Silencing a Simple Extracellular Leucine-Rich Repeat Gene OsI-BAK1 Enhances the Resistance of Rice to Brown Planthopper Nilaparvata lugens

Int J Mol Sci. 2021 Nov 10;22(22):12182. doi: 10.3390/ijms222212182.

Abstract

Many plant proteins with extracellular leucine-rich repeat (eLRR) domains play an important role in plant immunity. However, the role of one class of eLRR plant proteins-the simple eLRR proteins-in plant defenses against herbivores remains largely unknown. Here, we found that a simple eLRR protein OsI-BAK1 in rice localizes to the plasma membrane. Its expression was induced by mechanical wounding, the infestation of gravid females of brown planthopper (BPH) Nilaparvata lugens or white-backed planthopper Sogatella furcifera and treatment with methyl jasmonate or abscisic acid. Silencing OsI-BAK1 (ir-ibak1) in rice enhanced the BPH-induced transcript levels of three defense-related WRKY genes (OsWRKY24, OsWRKY53 and OsWRKY70) but decreased the induced levels of ethylene. Bioassays revealed that the hatching rate was significantly lower in BPH eggs laid on ir-ibak1 plants than wild-type (WT) plants; moreover, gravid BPH females preferred to oviposit on WT plants over ir-ibak1 plants. The exogenous application of ethephon on ir-ibak1 plants eliminated the BPH oviposition preference between WT and ir-ibak1 plants but had no effect on the hatching rate of BPH eggs. These findings suggest that OsI-BAK1 acts as a negative modulator of defense responses in rice to BPH and that BPH might exploit this modulator for its own benefit.

Keywords: Nilaparvata lugens; OsI-BAK1; ethylene; plant defense responses; rice; simple extracellular leucine-rich repeat protein.

MeSH terms

  • Abscisic Acid / pharmacology
  • Acetates / pharmacology
  • Animals
  • Cyclopentanes / pharmacology
  • Ethylenes / metabolism
  • Female
  • Gene Expression Regulation, Plant / drug effects
  • Gene Silencing
  • Hemiptera / physiology*
  • Leucine / chemistry*
  • Organophosphorus Compounds / pharmacology
  • Oryza / genetics*
  • Oviposition / drug effects
  • Oxylipins / pharmacology
  • Plant Defense Against Herbivory / genetics*
  • Plant Immunity / genetics
  • Plant Proteins / genetics*
  • Plant Proteins / isolation & purification
  • Plant Proteins / metabolism
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • Transcription Factors / metabolism

Substances

  • Acetates
  • Cyclopentanes
  • Ethylenes
  • Organophosphorus Compounds
  • Oxylipins
  • Plant Proteins
  • Transcription Factors
  • Abscisic Acid
  • methyl jasmonate
  • ethylene
  • Leucine
  • ethephon