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Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Powell, Adrian F. [1], Doyle, Jeff J. [2].

Nodulation symbioses, signaling, and allopolyploidy in Glycine subgenus Glycine (Leguminosae).

In recent years, genomic studies have led to interest in the potential role of polyploidy in the refinement and evolution of legume-rhizobia nodulation symbioses, highlighting the need for more direct studies of the relationship between these two phenomena. The present study examines the effects of allopolyploidy on nodulation symbiosis between rhizobial bacteria and members of the Glycine subgenus Glycine allopolyploid complex. This complex provides a system approaching a replicated natural experiment in allopolyploidy, in which a small number of diploid progenitor species contributed genomes to several independently and relatively recently formed polyploids. Using this experimental system, our aims are to (1) characterize the symbiotic interactions that are possible for allopolyploids relative to their diploid progenitors and (2) elucidate the alterations to plant symbiotic signalling that result from allopolyploid genome duplication. In inoculation trials, allopolyploids responded differently than diploid progenitors in terms of biomass, nodule number and other measures, and appear to be capable of nodulation with a greater number of tested strains. The specificity of rhizobial symbiosis is governed by several stages of signal, response, and interaction, each of which requires compatibility. Significant differences in flavonoid signalling compounds between allopolyploids and their diploid progenitors were observed and allopolyploidy had variable effects on overall exudate profiles, as assessed by PCA and Random Forest analyses. Analyses of expression and sequence diversity in genes encoding plant Nod factor receptors, which participate in perception of rhizobial signals induced by flavonoids, also showed evidence of differential homoeologue expression patterns following genome duplication. Thus, we find evidence of differing potential for symbiotic rhizobial interactions in allopolyploids as compared to their diploid progenitors, as well as the alteration of signalling mechanisms that give rise to these interactions.

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1 - Cornell University, Plant Biology, 412 Mann Library, Ithaca, NY, 14850, USA
2 - Cornell University, 412 Mann Library Building, Ithaca, NY, 14853-4301, USA


Presentation Type: Oral Paper:Papers for Topics
Session: 36
Location: Salon 5/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:45 AM
Number: 36004
Abstract ID:443
Candidate for Awards:None

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