摘要

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. 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. 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. 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.

  • 出版日期2011-11