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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #431682

Research Project: Development of Versatile Phytophthora-Resistant Almond and Walnut Rootstocks Using Host-Induced Gene Silencing-UC Davis Component

Location: Crops Pathology and Genetics Research

Project Number: 2032-22000-016-22-A
Project Type: Cooperative Agreement

Start Date: Oct 1, 2016
End Date: Jan 31, 2019

Objective:
1) Select multiple candidate gene fragments for suppression of infection by Phytophthora. 2) Test multiple gene fragments for transient gene silencing activity in plant. 3) Test stable walnut Host-induced gene silencing (HIGS) lines for resistance to Phytophthora. 4) Develop and test a transformation system for stable (HIGS) in peach x almond hybrid rootstocks.

Approach:
1) Conduct proteomic and transcriptomic analysis walnut infected tissues to identify and validate the expression of a set of 48 conserved genes among know Phytophthora species; Identify RNAi targets. 2) Build vectors and test RNAi targets using TRV-VIGS vector by infiltrating tomato/tobacco plants and challenging with Phytophthora to validate the best targets; Test synthetic dsRNA as a spray to protect walnut and almond seedlings from Phytophthora infection. 3) Build binary vectors to express genes to induce HIGS against Phytophthora; Transform walnut somatic embryos of Paradox walnut rootstock select embryos/shoots that are resistant to Phytophthora and validate these in greenhouse. 4) Develop and select somatic embryogenic lines from developing embryos obtained from controlled crosses between peach and almond; Transform the peach-almond hybrid somatic embryos and select embryos/shoots that are resistant to Phytophthora and validate these in the greenhouse.