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CSB Special Seminar: Dr. Hiroyuki Kasahara, RIKEN Center for Sustainable Resource Science
July 31, 2015 @ 2:00 pm - 3:00 pm
CSB Special Seminar
Dr. Hiroyuki Kasahara
RIKEN Center for Sustainable Resource Science
“Distinct Characteristics of IAA and PAA, Two Natural Auxins in Plants”
Friday, July 31, 2015
Earth Sciences Centre, Room 3087, 2-3 p.m.
The phytohormone auxin plays a central role in many aspects of plant growth and development. IAA is the most studied natural auxin that possesses the property of polar transport in plants. Phenylacetic acid (PAA) has also been recognized as a natural auxin, but its role in plant growth and development remains unclear. Recently, we showed that IAA and PAA have overlapping regulatory roles but distinct transport characteristics as auxins in plants. PAA is widely distributed in vascular and non-vascular plants. Although the biological activities of PAA are lower than those of IAA, the endogenous levels of PAA are much higher than those of IAA in various plant tissues in Arabidopsis. PAA and IAA can regulate the same set of auxin-responsive genes through the TIR1/AFB-Aux/IAA pathway in Arabidopsis. Interestingly, IAA actively forms concentration gradients in maize coleoptiles in response to gravitropic stimulation, whereas PAA does not, indicating that PAA is not actively transported in a polar manner. Our results provide new insights into the regulation of plant growth and development by different types of auxins.
Host: Eiji Nambara <eiji.nambara@utoronto.ca>