Latest insights into plant defense mechanisms – paper in Science Advances

Molecular Biotechnology /

A recent multidisciplinary study led by Dr. Alexandra Furch (University of Jena) in collaboration with apl. Prof. Gundula Noll and Prof. Dirk Prüfer (Fraunhofer IME, Münster), along with further experts, explores how plants convert pathogen perception into electrical signals, triggering local and systemic defense responses. Surprisingly, the evidence indicates that sieve element occlusion proteins, previously thought to be mainly involved in phloem sealing, also contribute to the signal transmission process.

The team investigated Arabidopsis thaliana and Vicia faba, revealing that the density of the pathogen receptor (FLS2) is notably high in the epidermis and vascular parenchyma, while being low in the mesophyll and absent in sieve elements (SEs). Additionally, the findings highlighted dual cytosolic Ca2+ peaks shortly after recognition of the conserved microbial molecule (flg22), which correlated with voltage shifts from the epidermis to SEs. These electrical signals then manifest as rapid long-range action potentials (APs) or slower short-range variation potentials (VPs). The abundant Ca2+ influx linked to VPs caused transient sieve element occlusion (SEO) near the flg22 perception site, a phenomenon absent in the knockout mutants. The double knockout mutants (Atseor1/2) exhibited increased susceptibility to bacterial attacks from Pseudomonas syringae in comparison to wild-type plants, highlighting the importance of the SEO in plant defense mechanisms.

 

Furch ACU, Zimmermann MR, Noll GA, Wrobel LS, Scholz SS, Buxa-Kleeberg SV, Hafke JB, Fliegmann J, Mithöfer A, Ehlers K, Haufschild T, Nötzold J, Koch AM, Grabe V, Teutemacher F, Maaß J-P, Prüfer D, Oelmüller R, Peiter E, Kogel K-H, van Bel AJE (2025)
Transformation of flg22 perception into electrical signals decoded in vasculature leads to sieve tube blockage and pathogen resistance
Science Advances DOI