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

摘要

Summary 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.