Holaphyllamine, a steroid, is able to induce defense responses in Arabidopsis thaliana and increases resistance against bacterial infection

Abderrakib Zahid (1) , Rim Jaber (1) , Ferdousse Laggoun (1) , Arnaud Lehner (1) , Isabelle Remy-Jouet (2) , Olivier Pamlard (3) , Sandra Beaupierre (4) , Jérôme Leprince (5) , Marie-Laure Follet-Gueye (1) , Maite Vicre-Gibouin (1) , Xavier Latour (6) , Vincent Richard (7) , Catherine Guillou (4) , Patrice P. Lerouge (1) , Azeddine Driouich (1) , Jean-Claude Mollet (1)

1 Glyco-MEV - Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale
2 Pharmacologie des Dysfonctionnements Endotheliaux et Myocardiques
3 DCSO - Laboratoire de synthèse organique
4 ICSN - Institut de Chimie des Substances Naturelles
5 DC2N - Différenciation et communication neuronale et neuroendocrine
6 LMSM - Laboratoire de Microbiologie Signaux et Microenvironnement
7 IRIB - Institute for Research and Innovation in Biomedicine

A chemical screen of plant-derived compounds identified holaphyllamine, a steroid, able to trigger defense responses in Arabidopsis thaliana and improve resistance against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. A chemical screen of 1600 plant-derived compounds was conducted and allowed the identification of a steroid able to activate defense responses in A. thaliana at a concentration of 1 µM without altering growth. The identified compound is holaphyllamine (HPA) whose chemical structure is similar to steroid pregnanes of mammals. Our data show that HPA, which is not constitutively present in A. thaliana, is able to trigger the formation of reactive oxygen species, deposition of callose and expression of several pathogenesis-related genes of the salicylic and jasmonic acid pathways. In addition, the results show that pre-treatment of A. thaliana seedlings with HPA before infection with the pathogenic bacterium Pseudomonas syringae pv tomato DC3000 results in a significant reduction of symptoms (i.e., reduction of bacterial colonies). Using A. thaliana mutants, we have found that the activation of defense responses by HPA does not depend on BRI1/BAK1 receptor kinases. Finally, a structure/function study reveals that the minimal structure required for activity is a 5-pregnen-20-one steroid with an equatorial nucleophilic group in C-3. Together, these findings demonstrate that HPA can activate defense responses that lead to improved resistance against bacterial infection in A. thaliana.

Mots clés: Callose; Chemical screen; Elicitor; Holaphyllamine; PATHOGENESIS-RELATED; Plant defense; Pseudomonas syringae pv tomato DC3000; ROS; Steroid

Domaines: Polymères; Biochimie [q-bio.BM]; Phytopathologie et phytopharmacie; Biologie moléculaire; Génomique, Transcriptomique et Protéomique [q-bio.GN]; Réseaux moléculaires [q-bio.MN]; Organisation et fonctions cellulaires [q-bio.SC]; Interactions cellulaires [q-bio.CB]; Gamétogenèse; Biotechnologies; Amélioration des plantes

Abderrakib Zahid, Rim Jaber, Ferdousse Laggoun, Arnaud Lehner, Isabelle Remy-Jouet, et al.. Holaphyllamine, a steroid, is able to induce defense responses in Arabidopsis thaliana and increases resistance against bacterial infection. Planta, 2017, 246 (6), pp.1109-1124. ⟨10.1007/s00425-017-2755-z⟩. ⟨hal-01837955⟩