High-Copy Transposons from a Pathogen Give Rise to a Conserved sRNA Family with a Novel Host Immunity Target

Abstract

Small RNAs (sRNAs) are involved in gene silencing in multiple ways, including through cross-kingdom transfers from parasites to their hosts. Little is known about the evolutionary mechanisms enabling eukaryotic microbes to evolve functional mimics of host small regulatory RNAs. Here, we describe the identification and functional characterization of SINE_sRNA1, an sRNA family derived from highly abundant short interspersed nuclear element (SINE) retrotransposons in the genome of the wheat powdery mildew pathogen. SINE_sRNA1 is encoded by a sequence motif that is conserved in multiple SINE families and corresponds to a functional plant microRNA (miRNA) mimic targeting Tae_AP1, a wheat gene encoding an aspartic protease only found in monocots. Tae_AP1 has a novel function enhancing both pattern-triggered immunity (PTI) and effector-triggered immunity (ETI), thereby contributing to the cross activation of plant defenses. We conclude that SINE_sRNA1 and Tae_AP1 are functional innovations, suggesting the contribution of transposons to the evolutionary arms race between a parasite and its host.

Keywords

aspartic protease; Blumeria; cross-kingdom RNAi; transposable elements; wheat

Published in

Molecular plant-microbe interactions
2024, volume: 37, number: 4

SLU Authors

• Bourras, Salim

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    
  • University of Zürich

Associated SLU-program

SLU Plant Protection Network

UKÄ Subject classification

Evolutionary Biology
Plant Biotechnology

Publication identifier

• DOI: https://doi.org/10.1094/MPMI-10-23-0176-SC

Permanent link to this page (URI)

https://res.slu.se/id/publ/140781