Host-induced gene silencing inhibits the biotrophic pathogen causing downy mildew of lettuce

Manjula Govindarajulu, Lynn Epstein, Tadeusz Wroblewski, Richard W Michelmore

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


Host-induced gene silencing (HIGS) is an RNA interference-based approach in which small interfering RNAs (siRNAs) are produced in the host plant and subsequently move into the pathogen to silence pathogen genes. As a proof-of-concept, we generated stable transgenic lettuce plants expressing siRNAs targeting potentially vital genes of Bremia lactucae, a biotrophic oomycete that causes downy mildew, the most important disease of lettuce worldwide. Transgenic plants, expressing inverted repeats of fragments of either the Highly Abundant Message #34 (HAM34) or Cellulose Synthase (CES1) genes of B. lactucae, specifically suppressed expression of these genes, resulting in greatly reduced growth and inhibition of sporulation of B. lactucae. This demonstrates that HIGS can provide effective control of B. lactucae in lettuce; such control does not rely on ephemeral resistance conferred by major resistance genes and therefore offers new opportunities for durable control of diverse diseases in numerous crops.

Original languageEnglish (US)
Pages (from-to)875-883
Number of pages9
JournalPlant Biotechnology Journal
Issue number7
StatePublished - Sep 1 2015


  • Bremia lactucae
  • HIGS
  • Lactuca sativa
  • Disease resistance
  • Gene silencing
  • RNA interference

ASJC Scopus subject areas

  • Plant Science
  • Biotechnology
  • Agronomy and Crop Science


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