Adventitious roots (ARs) are post-embryonic roots arising from non-pericycle tissues in primary root (PR) and various tissues in aerial organs. ARs are essential for successful vegetative propagation. Several protocols for AR induction were developed in Arabidopsis thaliana, in planta and in in vitro systems, e.g. stem thin cell layer (TCL) culture, which allow to study AR formation in a limited cell context. ARs are controlled by multiple factors, and auxin is a central player. Exogenous auxin is essential for ARs in TCLs. Ethylene could be another hormone involved, but presently there are many unresolved questions concerning its role, and in A. thaliana available data are in contrast. There is information about lateral roots (LRs), because an inhibitory effect of ACC (1- aminocyclopropane-1-carboxylic acid), direct ethylene precursor, on their formation was reported, but low concentrations stimulate the process (Negi et al, 2008; Ivanchenko et al, 2008). The Research studied ethylene effects, and the relationship with auxin, on AR formation in TCLs. Wild type TCLs were treated with various ACC concentrations. Significant reduction in AR number per TCL only occurred with 0.1μM, showing that specific ethylene levels might regulate AR formation. Because a relationship between auxin biosynthesis and ethylene was reported for the PR (Stepanova et al, 2005), TCLs of the double mutant wei2wei7, blocked in auxin biosynthesis, were grown with/without 0.1μM ACC. The number of ARs/TCL in this mutant was further reduced without ACC in comparison with the wt, demonstrating that endogenous auxin biosynthesis cooperates with exogenous auxin input on the AR formation. In this mutant no significant change in AR number was caused by ACC addition, showing that the effect of ethylene biosynthesis on AR response depends on auxin biosynthesis. TCLs were also excised from the ethylene insensitive mutants ein2-1 and ein3eil1 and cultured with/without 0.1μM ACC to verify whether ethylene signalling was also involved. In both mutants, no change in AR number/TCL occurred with/without ACC addition, and in both treatments ARs strongly elongated and showed a lot of LRs. All together results suggest that specific ethylene levels are involved in AR formation from TCLs possibly through a regulation of auxin biosynthesis, and ethylene perception also affects AR development and branching.
Ethylene role in adventitious root formation in Arabidopsis thaliana thin cell layers / Veloccia, Angela; Fattorini, Laura; DELLA ROVERE, Federica; Falasca, Giuseppina; Altamura, Maria Maddalena. - ELETTRONICO. - (2014), pp. 63-63. (Intervento presentato al convegno 7th International Symposium on Root Development: Adventitious, lateral & primary roots - at the crossroads of genome, environment & technology tenutosi a Weimar, Germania nel 15-19 settembre 2014).
Ethylene role in adventitious root formation in Arabidopsis thaliana thin cell layers
VELOCCIA, ANGELA;FATTORINI, LAURA;DELLA ROVERE, Federica;FALASCA, Giuseppina;ALTAMURA, Maria Maddalena
2014
Abstract
Adventitious roots (ARs) are post-embryonic roots arising from non-pericycle tissues in primary root (PR) and various tissues in aerial organs. ARs are essential for successful vegetative propagation. Several protocols for AR induction were developed in Arabidopsis thaliana, in planta and in in vitro systems, e.g. stem thin cell layer (TCL) culture, which allow to study AR formation in a limited cell context. ARs are controlled by multiple factors, and auxin is a central player. Exogenous auxin is essential for ARs in TCLs. Ethylene could be another hormone involved, but presently there are many unresolved questions concerning its role, and in A. thaliana available data are in contrast. There is information about lateral roots (LRs), because an inhibitory effect of ACC (1- aminocyclopropane-1-carboxylic acid), direct ethylene precursor, on their formation was reported, but low concentrations stimulate the process (Negi et al, 2008; Ivanchenko et al, 2008). The Research studied ethylene effects, and the relationship with auxin, on AR formation in TCLs. Wild type TCLs were treated with various ACC concentrations. Significant reduction in AR number per TCL only occurred with 0.1μM, showing that specific ethylene levels might regulate AR formation. Because a relationship between auxin biosynthesis and ethylene was reported for the PR (Stepanova et al, 2005), TCLs of the double mutant wei2wei7, blocked in auxin biosynthesis, were grown with/without 0.1μM ACC. The number of ARs/TCL in this mutant was further reduced without ACC in comparison with the wt, demonstrating that endogenous auxin biosynthesis cooperates with exogenous auxin input on the AR formation. In this mutant no significant change in AR number was caused by ACC addition, showing that the effect of ethylene biosynthesis on AR response depends on auxin biosynthesis. TCLs were also excised from the ethylene insensitive mutants ein2-1 and ein3eil1 and cultured with/without 0.1μM ACC to verify whether ethylene signalling was also involved. In both mutants, no change in AR number/TCL occurred with/without ACC addition, and in both treatments ARs strongly elongated and showed a lot of LRs. All together results suggest that specific ethylene levels are involved in AR formation from TCLs possibly through a regulation of auxin biosynthesis, and ethylene perception also affects AR development and branching.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
