Paenibacillus allorhizosphaerae sp. nov., from soil of the rhizosphere of Zea mays

Paenibacillus plantiphilus sp. nov. from the plant environment of Zea mays

A Gram-strain positive, aerobic, endospore-forming bacterial strain (JJ-246^T) was isolated from the rhizosphere of Zea mays. The 16S rRNA gene sequence similarity comparisons showed a most closely relationship to Paenibacillus oenotherae DT7-4^T (98.4%) and Paenibacillus xanthinolyticus 11N27^T (98.0%). The pairwise average nucleotide identity and digital DNA-DNA hybridisation values of the JJ-246^T genome assembly against publicly available Paenibacillus type strain genomes were below 82% and 33%, respectively. The draft genome of JJ-246^T shared many putative plant-beneficial functions contributing (PBFC) genes, related to plant root colonisation, oxidative stress protection, degradation of aromatic compounds, plant growth-promoting traits, disease resistance, drug and heavy metal resistance, and nutrient acquisition. The quinone system of strain JJ-246^T, the polar lipid profile and the major fatty acids were congruent with those reported for members of the genus Paenibacillus. JJ-246^T was shown to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus plantiphilus sp. nov. is proposed, with JJ-246^T (= LMG 32093^T = CCM 9089^T = CIP 111893^T) as the type strain.

Fine scale sampling reveals early differentiation of rhizosphere microbiome from bulk soil in young Brachypodium plant roots

For a deeper and comprehensive understanding of the composition and function of rhizosphere microbiomes, we need to focus at the scale of individual roots in standardized growth containers. Root exudation patterns are known to vary along distinct parts of the root even in juvenile plants giving rise to spatially distinct microbial niches. To address this, we analyzed the microbial community from two spatially distinct zones of the developing primary root (tip and base) in young Brachypodium distachyon grown in natural soil using standardized fabricated ecosystems known as EcoFABs as well as in more conventional pot and tubes. 16S rRNA based community analysis showed a strong rhizosphere effect resulting in significant enrichment of several OTUs belonging to Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. However, microbial community composition did not differ between root tips and root base or across different growth containers. Functional analysis of bulk metagenomics revealed significant differences between root tips and bulk soil. The genes associated with different metabolic pathways and root colonization were enriched in root tips. On the other hand, genes associated with nutrient-limitation and environmental stress were prominent in the bulk soil compared to root tips, implying the absence of easily available, labile carbon and nutrients in bulk soil relative to roots. Such insights into the relationships between developing root and microbial communities are critical for judicious understanding of plant-microbe interactions in early developmental stages of plants.

Paenibacillus vietnamensis sp. nov., isolated from the rhizosphere soil of Arachis hypogaea

A novel bacterial strain, N4T, was isolated from the soil of a groundnut Arachis hypogaea field in Nghean province, Vietnam. The phylogenetic, chemotaxonomic and phenotypic characteristics of this strain were determined. Cells of strain N4T were Gram-negative, aerobic, endospore-forming and rod-shaped. Strain N4T grew at 20–37 °C (optimum, 30 °C), pH 6–10 (optimum, pH 7) and 0–5 % NaCl (optimum, 0 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain N4T belonged to the genus Paenibacillus and was closely related to Paenibacillus harenae B519T (=KCTC 3951T) and Paenibacillus alkaliterrae KSL-134T (=KCTC 3956T) with 96.3 and 96.5% gene sequence similarity, respectively. It contained meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The DNA G+C content was 52.9 mol%. The major isoprenoid quinone was MK-7. Anteiso-C15 : 0 and iso-C16 : 0 were the dominant cellular fatty acids. Based on phylogenetic, physiological and biochemical characteristics, strain N4T represents a novel species of the genus Paenibacillus , for which the name Paenibacillus vietnamensis sp. nov. is proposed. The type strain is N4T (=KCTC 33932T= VTCC 12236T).

Paenibacillus allorhizoplanae sp. nov. from the rhizoplane of a Zea mays root

A Gram-positive staining, aerobic, endospore-forming bacterial strain, isolated from the rhizosphere of Zea mays was studied for its detailed taxonomic allocation. Based on the 16S rRNA gene sequence similarity comparisons, strain JJ-42 ^T was shown to be a member of the genus Paenibacillus, most closely related to the type strain of Paenibacillus pectinilyticus (98.8%). The 16S rRNA gene sequence similarity to all other Paenibacillus species was below 98.5%. The pairwise average nucleotide identity (ANI) and digital DNA−DNA hybridization (dDDH) values of the JJ-42 ^T genome assembly against publicly available Paenibacillus type strain genomes were below 92% and 47%, respectively. The quinone system of strain JJ-42 ^T consisted exclusively of menaquinone MK-7. The polar lipid profile consisted of the major components diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three aminophospholipids (APL), and one unidentified lipid. The major fatty acids were iso- and anteiso-branched with the major compound anteiso C_15:0. Physiological and biochemical characteristics allowed a further phenotypic differentiation of strain JJ-42 ^T from the most closely related species. Thus, JJ-42 ^T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus allorhizoplanae sp. nov. is proposed, with JJ-42 ^T (= LMG 32089 ^T = CCM 9085 ^T = DSM 111786 ^T = CIP 111891 ^T) as the type strain.

Paenibacillus arenilitoris sp. nov., isolated from seashore sand and genome mining revealed the biosynthesis potential as antibiotic producer

Strain IB182493^T, a marine, aerobic, Gram-stain-negative and motile bacterium, was isolated from seashore sand of South China Sea. Cells grew optimally at 25-30 °C, pH 7.0-8.0 and with 2-4% NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that the strain formed a distinct lineage within the genus Paenibacillus, and was most closely related to Paenibacillus harenae DSM 16969 ^T (similarity 96.6%) and Paenibacillus alkaliterrae DSM 17040 ^T (similarity 96.1%). The chemotaxonomic characteristics of strain IB182493^T included MK-7 as the predominant isoprenoid quinone, anteiso-C_15:0 and iso-C_16:0 as the major cellular fatty acids and meso-diaminopimelic acid as the diagnostic diaminoacid in cell wall peptidoglycan. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and two unidentified phospholipids. The DNA G + C content of strain IB182493^T was 56.2 %. The values of whole genome average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) between the isolate and the closely related type strains were less than 84.7% and 23.6%, respectively. On the basis of phenotypic and chemotaxonomic properties, phylogenetic distinctiveness and genomic data, we named the strain as Paenibacillus arenilitoris sp. nov. and proposed that strain IB182493^T (= MCCC 1K04626^T = JCM 34215 ^T) in the genus Paenibacillus represents a novel species.