Micromonospora cremea sp. nov. and Micromonospora zamorensis sp. nov., isolated from the rhizosphere of Pisum sativum

Abstract

Three actinobacterial strains, CR30T, CR36 and CR38T, were isolated from rhizosphere soil of Pisum sativum plants collected in Spain. The strains were filamentous, Gram-stain-positive and produced single spores. Phylogenetic, chemotaxonomic and morphological analyses confirmed that the three strains belonged to the genus Micromonospora . 16S rRNA gene sequence analysis of strains CR30T and CR36 showed a close relationship to Micromonospora coriariae NAR01T (99.3 % similarity) while strain CR38T had a similarity of 99.0 % with Micromonospora saelicesensis Lupac 09T. In addition, gyrB gene phylogeny clearly differentiated the novel isolates from recognized Micromonospora species. DNA–DNA hybridization, BOX-PCR and ARDRA profiles confirmed that these strains represent novel genomic species. The cell-wall peptidoglycan of strains CR30T and CR38T contained meso-diaminopimelic acid. Both strains had MK-10(H4) as the main menaquinone and a phospholipid type II pattern. An array of physiological tests also differentiated the isolates from their closest neighbours. Considering all the data obtained, it is proposed that strains CR30T and CR36 represent a novel species under the name Micromonospora cremea sp. nov. (type strain CR30T = CECT 7891T = DSM 45599T), whereas CR38T represents a second novel species, for which the name Micromonospora zamorensis sp. nov. is proposed, with CR38T ( = CECT 7892T = DSM 45600T) as the type strain.

Micromonospora from nitrogen fixing nodules of alfalfa (Medicago sativa L.). A new promising Plant Probiotic Bacteria.

“…It should also be noted that none of them were clones of one another, supporting the idea of the existence of high genetic diversity among Micromonospora strains in legume root nodules. Our results are coherent with data from Lupinus angustifolius and Pisum sativum root nodules1315.…”

“…Neither of the strains grew in nitrogen-free media or reduced acetylene under micro-aerobic conditions. Incorporation of 15N into the microbial biomass or alfalfa tissues was not detected. Also, attempts to amplify putative nif H genes in these strains were unsuccessful.…”

“…Recently, the first intranodular actinobacteria have been described56, but from the first description in this environment, the number of actinomycetes found has increased and in fact even new species have been described. Examples of these new findings inside nodules are Curtobacterium in Trifolium and Ornithopus 78; Microbacterium in Acacia , Glycyrrhiza , Medicago and Ornithopus 7891011; Micromonospora in several legumes1213141516; Streptomyces in Sphaerophisa 17 and others. Notably Micromonospora , which has been isolated from more than 20 different widely distributed plant species seem to have good potential as a plant-probiotic bacteria (PPB), although this remains to be studied in depth.…”

“…At our laboratory, strains of Micromonospora have been isolated from healthy plant nodules in a variety of genera of leguminous plants including M. sativa (alfalfa)12131516. Alfalfa is one of the most widely adapted agronomic crops and a cheap source of protein-rich forage with high digestibility, which is a valuable trait in economical animal husbandry.…”

Micromonospora ureilytica sp. nov., Micromonospora noduli sp. nov. and Micromonospora vinacea sp. nov., isolated from Pisum sativum nodules

“…Cell preparation and protocols for whole-cell sugars, isomers of diaminopimelic acid, menaquinones, polar lipids and fatty acids were carried out as explained previously (Carro et al, 2012a).…”