Epidermal CCA1 and PMR5 contribute to nonhost resistance in Arabidopsis

Biosci Biotechnol Biochem. 2022 Nov 23;86(12):1623-1630. doi: 10.1093/bbb/zbac160.


Nonhost resistance (NHR) is the most robust and durable resistance in plants, but its spatiotemporal regulation is poorly understood. The circadian clock functions in a tissue-specific manner and regulates individual physiological processes in plants. Using mutant and RNA-seq analyses, we revealed a role of CIRCADIAN CLOCK ASSOCIATED1 (CCA1) in tissue-specific and time-of-day-specific regulation of NHR to Pyricularia oryzae (syn. Magnaporthe oryzae) in Arabidopsis thaliana (Arabidopsis). Targeted perturbation of CCA1 function in epidermis compromised time-of-day-specific regulation of NHR to P. oryzae in Arabidopsis. RNA-seq analysis showed that P. oryzae inoculation alters the transcriptome in penetration 2 (pen2) plants and identified POWDERY MILDEW RESISTANCE 5 (PMR5) as a candidate gene of direct targets of CCA1. Time-of-day-specific penetration resistance to P. oryzae was reduced in Arabidopsis pen2 pmr5 mutant plants. These findings suggest that epidermal CCA1 and PMR5 contribute to the establishment of time-of-day-specific NHR to P. oryzae in Arabidopsis.

Keywords: Arabidopsis thaliana; Pyricularia oryzae; CCA1; PMR5; nonhost resistance.

MeSH terms

  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / metabolism
  • Circadian Clocks* / genetics
  • Circadian Rhythm
  • Epidermis / metabolism
  • Gene Expression Regulation, Plant
  • Mutation
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • Arabidopsis Proteins
  • CCA1 protein, Arabidopsis
  • Transcription Factors
  • PMR5 protein, Arabidopsis

Supplementary concepts

  • Pyricularia oryzae

Grant support