The Integration of Metabolite and Hormone Signalling Drives Seedling Development

• Main Author: Stokes, Michael
• Other Authors: Campbell, Malcolm M.
• Language: en_ca
• Published: 2013
• Subjects: Sugar; Folate; Chemical Genetics; Auxin; Development; 0309
• Online Access: http://hdl.handle.net/1807/43736

Sugars have a profound impact on plant biology, acting as structural components, signalling molecules, and sources of energy. As such, the availability of sugars has important implications for plant growth and development. Sugar levels rise and fall as part of a daily cycle, while cues from other environmental stimuli are also in flux. As sessile organisms in an ever-changing environment, plants must integrate signals from multiple pathways in order to promote the appropriate developmental responses. To uncover pathways that interact with sugars during seedling development, a chemical screen was performed in search of compounds that modify responses to sucrose. This screen identified an interaction between the folate inhibitor sulfamethoxazole (SMX) and sucrose that resulted in changes to auxin signalling and distribution. Synergy between sucrose and SMX was used to explore the effect of metabolic cues on auxin signalling during hypocotyl elongation. A second line of investigation explored whether sucrose and folates influence root meristem activity. Sucrose induced hormone signalling pathways that promote cell division and differentiation. Treatment with SMX perturbed the effect of sucrose on hormone networks that mediate growth, and resulted in a loss of meristem integrity. This study highlights the influence of metabolism on hormone signalling at the root apex, and its role in maintaining balance of a complex signalling network that drives root growth. These studies characterise an interaction between metabolic pathways that is integrated with hormone signalling during plant development. Taken together, they highlight a mechanism through which plant growth might be regulated by metabolism.