Modified N-acyl-homoserine lactones as chemical probes for the elucidation of plant–microbe interactions

Abstract

Gram-negative bacteria often use N-acyl-homoserine lactones (AHLs) as signal molecules to monitor their local population densities and to regulate gene-expression in a process called "Quorum Sensing" (QS). This cell-to-cell communication allows bacteria to adapt to environmental changes and to behave as multicellular communities. QS plays a key role in both bacterial virulence towards the host and symbiotic interactions with other organisms. Plants also perceive AHLs and respond to them with changes in gene expression or modifications in development. Herein, we report the synthesis of new AHL-derivatives for the investigation and identification of AHL-interacting proteins. We show that our new compounds are still recognised by different bacteria and that a novel biotin-tagged-AHL derivative interacts with a bacterial AHL receptor.

Interactions of Salmonella with animals and plants

“…The contribution of signaling via quorum sensing circuits mediated by either N -acyl homoserine lactones (AHL) or the autoinducer-2 (AI-2) to the behavior of Salmonella in plant-associated bacterial communities and in animal intestines has already been demonstrated ( Ahmer and Gunn, 2011 ; Brandl et al, 2013 ). However, the importance of AHL and AI-2-based signaling in Salmonella during the interactions of Salmonella both with plant and animal bacteria requires further investigation ( Thomanek et al, 2013 ).…”

The N-acyl homoserine-lactone depleted Rhizobium radiobacter mutant RrF4NM13 shows reduced growth-promoting and resistance-inducing activities in mono- and dicotyledonous plants

“…AHLs differ in length and composition of their acyl side chains. Molecules with chain lengths of 4-18 carbon atoms frequently contain a carbonyl (oxo) or hydroxyl (OH) substitution on the third carbon atom (Williams 2007;Thomanek et al 2013). Endofungal bacteria also produce AHLs as first shown for endobacteria of the zygomycete fungus Mortierella alpine A-178 (Kai et al 2012), where they may play a role in the establishment and/or maintenance of the symbiotic interaction with the zygomycete.…”

Morpholin-2-one Derivatives via Intramolecular Acid-Catalyzed Hydroamination

“…): 2823, 2801, 1717, 1522, 1112, 1017 cm -1 .1 H NMR (300 MHz, CDCl3): δ = 7.29 -7.24 (m, 4H), 7.15 (t, J = 6.2 Hz, 5H), 5.34 -5.11 (m, 1H), 4.24 (d, J = 5.4 Hz, 1H), 3.98 (t, J = 7.5 Hz, 1H), 3.75 (t, J = 7.7 Hz, 1H), 3.14 (dd, J = 13.9, 5.2 Hz, 1H), 3.02 (dd, J = 14.0, 6.6 Hz, 1H), 2.33 (s, 3H), 0.91 (d, J = 7.5 Hz, 3H) ppm 13. C NMR (126 MHz, CDCl3): δ = 171.0, 143.6, 136.7, 134.8, 129.6, 128.6, 127.2, 67.3, 56.5, 39.6, 21.7, 21.5, 10.2 ppm.…”

“…[α]D 20 -6.8 (c 1.5, CH2Cl2). IR (neat): 3304, 2911, 2820, 1720, 1698, 1287, 1165 cm -1 .1 H NMR (300 MHz, CDCl3): δ = 7.79 (d, J = 7.5 Hz, 2H), 7.63 (d, J = 7.4 Hz, 2H), 7.42 (t, J = 7.3 Hz, 2H), 7.34 (t, J = 7.4 Hz, 2H), 5.39 (d, J = 9.1 Hz, 1H), 5.02 (d, J = 7.9 Hz, 1H), 4.98 (s, 1H), 4.66 -4.53 (m, 2H), 4.45 -4.38 (m, 2H), 4.26 (t, J = 7.0 Hz, 1H), 1.99 -1.94 (m, 1H), 1.79 (s, 3H), 1.54 -1.39 (m, 1H), 1.33 -1.13 (m, 1H), 0.95 (d, J = 6.8 Hz, 3H), 0.93 (t, J = 7.8 Hz, 3H) ppm 13. C NMR (75 MHz, CDCl3): δ = 171.9, 156.2, 143.9, 141.3, 139.3), 127.7, 127.1, 125.1, 120.0, 113.9, 68.6, 67.0, 58.5, 47.2, 38.1, 25.0, 19.6, 15.6, 11.7 ppm.…”

“…13 C NMR (101 MHz, CDCl3): δ = 171 3,. 155.6, 139.2, 136.2, 135.7, 129.3, 128.7, 128.2, 128.1, 127.8, 127.2, 127.1, 113.9, 68.8, 67.0, 54.9, 38.3, 19.5 ppm.…”