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

Abstract

SummaryHost-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.

Biotech Potatoes in the 21st Century: 20 Years Since the First Biotech Potato

“…Host induced gene silencing (HIGS) is a relatively new approach for controlling plant pathogens that relies on RNA interference to target the expression of essential pathogen genes. This strategy has been used to target a wide range of pathogen types including insects (reviews by Baum et al 2007;Huvenne and Smagghe 2010), nematodes (reviewed by Huang et al 2006;Yadav et al 2006;Fairbairn et al 2007;Sindhu et al 2009), fungi (Nowara et al 2010;Tinoco et al 2010;Yin et al 2011;Zhang et al 2012;Koch et al 2013;Panwar et al 2013;Pliego et al 2013;Ghag et al 2014), parasitic weeds (Tomilov et al 2008), and oomycetes (Govindarajulu et al 2014;VegaArreguin et al 2014;Jahan et al 2015). Pathogen effectors essential for virulence or Bhousekeeping^genes necessary for normal pathogen growth are typically the targets for HIGS.…”

Genetic Engineering and Sustainable Crop Disease Management: Opportunities for Case-by-Case Decision-Making

“…Recent research clearly highlights the substantial potential which RNA silencing offers for management of diseases caused by biotrophic fungi, necrotrophic fungi, and oomycetes [86][87][88][89][90][91]. These studies report partial to complete control of diseases caused by several of the most important pathogens worldwide.…”

RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/<em>Aspergillus</em> Pathosystem

“…In plants, RNA interference signals can travel cell to cell, with small interfering RNA (siRNA) and high molecular weight RNA being responsible for the systemic posttranscriptional gene silencing 23,24 , even inside fungal pathogens that are in close contact with plant host 25 . The effectiveness of RNAi on plant-mediated silencing of fungal-pathogen genes has been described in few plant pathosystems, for these, visual examination of symptoms in the aerial parts of the plants (leaves) allowed disease quantification, i.e., oomycete Bremia in lettuce 26 , Puccinia in wheat 27 and Fusarium in banana 28 . Much more difficult is to evaluate RNAi effectiveness to control mycotoxins in plants, particularly aflatoxins in peanuts as the leaves show no symptoms of infection, the organs invaded (seeds) are under several inches of soil, the occurrence of infection is unpredictable, and only chemical analysis can determine the presence of aflatoxins.…”