J Genomics 2022; 10:61-68. doi:10.7150/jgen.75779 This volume

Research Paper

Draft Genomes of Symbiotic Frankia Strains AgB32 and AgKG'84/4 from Root Nodules of Alnus Glutinosa growing under Contrasted Environmental Conditions

Philippe Normand1✉, Petar Pujic1, Danis Abrouk1, Spandana Vemulapally2, Trina Guerra2, Camila Carlos-Shanley2, Dittmar Hahn2

1. Université Claude-Bernard Lyon 1, Université de Lyon, UMR 5557 CNRS Ecologie Microbienne, Villeurbanne, Cedex 69622, France.
2. Texas State University, Department of Biology, 601 University Drive, San Marcos, TX 78666, USA.

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Citation:
Normand P, Pujic P, Abrouk D, Vemulapally S, Guerra T, Carlos-Shanley C, Hahn D. Draft Genomes of Symbiotic Frankia Strains AgB32 and AgKG'84/4 from Root Nodules of Alnus Glutinosa growing under Contrasted Environmental Conditions. J Genomics 2022; 10:61-68. doi:10.7150/jgen.75779. Available from https://www.jgenomics.com/v10p0061.htm

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Abstract

Graphic abstract

The genomes of two nitrogen-fixing Frankia strains, AgB32 and AgKG'84/4, were isolated from spore-containing (spore+) and spore-free (spore-) root nodules of Alnus glutinosa, but they did not sporulate upon reinfection. The two strains are described as representatives of two novel candidate species. Phylogenomic and ANI analyses indicate that each strain represents a novel species within cluster 1, with genome sizes of 6.3 and 6.7 Mb smaller than or similar to those of other cultivated Alnus-infective cluster 1 strains. Genes essential for nitrogen-fixation, clusters of orthologous genes, secondary metabolite clusters and transcriptional regulators analyzed by comparative genomic analyses were typical of those from Alnus-infective cluster 1 cultivated strains in both genomes. Compared to other cultivated Alnus-infective strains with large genomes, those of AgB32 and AgKG'84/4 had lost 380 or 409 genes, among which one hup cluster, one shc gene and the gvp cluster, which indicates genome erosion is taking place in these two strains.

Keywords: Frankia, Actinorhizal symbiosis, genome, nitrogen-fixing frankiae, biosynthetic gene clusters