Location: Cereal Crops ResearchTitle: Validation of the P. teres f. teres effectors VR1 and VR2 conferring virulence on Rika barley identified in the bi-parental mapping population 15A × 6A
|WYATT, NATHAN - North Dakota State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/13/2019
Publication Date: 2/17/2020
Citation: Friesen, T.L., Wyatt, N.A. 2020. Validation of the P. teres f. teres effectors VR1 and VR2 conferring virulence on Rika barley identified in the bi-parental mapping population 15A × 6A. 15th European Conference on Fungal Genetics. Poster No.289.
Interpretive Summary: .
Technical Abstract: Net form net blotch is an economically important foliar disease of barley (Hordeum vulgare) caused by the fungal pathogen Pyrenophora teres f. teres. Yield losses have been reported in the range of 10-40% and complete yield loss has been observed under environmental conditions highly favorable to the pathogen. Little is known as to the molecular mechanisms involved in the host-pathogen interaction. To investigate the mechanisms of P. teres f. teres virulence, a mapping population was developed from a cross between two California P. teres f. teres isolates 15A and 6A that showed a differential response on Rika barley, with 6A being virulent and 15A avirulent on Rika. Two virulence QTL conferred by 6A, VR1 and VR2, were identified. Within the 15A × 6A population, progeny isolate #72 contained VR2 but not VR1 and no isolates were identified containing VR1 but not VR2. Using the full genome sequences of isolates 15A and 6A, candidate genes were identified for VR1 and VR2. In progeny isolate #72 a CRISPR-Cas9-ribonucleoprotein (CRISPR-Cas9-RNP) mediated gene disruption was performed in the VR2 candidate gene, resulting in a loss of virulence on Rika barley and providing strong preliminary confirmation that the candidate gene was VR2. VR2 encodes a secreted protein with a mature amino acid sequence length of 405 amino acids and contains no predicted protein domains and no homology to any known proteins. The VR2 gene is currently being functionally characterized using heterologous expression in Pichia pastoris and gain-of-function transformation into parental isolate 15A. A gain-of-function transformation of VR1 into isolate 15A resulted in isolate 15A becoming virulent on Rika barley and providing strong preliminary confirmation for the candidate being VR1. VR1 encodes a secreted protein with a mature amino acid length of 557 amino acids with no predicted protein domains or homology to any known proteins. VR1 is currently being functionally characterized in the same manner as VR2. Additional characterization is being performed using CRISPR-Cas9-RNP mediated co-editing in isolate 6A to both perform a double gene disruption of VR1 and VR2 as well as in vitro pull-down assays using VR1 and VR2 as bait proteins for barley cellular lysates. The characterizations of VR1 and VR2 will contribute significant knowledge to the molecular interaction between barley and P. teres f. teres during a susceptible interaction.