Author(s): Adam Hales, Laureana Lazarte
Mentor(s): Yu-Ya Liang
Institution UVU
A recently discovered putative DNA virus causes significant damage to Brassica species in Utah. This virus, vectored by Brevicoryne brassicae, the cabbage aphid, induces necrotic lesions and brittle leaves in infected plants. Plant viruses are becoming increasingly problematic as climate change expands the range of vectors, exposing plants to novel pathogens. The objective of this study was to investigate the genetic basis of resistance to this virus. A total of 200 accessions from 10 different Brassica species were used, some of which had been previously reported for virus resistance. These plants were grown in a greenhouse setting using a randomized complete block design (RCBD) with three replicates, and leaf tissue was collected for DNA extraction and sequencing. After 45 days, plants were inoculated with the virus via plant tissue from a symptomatic cabbage aphid colony. After inoculation, disease evaluation was conducted using a newly developed disease severity rating (DSR) system tailored to this virus-host interaction. The DSR used a scale from 1 to 10 to assess the plant’s condition following infection, where a score of '1' indicated complete plant health, and '10' represented complete plant death. The results showed an average DSR of 6.14 for all accessions. B. oleracea accessions had the lowest average DSR of 5.05, while B. juncea accessions had the highest DSR of 7.64. Notably, B. rapa, a host with previously reported virus resistance, had an average DSR of 7.43. The data also indicated that the DSR followed a normal distribution in B. oleracea. Therefore, the phenotypic data and SNP information from B. oleracea will be used in a Genome-Wide Association Study (GWAS) to identify regions associated with responses to this virus. The findings from this study can then be utilized in breeding efforts to safeguard this genus against this dangerous pathogen.