Just a light touch can transmit PepMV from plant to plant, making the disease very contagious in a greenhouse once the virus has been introduced.
"When I started my research on PepMV, I looked first at the genetic makeup of the European strains," Ling says.
But two PepMV strains in the United States show a distinct divergence from the European varieties.
PepMV strains, he observed a strong similarity to the South American strains.
In contrast, South American and European PepMV strains did not exhibit
Ling also observed that tomato plants developed milder symptoms after infection with Chilean strains of PepMV than after exposure to the European strains.
In his first round of tests, Ling grew out 109 accessions of 5 different Solanum species, which he then inoculated with PepMV. Plants that developed no symptoms and showed little to no detectable levels of PepMV virus accumulation were saved for their seeds and for additional resistance tests.
habrochaites varieties that showed a range of genetic resistance to PepMV. He used the most robust of the three to generate new offspring, which remained symptom-free after exposure to a virus derived from Chilean PepMV strains.