Mendel University in Brno 

Keynote Lecture 7: Roles of Cytokinin Response Factors in different environmental stress responses

Aaron Rashotte [a]

[a] Department of Biological Sciences, Auburn University, 101 Rouse Life Sciences Bldg. Auburn University, AL 36849 USA

Cytokinin is a plant hormone well-known to be involved with plant growth and developmental processes with an increasing evidence of involvement in environmental stress responses. Cytokinin Response Factors or CRFs are a group of transcription factors identified with connections to both cytokinin and abiotic stress. Using transgenic lines with altered CRF levels we have examined the role that CRFs play in different abiotic stress responses, including oxidative, cold, and salt stress response. This has been done in experiments examining different physiological measurements, transcriptome profiling, and measurements of cytokinin levels after changes in stress response. This work has revealed that specific stress responses of CRFs appears to mirror phylogenetic groupings of these proteins into clades that have deeply distinct evolutionary lineages that are conserved throughout Angiosperms. Sequence-based analysis of promoter elements from each CRF Clade across plants support these findings. Arabidopsis based work suggest roles of different clades in different abiotic stress responses: Clade I – Salt and Osmotic, Clade II – Cold, and Clade III – Oxidative.