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Biogeography of nodulated legumes and their nitrogen‐fixing symbionts
Author(s) -
Sprent Janet I.,
Ardley Julie,
James Euan K.
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14474
Subject(s) - rhizobia , biology , context (archaeology) , nitrogen fixation , equator , biogeography , symbiosis , ecology , taxonomy (biology) , latitude , botany , geography , paleontology , bacteria , geodesy
ContentsSummary 40 I. Introduction 40 II. Recent changes in the taxonomy of legume genera 41 III. Latitudinal variations in the distribution of nodulated legumes 44 IV. Longitudinal variations in the distribution of nodulated legumes 48 V. Evolution of legume nodulation 49 VI. Legume‐nodulating bacteria – rhizobial diversity in a geographical context 49 VII. Host plant control of rhizobia – the Inverted Repeat Lacking Clade (IRLC) legumes 52 VIII. Conclusions and outstanding problems 53Acknowledgements 53References 53Summary In the last decade, analyses of both molecular and morphological characters, including nodulation, have led to major changes in our understanding of legume taxonomy. In parallel there has been an explosion in the number of genera and species of rhizobia known to nodulate legumes. No attempt has been made to link these two sets of data or to consider them in a biogeographical context. This review aims to do this by relating the data to the evolution of the two partners: it highlights both longitudinal and latitudinal trends and considers these in relation to the location of major land masses over geological time. Australia is identified as being a special case and latitudes north of the equator as being pivotal in the evolution of highly specialized systems in which the differentiated rhizobia effectively become ammonia factories. However, there are still many gaps to be filled before legume nodulation is sufficiently understood to be managed for the benefit of a world in which climate change is rife.