Abstract
•Plants that form root-nodule symbioses are within a monophyletic ‘nitrogen-fixing’ clade and associated signalling processes are shared with the arbuscular mycorrhizal symbiosis. Central to symbiotic signalling are nuclear-associated oscillations in calcium ions (Ca2+), occurring in the root hairs of several legume species in response to the rhizobial Nod factor signal.
•In this study we expanded the species analysed for activation of Ca2+ oscillations, including non-leguminous species within the nitrogen-fixing clade.
•We showed that Ca2+ oscillations are a common feature of legumes in their association with rhizobia, while Cercis, a non-nodulating legume, does not show Ca2+ oscillations in response to Nod factors from Sinorhizobium fredii NGR234. Parasponia andersonii, a non-legume that can associate with rhizobia, showed Nod factor-induced calcium oscillations to S. fredii NGR234 Nod factors, but its non-nodulating sister species, Trema tomentosa, did not. Also within the nitrogen-fixing clade are actinorhizal species that associate with Frankia bacteria and we showed that Alnus glutinosa induces Ca2+ oscillations in root hairs in response to exudates from Frankia alni, but not to S. fredii NGR234 Nod factors.
•We conclude that the ability to mount Ca2+ oscillations in response to symbiotic bacteria is a common feature of nodulating species within the nitrogen-fixing clade.
Original language | English |
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Pages (from-to) | 551-558 |
Journal | New Phytologist |
Volume | 207 |
DOIs | |
Publication status | Published - 2015 |
Keywords
- Actinorhizal
- Calcium oscillations
- Frankia
- Legumes
- Nitrogen-fixing clade
- Nodulation
- Parasponia
- Symbiotic signalling