Identification of Mebendazole as an ethylene signaling activator reveals a role of ethylene signaling in the regulation of lateral root angles

Abstract

The lateral root angle or gravitropic set-point angle (GSA) is an important trait for root system architecture (RSA) that determines the radial expansion of the root system. The GSA therefore plays a crucial role in the ability of plants to access nutrients and water in the soil. Despite its importance, only few regulatory pathways and mechanisms that determine GSA are known, and these mostly relate to auxin and cytokinin pathways. Here, we report the identification of a small molecule that modulates GSA in Arabidopsis thaliana roots and acts via the activation of ethylene signaling. We uncover that this small molecule Mebendazole (MBZ) directly acts on the serine/threonine protein kinase CTR1, which is a negative regulator of ethylene signaling. Our study not only reveals that the ethylene signaling pathway is essential for GSA regulation, but it also identifies a small molecular modulator of RSA and the first specific activator of ethylene signaling.

Subcellular dynamics of ethylene signaling drive plant plasticity to growth and stress

“…In addition to the plasma membrane, cytosol, P-body, and nucleus, CTR1 may localize to other compartments, including peroxisomes, Golgi, chloroplasts, and cytoskeleton, potentially through interactions with organelle-tethered or targeted proteins (Figure 2 The recent identification of a small molecule that inhibits CTR1 activity could also provide an additional valuable tool to further dissect the subcellular-specific role of CTR1 in plants. [75] In addition to addressing the aforementioned questions, investigating ethylene signaling in Arabidopsis and its comparative analysis with other plant species, including economically important crop plants such as rice, also holds significant potential for novel discoveries that broaden our understanding of this critical pathway across the plant king-…”

“…The recent identification of a small molecule that inhibits CTR1 activity could also provide an additional valuable tool to further dissect the subcellular‐specific role of CTR1 in plants. [ 75 ] In addition to addressing the aforementioned questions, investigating ethylene signaling in Arabidopsis and its comparative analysis with other plant species, including economically important crop plants such as rice, also holds significant potential for novel discoveries that broaden our understanding of this critical pathway across the plant kingdom. Comparative studies could reveal conserved mechanisms as well as species‐specific adaptations, shedding light on the evolutionary trajectories of ethylene signaling components and their functional diversification.…”