Plant-pathogenic bacteria are the causative agents of diseases in important agricultural crops and ornamental plants.
The severe economic burden of these diseases requires seeking new approaches for their control, particularly because
phytopathogenic bacteria are often resistant to available treatments. The type II secretion (T2S) system is a key virulence factor used by major groups of phytopathogenic bacteria. The T2S machinery transports many hydrolytic enzymes responsible for degradation of the plant cell wall, thus enabling successful colonization and dissemination of the bacteria in the plant host. The genetic inactivation of the T2S system leads to loss of virulence, which strongly suggests that targeting the T2S could enable new treatments against plant-pathogenic bacteria. Accordingly, we have designed and optimized an assay to identify small-molecule inhibitors of the T2S system. This assay uses a double parametric output: measurement of bacterial growth and the enzymatic activity of cellulase, which is secreted via the T2S pathway in our model organism Dickeya dadantii. The assay was evaluated by screening natural extracts, culture filtrates isolated from rhizosphere bacteria, and a collection of pharmaceutically active compounds in LOPAC^1280. The calculated Z′ values of 0.63, 0.63, and 0.58, respectively, strongly suggest that the assay is applicable for a high-throughput screening platform.

Authors: 
Tran, N. et al.
Short Description: 
Report on the development and application of a quantitative assay amenable for high-throughput screening (HTS) of natural product libraries and small-molecule inhibitors to identify compounds that interfere with the T2S process.
Product Number: 
ORESU-R-13-010
Entry Date: 
Friday, May 9, 2014
Length: 
10 pp.
Size and Format: 
8 1/2 x 11, online
Source (Journal Article): 
Journal of Biomolecular Screening
DOI Number (Journal Article): 
10.1177/1087057113485426
Year of Publication: 
2013