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Enhanced nodulation and symbiotic effectiveness of Medicago truncatula when co-inoculated with Pseudomonas fluorescens WSM3457 and Ensifer (Sinorhizobium) medicae WSM419

Fox, S.L., O'Hara, G.W. and Bräu, L. (2011) Enhanced nodulation and symbiotic effectiveness of Medicago truncatula when co-inoculated with Pseudomonas fluorescens WSM3457 and Ensifer (Sinorhizobium) medicae WSM419. Plant and Soil, 348 (1-2). pp. 245-254.

Link to Published Version: http://dx.doi.org/10.1007/s11104-011-0959-8
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Abstract

Aims: Low numbers of rhizobia in soil or inoculants delay nodulation and decrease symbiotic legume productivity. This study investigated the effect of co-inoculation with a helper bacterium, Pseudomonas fluorescens WSM3457 on the Medicago truncatula - Ensifer (Sinorhizobium) medicae WSM419 symbiosis challenged by a low inoculum dose. Methods: In a glasshouse experiment the effect of co-inoculation with WSM3457 on the kinetics of nodule initiation and development was assessed 5,7,10,14,1721, and 42 days after inoculation of M. truncatula cv. Caliph with 103 cells/plant of E. medicae WSM419. Results: Co-inoculated plants had enhanced rate of nodule initiation and development, greater numbers of larger crown nodules, and by day 42 accumulated more N than plants inoculated with E. medicae WSM419 alone. Nodule development was altered by co-inoculation. Approximately 25% of nodule initials on co-inoculated plants formed in closely associated pairs, young nodules were larger with multiple meristems and developed into cluster-like multi-lobed nodules compared to those on WSM419 inoculated plants. Molecular typing showed WSM3457 occupied a significant proportion of root nodules on co-inoculated plants. Conclusion: Co-inoculation with P. fluorescens WSM3457 enhanced symbiotic effectiveness of M. truncatula when inoculated with a low inoculum dose of E. medicae WSM419.

Publication Type: Journal Article
Murdoch Affiliation: Centre for Rhizobium Studies
School of Biological Sciences and Biotechnology
Publisher: Kluwer Academic Publishers
Copyright: © 2011 The Author(s).
URI: http://researchrepository.murdoch.edu.au/id/eprint/5834
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