A re-appraisal of the biology and terminology describing rhizobial strain success in nodule occupancy of legumes in agriculture
Document Type
Article
Publication Date
9-10-2011
Journal Title
Plant and Soil
ISSN
0032-079X eISSN: 1573-5036
Keywords
Legumes, Nitrogen fixation, Rhizobia, Effectiveness, Selective nodulation
Disciplines
Agronomy and Crop Sciences
Abstract
Aim
To ensure that the majority of nodules on a legume are occupied by the inoculant strain poses a significant challenge to maximising nitrogen fixation in agricultural settings. The aim of this review is to establish a set of common terms with which to classify and interrogate experiments that investigate nodule occupancy in legumes.
Results
At least six different terminologies have been developed to discuss experimental outcomes where legumes have access to more than one rhizobial strain. In this review we nominate a set of preferred terms: promiscuous, exclusive, selective and non-selective nodulation in an attempt to provide conformity to the general scientific pursuit of understanding the circumstances leading to nodule occupancy in legumes when more than one strain has the opportunity to form the nodule.
Discussion
To maximise nitrogen fixation from legumes, a primary challenge is to prevent rhizobia resident in the soil from dominating nodule occupation, since whilst they may be numerically dominant, they are often not optimally matched for nitrogen fixation with the introduced legume. It is apparent, however, that at times the legume host is able to preferentially enter into symbiosis with a fully effective strain, even if an ineffective strain is present and numerically dominant.
Conclusion
This manuscript reviews the terminology currently applied to nodulation outcomes in introduced legume symbioses where more than one strain type is available to infect the plant. We suggest adoption of a more stringent terminology as the research discipline matures to exploit genome sequence information. We have suggested the term “selective nodulation” to describe certain nodulation outcomes that are not based upon numerical supremacy.
Recommended Citation
Yates, R.J., Howieson, J.G., Reeve, W.G. et al. A re-appraisal of the biology and terminology describing rhizobial strain success in nodule occupancy of legumes in agriculture. Plant Soil 348, 255–267 (2011). https://doi.org/10.1007/s11104-011-0971-z
