HYBRID EVENT: You can participate in person at Rome, Italy or Virtually from your home or work.
HYBRID EVENT
September 16-18, 2024 | Rome, Italy
GPMB 2017

Laura Fattorini

Laura Fattorini, Speaker at Plant Science Conferences
Sapienza University of Rome, Italy
Title : How does indole-3-butyric acid induce adventitious root formation in Arabidopsis thaliana thin cell layers?

Abstract:

Adventitious roots (ARs) are post-embryonic roots essential for plant survival and vegetative propagation via cuttings. In different types of explants, the auxin indole-3-acetic acid (IAA), and its natural precursor indole-3-butyric acid (IBA), when applied exogenously, are the main inducers of AR formation. In many cases, exogenous IBA is more effective in inducing ARs than exogenous IAA, but the reason needs investigation. Arabidopsis thaliana thin cell layers (TCLs) consist of stem inflorescence tissues external to the vascular system. Previous researches demonstrated that in TCLs excised from A. thaliana and tobacco exogenous IBA induces ARs when combined with kinetin (Falasca et al., Plant Cell Rep, 2004; Fattorini et al., Planta, 2009). However, in dark-grown A. thaliana seedlings IBA is able alone to induce AR formation (Veloccia et al., J Exp Bot, 2016). In cuttings as in planta, the endogenous IAA/IBA contents are determinant for the AR process, and differences in response to exogenous IAA/IBA may depend on differences in endogenous contents. It is unknown whether A. thaliana TCLs contain endogenous IAA/IBA at culture onset. Results showed that IAA and IBA were at undetectable levels at culture onset, and this was an optimal premise to investigate AR formation under the total control of exogenous auxin, revealing possible differences between IAA and IBA. The AR response of TCLs from various ecotypes, transgenic lines and knockout mutants showed that IBA was an AR inducer better than IAA. IBA positively affected IAA cellular influx, mediated by AUXIN RESISTANT1 (AUX1) and LIKE AUXIN RESISTANT3 (LAX3), and efflux, due to PIN-FORMED1 (PIN1), and expression of ANTHRANILATE SYNTHASE-alpha1 (ASA1), a gene of the tryptophan-dependent IAA biosynthesis. Results support that ASA1 and ANTHRANILATE SYNTHASE-beta1 (ASB1), the other subunit of the enzyme, are required for AR formation in the presence of exogenous IBA. The AR response of IBA-treated TCLs from ech2ibr10 mutant, blocked into IBA-to-IAA conversion, was strongly reduced, showing that IBA action is indirect, i.e. IBA acts mainly by conversion into IAA. Nitric oxide (NO), a downstream signal of IAA, but also a by-product of the conversion process, was early detected in IAA- and IBA-treated TCLs, but at higher levels in the latter ones. Altogether results showed that exogenous IBA induced AR formation in TCLs by conversion into IAA involving NO, IAA transport, and ASA1/ASB1-mediated IAA biosynthesis.

Biography:

Laura Fattorini was graduated in Natural Sciences at Sapienza University of Rome on 2006. She attended the Ph.D School in Botanical Sciences in the Department of Environmental Biology of the same University and, after three years, obtained the Doctoral Degree. During the following years she worked as PostDoc and her current position is RTDB Researcher. Her research experience focusses on hormonal and genetic control of root development and xylogenesis in plants and thin cell layers (TCLs), of Arabidopsis thaliana in particular. Besides, she investigated the effects of cadmium and arsenic on root development, quiescent centre activity and auxin transport and the effects of the endomychorrhizal symbiosis on cadmium and arsenic accumulation in adult plants of Nicotiana tabacum. She is co-author of 18 publications on scientific journals/book and 36 communications in national and international congresses.

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