Phyllobacterium trifolii sp. nov., nodulating Trifolium and Lupinus in Spanish soils

Abstract

Bacterial strain PETP02 T was isolated from nodules of Trifolium pratense growing in a Spanish soil. Phylogenetic analysis of the 16S rRNA gene sequence showed that this strain represents a member of the genus Phyllobacterium. However, divergence found with the 16S rRNA gene sequence of the single recognized species of this genus, Phyllobacterium myrsinacearum, indicated that strain PETP02 T belongs to a different species. The results of DNA-DNA hybridization, phenotypic tests and fatty acid analyses confirmed that this strain represents a novel species of the genus Phyllobacterium, for which the name Phyllobacterium trifolii sp. nov. is proposed. The type strain is PETP02 T (=LMG 22712 T =CECT 7015 T). This strain was strictly aerobic and used several carbohydrates as carbon source. It was not able to reduce nitrate. Aesculin hydrolysis was negative. It did not produce urease, arginine dihydrolase, gelatinase or b-galactosidase. The DNA G+C content was 56?4 mol%. The nodD gene of this strain showed a sequence closely related to those of strains able to nodulate Lupinus. Infectivity tests showed that this strain is able to produce nodules in both Trifolium repens and Lupinus albus.

A large diversity of non-rhizobial endophytes found in legume root nodules in Flanders (Belgium)

“…Plants house several endophytes within their tissues and multiple studies have reported the presence of endophytes in legumes (Muresu et al, 2008;Ibañez et al, 2009;Muresu et al, 2010). One of the genera in our study, Phyllobacterium (Table 1) is a known nodule endosymbiont and is capable of fixing nitrogen (Valverde et al, 2005;Baimiev et al, 2007). However, in our study no symbiosis or nitrogen fixation related genes were detected for the isolates of this genus.…”

“…However, this needs to be confirmed using authentication experiments (Howieson et al, 1995). Previous studies indicate that endophytes can have three main functions inside root nodules, firstly as true rhizobial endosymbionts capable of inducing nodulation and performing nitrogen fixation (Valverde et al, 2005;Ardley et al, 2012). Secondly, as helper bacteria increasing plant health and/or yield when co-inoculated with rhizobia (Annapurna et al, 2013;Tariq et al, 2014), and finally, as opportunistic endophytes thriving in this nitrogen riche nodule environment (Dudeja et al, 2012).…”

Emended description of the genus Phyllobacterium and description of four novel species associated with plant roots: Phyllobacterium bourgognense sp. nov., Phyllobacterium ifriqiyense sp. nov., Phyllobacterium leguminum sp. nov. and Phyllobacterium brassicacearum sp. nov.

“…The genus includes P. myrsinacearum and two recently described species, Phyllobacterium trifolii (Valverde et al, 2005) and Phyllobacterium catacumbae (Jurado et al, 2005).…”

Utilization of hexamethylenetetramine (urotropine) by bacteria and yeasts

“…Lane M is a DGGE marker 1447 tested). One of these strains had been identified as Phyllobacterium trifolii (Valverde et al 2005, GenBank accession number AY786080); the other one is an uncultured Phyllobacterium strain (Barbieri et al 2005, GenBank Accession Number AY599681). Attempts were made to isolate these by streaking on a selective medium, i.e.…”