UPSC Cutting-Edge Seminar: Katharina Markmann
Date:
Friday, May 23, 2025 10:00 - 11:00
Duration:
1 Hour
Categories:
Location:
UPSC Cutting-Edge Seminar
Katharina Markmann
University of Würzburg, Germany
Title: Systemic control of and root architecture and symbiotic competence through mobile miRNAs
Host: Stephan Wenkel
Abstract:
Authors: Daniela Tsikou, Zhe Yan, Moritz Sexauer, Hemal Bhasin & Katharina Markmann
Legumes balance symbiotic interactions with nitrogen-fixing rhizobial bacteria via a systemic feedback system tightly controlling rates of bacterial infection and nodulation events. This host regulatory system, termed autoregulation of nodulation (AON), prevents nutritional misbalances and is key to maintaining the association at a mutualistic state. We identified a riboregulator, the micro RNA miR2111, that undergoes shoot-to-root translocation to control infection (1) through specific post-transcriptional regulation of the Kelch-repeat F-box gene TOO MUCH LOVE (TML), a root-acting repressor of infection and nodulation (2). Our results reveal miR2111 as a key systemic activator of symbiosis that maintains a susceptible default status in noninfected hosts. The regulon miR2111-TML is conserved across dicot land plant lineages, including the asymbiotic ruderal Arabidopsis thaliana. Plants adapt their root system architecure to soil nitrogen availability in a process called foraging. Our data suggest that apart from its role in symbiosis control, miR2111 acts as a mobile shoot signal translocating to the root in a nitrogen homeostasis-dependent manner to control lateral root formation (3). Comparative investigations in the model legume Lotus japonicus and Arabidopsis thaliana identify this regulon as an essential, evolutionarily stable factor in shoot dependent adaptation of root organ formation in response to nitrate availability in plants of divergent lifestyles (3).
(1) Tsikou et al. (2018) Science 362: 233-236
(2) Takahara et al. (2013) Plant & Cell Physiology 54: 433-447
(3) Sexauer et al. (2023) Nature Communications 14: 8083
Katharina Markmann
University of Würzburg, Germany
Title: Systemic control of and root architecture and symbiotic competence through mobile miRNAs
Host: Stephan Wenkel
Abstract:
Authors: Daniela Tsikou, Zhe Yan, Moritz Sexauer, Hemal Bhasin & Katharina Markmann
Legumes balance symbiotic interactions with nitrogen-fixing rhizobial bacteria via a systemic feedback system tightly controlling rates of bacterial infection and nodulation events. This host regulatory system, termed autoregulation of nodulation (AON), prevents nutritional misbalances and is key to maintaining the association at a mutualistic state. We identified a riboregulator, the micro RNA miR2111, that undergoes shoot-to-root translocation to control infection (1) through specific post-transcriptional regulation of the Kelch-repeat F-box gene TOO MUCH LOVE (TML), a root-acting repressor of infection and nodulation (2). Our results reveal miR2111 as a key systemic activator of symbiosis that maintains a susceptible default status in noninfected hosts. The regulon miR2111-TML is conserved across dicot land plant lineages, including the asymbiotic ruderal Arabidopsis thaliana. Plants adapt their root system architecure to soil nitrogen availability in a process called foraging. Our data suggest that apart from its role in symbiosis control, miR2111 acts as a mobile shoot signal translocating to the root in a nitrogen homeostasis-dependent manner to control lateral root formation (3). Comparative investigations in the model legume Lotus japonicus and Arabidopsis thaliana identify this regulon as an essential, evolutionarily stable factor in shoot dependent adaptation of root organ formation in response to nitrate availability in plants of divergent lifestyles (3).
(1) Tsikou et al. (2018) Science 362: 233-236
(2) Takahara et al. (2013) Plant & Cell Physiology 54: 433-447
(3) Sexauer et al. (2023) Nature Communications 14: 8083