Nature Communications (Sep 2023)

NET4 and RabG3 link actin to the tonoplast and facilitate cytoskeletal remodelling during stomatal immunity

  • Timothy J. Hawkins,
  • Michaela Kopischke,
  • Patrick J. Duckney,
  • Katarzyna Rybak,
  • David A. Mentlak,
  • Johan T. M. Kroon,
  • Mai Thu Bui,
  • A. Christine Richardson,
  • Mary Casey,
  • Agnieszka Alexander,
  • Geert De Jaeger,
  • Monika Kalde,
  • Ian Moore,
  • Yasin Dagdas,
  • Patrick J. Hussey,
  • Silke Robatzek

DOI
https://doi.org/10.1038/s41467-023-41337-z
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 19

Abstract

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Abstract Members of the NETWORKED (NET) family are involved in actin-membrane interactions. Here we show that two members of the NET family, NET4A and NET4B, are essential for normal guard cell actin reorganization, which is a process critical for stomatal closure in plant immunity. NET4 proteins interact with F-actin and with members of the Rab7 GTPase RABG3 family through two distinct domains, allowing for simultaneous localization to actin filaments and the tonoplast. NET4 proteins interact with GTP-bound, active RABG3 members, suggesting their function being downstream effectors. We also show that RABG3b is critical for stomatal closure induced by microbial patterns. Taken together, we conclude that the actin cytoskeletal remodelling during stomatal closure involves a molecular link between actin filaments and the tonoplast, which is mediated by the NET4-RABG3b interaction. We propose that stomatal closure to microbial patterns involves the coordinated action of immune-triggered osmotic changes and actin cytoskeletal remodelling likely driving compact vacuolar morphologies.