Chitinolytic enzymes from Streptomyces albidoflavus expressed in tomato plants: effects on Trichoplusia ni

Tomato ( Lycopersicon esculentum ) cultivars were transformed with genes that encode bacterial chitinolytic enzymes (i.e., endochitinase and chitobiosidase) from Streptomyces albidoflavus . Transgenic tomato plants producing these enzymes were found to have enhanced resistance to cabbage looper, Trichoplusia ni (HÜbner) (Lepidoptera: Noctuidae), consistently reducing the growth rates of larvae. Mortality was significantly increased in two of three feeding trials. Ingestion of endochitinase and chitobiosidase not only affected development of larval T. ni from neonate to ultimate instar, but they also caused mortality and decreased insect weight when exposure began during the third instar. The results of this study provide some insight into the mode of action of the chitinolytic enzymes, by supporting the hypothesis that ingested chitinolytic enzymes damage the chitin component of the peritrophic envelope, leading to increased permeability. The size of marker molecules (FITC-dextrans) that permeated the peritrophic envelopes of T. ni feeding on transgenic plants were 50% larger than those permeating the peritrophic envelopes of T. ni feeding on the control plants. Further research is needed to more clearly identify the sites and modes of action of these chitinolytic enzymes, and the potential for synergy between these enzymes and pathogens, allelochemicals, and other environmental factors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72193/1/j.1570-7458.2001.00817.x.pd

Development of a Geographic Information System for Habitat Suitability Analysis of Protected Species

The Center for Conservation Biology (CCB) at the University of California, Riverside, in association with the California Department of Fish & Game and the U.S. Fish and Wildlife Service, is developing a species monitoring protocol and habitat suitability analysis for “species of concern” located in western Riverside County and the Coachella Valley. The study is central to the multi-species habitat conservation plans (MSHCPs) for these two regions. The CCB has two issues that need to be addressed to simplify and streamline their workflow associated with the MSHCP project. The first is the re-organization of their datasets into a uniform format and the transfer of those data from Microsoft Excel to Microsoft Access to enable the development of a relational database that can be used to enhance access, visualization, analysis, and provide a tool for decision making. The second is a simplification of the procedure used to prepare data for habitat suitability analyses. This report describes (1) the development of a geodatabase that was designed for this project, and (2) the evaluation of the potential to replace the current cumbersome technique being used to develop habitat suitability models with a customized application that can simplify the multivariate analysis of habitat suitability. Extensive evaluation of the current data tables and a users’ needs analysis provided the necessary input for the design of a geodatabase that would enable easy input, access, update, analysis, and visualization of the entire data library being developed for the MSHCPs. A free, downloadable extension, available from Jenness Enterprises, was tested for its potential to meet the needs of the CCB to develop habitat suitability models for selected species of concern (http://www.jennessent.com/arcview/mahalanobis.htm accessed 3/22/04). Comparison of the results from the Jenness extension with the results from the original method suggests that the Jenness extension may be a viable replacement for the original technique