2017 ASHS Annual Conference
Characterization of Dominant Resistance to Tobacco Etch Virus Discovered in Capsicum baccatum and Its Introgression into a Capsicum annuum Background
Characterization of Dominant Resistance to Tobacco Etch Virus Discovered in Capsicum baccatum and Its Introgression into a Capsicum annuum Background
Thursday, September 21, 2017: 9:15 AM
Kohala 3 (Hilton Waikoloa Village)
Tobacco etch virus (TEV) is an agriculturally important pathogen of peppers (Capsicum spp.) and several other species including perennial weeds that can act as virus reservoirs. Most commercial pepper varieties lack resistance to TEV. A novel dominant gene conferring resistance to TEV has been isolated from a wild accession Capsicum baccatum, after screening more than 500 Capsicum accessions. Successful introgression of this gene into a Capsicum annuum breeding line has been achieved after multiple interspecific crossing cycles. Extensive screening has confirmed the presence of a single, dominant gene for resistance to TEV. Repeated inoculation of selfed progeny from the donor parent initially showed TEV symptoms, however, all symptoms subsided and plant vigor was restored in more than 95% of inoculated plants. The pattern of symptom development following inoculation suggests involvement of a hypersensitive response-like mechanism as the mode of TEV resistance conferred by this gene.
A preliminary screening of resistance gene donor parents (n = 20) donor parents, three known susceptible checks, three selections of the initial introgression that were selfed until stable, and several backcrosses with the original introgression (n = 22) has revealed an interesting pattern of segregation for TEV symptomology. Plants of the original introgression lines showed an average segregation pattern of 3:1, resistant to susceptible, supporting the single dominant gene model. The second part of this experiment was expanded to include five commercial checks with known modes of resistance to specific strains of TEV, as well as 10 each of six different selections of the original recurrent parent with the introgression; to confirm 100 percent susceptibility. Available results support the evidence that there is only one original source of the resistance in our introgression, and that the gene action is single, dominant. Future work will include selection of three resistant lines that contain the original introgression and a known susceptible recurrent parent and increasing seed to screen 200 of each family for additional segregation studies in response to TEV. The final goal is to utilize genotyping-by-sequencing of a select F2 family to discover SNPs linked to the dominant TEV resistance locus.
A preliminary screening of resistance gene donor parents (n = 20) donor parents, three known susceptible checks, three selections of the initial introgression that were selfed until stable, and several backcrosses with the original introgression (n = 22) has revealed an interesting pattern of segregation for TEV symptomology. Plants of the original introgression lines showed an average segregation pattern of 3:1, resistant to susceptible, supporting the single dominant gene model. The second part of this experiment was expanded to include five commercial checks with known modes of resistance to specific strains of TEV, as well as 10 each of six different selections of the original recurrent parent with the introgression; to confirm 100 percent susceptibility. Available results support the evidence that there is only one original source of the resistance in our introgression, and that the gene action is single, dominant. Future work will include selection of three resistant lines that contain the original introgression and a known susceptible recurrent parent and increasing seed to screen 200 of each family for additional segregation studies in response to TEV. The final goal is to utilize genotyping-by-sequencing of a select F2 family to discover SNPs linked to the dominant TEV resistance locus.