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Quantitative Interactor Screening with next-generation Sequencing (QIS-Seq) identifies Arabidopsis thaliana MLO2 as a target of the Pseudomonas syringae type III effector HopZ2

Jennifer D Lewis13, Janet Wan1, Rachel Ford1, Yunchen Gong2, Pauline Fung2, Hardeep Nahal2, Pauline W Wang12, Darrell Desveaux12* and David S Guttman12*

Author Affiliations

1 Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada

2 Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, M5S 3B2, Canada

3 Plant Gene Expression Center, USDA, 800 Buchanan St., Albany, CA, 94710, USA

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BMC Genomics 2012, 13:8  doi:10.1186/1471-2164-13-8

Published: 9 January 2012



Identification of protein-protein interactions is a fundamental aspect of understanding protein function. A commonly used method for identifying protein interactions is the yeast two-hybrid system.


Here we describe the application of next-generation sequencing to yeast two-hybrid interaction screens and develop Quantitative Interactor Screen Sequencing (QIS-Seq). QIS-Seq provides a quantitative measurement of enrichment for each interactor relative to its frequency in the library as well as its general stickiness (non-specific binding). The QIS-Seq approach is scalable and can be used with any yeast two-hybrid screen and with any next-generation sequencing platform. The quantitative nature of QIS-Seq data make it amenable to statistical evaluation, and importantly, facilitates the standardization of experimental design, data collection, and data analysis. We applied QIS-Seq to identify the Arabidopsis thaliana MLO2 protein as a target of the Pseudomonas syringae type III secreted effector protein HopZ2. We validate the interaction between HopZ2 and MLO2 in planta and show that the interaction is required for HopZ2-associated virulence.


We demonstrate that QIS-Seq is a high-throughput quantitative interactor screen and validate MLO2 as an interactor and novel virulence target of the P. syringae type III secreted effector HopZ2.

Next-generation sequencing; yeast two-hybrid; high-throughput screening; Arabidopsis; Pseudomonas syringae; type III effector; MLO2; HopZ