Catherine Bellini, Umeå Plant Science Centre, Umeå University
Sara von Arnold, Plant Biology
Lecture hall A281, Uppsala BioCentre, Ultuna
14:00 - 15:00
Auxin is a key player in the hormone control that controls adventitious rooting

Adventitious roots (AR), also called shoot-born roots, are crucial for vegetative propagation of elite genotypes in horticulture and forestry. AR formation is a plastic polygenic trait controlled by multiple environmental and endogenous factors. The fine tuning of AR initiation in the Arabidopsis hypocotyl is regulated by a complex crosstalk between auxin and jasmonic acid (JA). This signaling pathway includes three AUXIN RESPONSE FACTOR genes (ARF6, ARF8 and ARF17) acting upstream of JA signaling. A genetic analysis shows that several null allele mutants in the Aux/IAA genes developed more AR than the wild type, suggesting that these genes are likely repressing AR initiation through the interaction with ARF6 and ARF8. The analysis by qPCR of the expression profile of these Aux/IAA genes revealed that they are upregulated in the hypocotyl compared to shoot and roots. In addition co-immunoprecipitation technique confirmed that at least three of the identified Aux/IAA proteins physically interact with ARF6 and/or ARF8. Our findings highlight novel molecular players in the control of AR initiation in Arabidopsis hypocotyl.