Rhizobial genetic and genomic resources for sustainable agriculture
MacLean G. Kohlmeier
A * , Graham W. O’Hara A , Joshua P. Ramsay B and Jason J. Terpolilli A
A
B
MacLean Kohlmeier received his PhD from the University of Manitoba in 2020 with Prof. Ivan Oresnik. He is currently a Postdoctoral Research Fellow in Microbial Genomics in the Legume Rhizobium Sciences group at Murdoch University. His research interests include gene transfer events between soil bacteria, as well as carbon metabolism and transport, and how these features affect symbiotic establishment and efficiency. |
Graham O’Hara is Director of Murdoch University’s Legume Rhizobium Sciences centre in the Food Futures Institute, and co-curator of the International Legume Inoculant Genebank (ILIG). He has worked extensively in national and international projects on applied nitrogen fixation leading to the development and dissemination of inoculant rhizobia strains. His research interest is focussed on the soil ecology, mineral nutrition, physiology and stress tolerance of rhizobia, and how this affects their performance as inoculants in the field. |
Joshua Ramsay carried out his PhD in 2004–2008 at the University of Otago with Prof. Clive Ronson. He was then a University of Cambridge Herchel Smith Postdoctoral Fellow from 2008 to 2011 and a Health Sciences Career Development Fellow at the University of Otago. Ramsay started his own lab at Curtin University in 2013. Dr Ramsay’s investigations explore the effects of mobile genetic elements in both health related and agricultural contexts. In 2018, Dr Ramsay was awarded an ARC Future Fellowship and he is currently an Associate Professor in the Curtin Medical School and Curtin Health Innovation Research Institute. |
Jason Terpolilli is Research Director of Murdoch University’s Legume Rhizobium Sciences centre in the Food Futures Institute, and co-curator of ILIG. He works closely with colleagues across Australia on several projects aimed at increasing the application of effective nitrogen-fixing rhizobia for grain and pasture legumes. His main areas of research interest are in rhizobia genetics and biochemistry and in applying genomics to develop robust approaches to studying the evolution of these organisms and their effect on farming systems in the field. |
Abstract
Rhizobia are a diverse group of α- and β-proteobacteria that boost soil fertility by forming a nitrogen-fixing symbiosis with legumes, which is why legumes are grown in rotation with cereals in agriculture. Rhizobia that naturally populate Australian soils are largely incompatible with exotic agricultural legumes, therefore, compatible strains have been imported from all over the world for use as inoculants. An amalgamated collection of these strains, called the International Legume Inoculant Genebank (ILIG), has been established at Murdoch University, to provide a centralised strain storage facility and support rhizobial research and inoculant development (see http://ilig.murdoch.edu.au). The ILIG contains 11,558 strains representing 96 bacterial species from 778 legume species collected from >1200 locations across 100 countries. New and sometimes inefficient rhizobia evolve in the field following legume inoculation, through horizontal symbiosis gene transfer from inoculants to soil bacteria. To provide a benchmark to monitor and assess the impact of this evolution, all commercial Australian inoculant strains were genome sequenced and these data made available (PRJNA783123, see https://www.ncbi.nlm.nih.gov/bioproject/PRJNA783123/). These data, and the further sequencing of the >11,000 historical strains in the ILIG, will increase our understanding of rhizobial evolution and diversity and provide the backbone for efforts to safeguard Australia’s legume inoculation program.
Keywords: horizontal gene transfer, inoculant, legume, rhizobia, sequencing, symbiosis.
MacLean Kohlmeier received his PhD from the University of Manitoba in 2020 with Prof. Ivan Oresnik. He is currently a Postdoctoral Research Fellow in Microbial Genomics in the Legume Rhizobium Sciences group at Murdoch University. His research interests include gene transfer events between soil bacteria, as well as carbon metabolism and transport, and how these features affect symbiotic establishment and efficiency. |
Graham O’Hara is Director of Murdoch University’s Legume Rhizobium Sciences centre in the Food Futures Institute, and co-curator of the International Legume Inoculant Genebank (ILIG). He has worked extensively in national and international projects on applied nitrogen fixation leading to the development and dissemination of inoculant rhizobia strains. His research interest is focussed on the soil ecology, mineral nutrition, physiology and stress tolerance of rhizobia, and how this affects their performance as inoculants in the field. |
Joshua Ramsay carried out his PhD in 2004–2008 at the University of Otago with Prof. Clive Ronson. He was then a University of Cambridge Herchel Smith Postdoctoral Fellow from 2008 to 2011 and a Health Sciences Career Development Fellow at the University of Otago. Ramsay started his own lab at Curtin University in 2013. Dr Ramsay’s investigations explore the effects of mobile genetic elements in both health related and agricultural contexts. In 2018, Dr Ramsay was awarded an ARC Future Fellowship and he is currently an Associate Professor in the Curtin Medical School and Curtin Health Innovation Research Institute. |
Jason Terpolilli is Research Director of Murdoch University’s Legume Rhizobium Sciences centre in the Food Futures Institute, and co-curator of ILIG. He works closely with colleagues across Australia on several projects aimed at increasing the application of effective nitrogen-fixing rhizobia for grain and pasture legumes. His main areas of research interest are in rhizobia genetics and biochemistry and in applying genomics to develop robust approaches to studying the evolution of these organisms and their effect on farming systems in the field. |
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