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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #438452

Research Project: Development of RNA Interference-based Resistance in Almond and Walnut Rootstocks Against Phytophthora Pathogens

Location: Crops Pathology and Genetics Research

Project Number: 2032-22000-017-012-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 20, 2020
End Date: Sep 19, 2025

1) Facilitate rootstock improvement via RNA interference (RNAi)-based host-induced gene silencing (HIGS) for resistance to Phytophthora. 2) Evaluate HIGS resistance in transformed walnut rootstocks and optimize somatice embryogenesis (SE) and genetic transformation protocols for almond rootstocks.

1) For the walnut rootstock improvement, 80 HIGS-transgenic lines of embryos have already been developed. We will culture HIGS-transformant lines in media containing plant hormones to induce shoot development. Then we will conduct testing of transformants for resistance to Phytophthora. Transgenic lines showing strong inhibition of in planta pathogen growth will be propogated and regenerated to whole plants in pots and further test will be conducted in the greenhouse. 2) For almond rootstock improvement, we will multiply somatic embryos of almond x peach hybrids to obtain sufficient material and carry out genetic transformation. Transformed hybrid embryo lines will be propagated and shoots will be induced as walnut embryos. Then we will conduct the inoculation of Phytophthora pathogens and evaluate resistance.