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United States Department of Agriculture

Agricultural Research Service

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Research Project: EFFECTORS OF PATHOGENICITY IN THE STAGONOSPORA NODORUM-WHEAT PATHOSYSTEM, CHARACTERIZATION OF HOW S. NODORUM INDUCES DISEASE

Location: Cereal Crops Research

Project Number: 5442-22000-048-09
Project Type: General Cooperative Agreement

Start Date: Feb 01, 2010
End Date: Jan 31, 2014

Objective:
Objective 1. Evaluate the importance of HST-host gene interactions identified using culture filtrates and purified toxins in conjunction with wheat mapping populations including the development of differential wheat lines for each toxin. Objective 2. Identify candidate HSTs by mass spec analysis of purified active protein preparations and by using a bioinformatics gene selection approach. Objective 3. Verify candidate genes using heterologous expression, transformation, and site directed gene disruption. Objective 4. Characterize the function and mode of action of SnTox3 to identify the molecular and biochemical mechanism whereby the toxin is effective in inducing disease.

Approach:
We have established that the Stagonospora nodorum-wheat interaction consists of pathogen produced effector proteins i.e. host selective toxins (HSTs) that interact with dominant host gene products to induce disease. This interaction is similar to a classical gene-for-gene interaction except that host recognition of the effector proteins leads to susceptibility rather than resistance and therefore acts in an inverse gene-for-gene manner. We have published or submitted for publication five of these HST – host gene interactions. Additionally, we have accumulated evidence for four more interactions. Each of these nine interactions involves a single proteinaceous HST that interacts directly or indirectly with a dominant host gene product leading to disease. In this proposal we would like to 1) characterize the newly identified interactions, 2) clone the associated HST encoding genes from the pathogen for further analysis of individual interactions, and 3) do functional analysis and evaluate the mode of action of SnTox3, a recently cloned HST involved in the SnTox3-Snn3 interaction.

Last Modified: 8/2/2014
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