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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #436654

Research Project: Putting Phenotypic and Genotypic Tools to Work for Improving Walnut Rootstocks

Location: Crops Pathology and Genetics Research

Project Number: 2032-22000-017-003-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: May 1, 2019
End Date: Jun 30, 2023

1. Analyze sRNA profile of a transgenic interstock that is being evaluated for resistance to Cheery leafroll virus (CLRV) without a hypersensitive reaction which can lead to blackline disease (BLD). 2. Challenge interspecific hybrids of Juglans (J.) microcarpa x J. regia for tolerance to CLRV which will not develop BLD. 3. Analyze genomes of selected CLRV variants in American black walnut species, J. hindsii, J. major, J. microcarpa and J. nigra, and map the pathogenicity determinants that overcame resistance in the black walnuts.

Cooperator works with the ARS researcher in recruiting a post-doctoral fellow to conduct the studies. Small RNA sequencing will be done on transgenic walnut lines to determine the pool of sRNAs derived from Cherry leafroll virus (CLRV) in the transgenic walnut lines. Establish grafts and evaluate resistance to CLRV in the transgenic walnut lines and as also in the selections from the backcross populations. Culture and purify CLRV and develop an inoculation method to test for hypersenisitivity in walnuts. Use qRT-PCR and/or ELISA for the estimation of virus titer in test plants.