J Integr Plant Biol. ›› 2014, Vol. 56 ›› Issue (12): 1118-1124.DOI: 10.1111/jipb.12231

• Minireview • Previous Articles     Next Articles

Split-root systems applied to the study of the legume-rhizobial symbiosis: What have we learned?

Estíbaliz Larrainzar1, Erena Gil-Quintana1, Cesar Arrese-Igor1, Esther M. González1 and Daniel Marino2,3*   

  1. 1Department of Environmental Sciences, Public University of Navarra, Pamplona, Spain
    2Department of Plant Biology and Ecology, University of the Basque Country UPV/EHU, Bilbao, Spain
    3Ikerbasque, Basque Foundation for Science, Bilbao, Spain
  • Received:2014-03-12 Accepted:2014-06-22 Published:2014-06-26
  • About author:*Correspondence: E-mail: daniel.marino@ehu.es


Split-root system (SRS) approaches allow the differential treatment of separate and independent root systems, while sharing a common aerial part. As such, SRS is a useful tool for the discrimination of systemic (shoot origin) versus local (root/nodule origin) regulation mechanisms. This type of approach is particularly useful when studying the complex regulatory mechanisms governing the symbiosis established between legumes and Rhizobium bacteria. The current work provides an overview of the main insights gained from the application of SRS approaches to understand how nodule number (nodulation autoregulation) and nitrogen fixation are controlled both under non-stressful conditions and in response to a variety of stresses. Nodule number appears to be mainly controlled at the systemic level through a signal which is produced by nodule/root tissue, translocated to the shoot, and transmitted back to the root system, involving shoot Leu-rich repeat receptor-like kinases. In contrast, both local and systemic mechanisms have been shown to operate for the regulation of nitrogenase activity in nodules. Under drought and heavy metal stress, the regulation is mostly local, whereas the application of exogenous nitrogen seems to exert a regulation of nitrogen fixation both at the local and systemic levels.


Larrainzar E, Gil‐Quintana E, Arrese‐Igor C, González EM, Marino D (2014) Split‐root systems applied to the study of the legume‐rhizobial symbiosis: What have we learned? J Integr Plant Biol 56: 1118–1124. doi: 10.1111/jipb.12231

Key words: legume-rhizobia, nitrogen fixation, nodulation, split-root system, symbiosis

Editorial Office, Journal of Integrative Plant Biology, Institute of Botany, CAS
No. 20 Nanxincun, Xiangshan, Beijing 100093, China
Tel: +86 10 6283 6133 Fax: +86 10 8259 2636 E-mail: jipb@ibcas.ac.cn
Copyright © 2022 by the Institute of Botany, the Chinese Academy of Sciences
Online ISSN: 1744-7909 Print ISSN: 1672-9072 CN: 11-5067/Q