin, and elastase type proteases, suggesting functional specialization of different members of this gene family. The in vitro stability of the KTIs in the presence of reducing agents and elevated temperature also varied widely, emphasizing the biochemical differences of these proteins. Significantly, the properties of the recombinant KTI proteins was not predictable from primary amino acid sequence data. Proteases in midgut extracts of Malacosoma disstria, a lepidopteran pest of Populus, were strongly inhibited by at least two of the KTI gene products. This study suggest that the large diversity in the poplar KTI family is important for biochemical and functional specialization, which may be important in the maintenance of pest resistance in long-lived plants such as poplar.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2007 by the American Society of Plant Biologists