Methylobacterium nigriterrae sp. nov., isolated from black soil.

An aerobic, Gram-stain-negative, motile rod bacterium, designated as SYSU BS000021T, was isolated from a black soil sample in Harbin, Heilongjiang province, China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Methylobacterium, and showed the highest sequence similarity to Methylobacterium segetis KCTC 62267 T (98.51%) and Methylobacterium oxalidis DSM 24028 T (97.79%). Growth occurred at 20-37℃ (optimum, 28 °C), pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0% (w/v) NaCl. Polar lipids comprised of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified aminolipid and one unidentified polar lipid. The major cellular fatty acids (> 5%) were C18:0 and C18:1 ω7c and/or C18:1 ω6c. The predominant respiratory quinone was Q-10. The genomic G + C content was 68.36% based on the whole genome analysis. The average nucleotide identity (≤ 83.5%) and digital DNA-DNA hybridization (≤ 27.3%) values between strain SYSU BS000021T and other members of the genus Methylobacterium were all lower than the threshold values recommended for distinguishing novel prokaryotic species. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain SYSU BS000021T represents a novel species of the genus Methylobacterium, for which the name Methylobacterium nigriterrae sp. nov. is proposed. The type strain of the proposed novel species is SYSU BS000021T (= GDMCC 1.3814 T = KCTC 8051 T).

Two Novel Alkaliphilic Species Isolated from Saline-Alkali Soil in China: Halalkalibacter flavus sp. nov., and Halalkalibacter lacteus sp. nov.

The degradation of farmland in China underscores the need for developing and utilizing saline-alkali soil. Soil health relies on microbial activity, which aids in the restoration of the land's ecosystem, and hence it is important to understand microbial diversity. In the present study, two Gram-stain-positive strains HR 1-10T and J-A-003T were isolated from saline-alkali soil. Preliminary analysis suggested that these strains could be a novel species. Therefore, the taxonomic positions of these strains were evaluated using polyphasic analysis. Phylogenetic and 16S rRNA gene sequence analysis indicated that these strains should be assigned to the genus Halalkalibacter. Cell wall contained meso-2,6-diaminopimelic acid. The polar lipids present in both strains were diphosphatidyl-glycerol, phosphatidylglycerol, and an unidentified phospholipid. The major fatty acids (>10%) were anteiso-C15:0, C16:0 and iso-C15:0. Average nucleotide identity and digital DNA#x2013;DNA hybridization values were below the threshold values (95% and 70%, respectively) for species delineation. Based on the above results, the strains represent two novel species of the genus Halalkalibacter, for which the names Halalkalibacter flavus sp. nov., and Halalkalibacter lacteus sp. nov., are proposed. The type strains are HR 1-10T (=GDMCC 1.2946T = MCCC 1K08312T = JCM 36285T), and J-A-003T (=GDMCC 1.2949T = MCCC 1K08417T = JCM 36286T).

The shift of soil microbial community induced by cropping sequence affect soil properties and crop yield.

Rational cropping maintains high soil fertility and a healthy ecosystem. Soil microorganism is the controller of soil fertility. Meanwhile, soil microbial communities also respond to different cropping patterns. The mechanisms by which biotic and abiotic factors were affected by different cropping sequences remain unclear in the major grain-producing regions of northeastern China. To evaluate the effects of different cropping sequences under conventional fertilization practices on soil properties, microbial communities, and crop yield, six types of plant cropping systems were performed, including soybean monoculture, wheat-soybean rotation, wheat-maize-soybean rotation, soybean-maize-maize rotation, maize-soybean-soybean rotation and maize monoculture. Our results showed that compared with the single cropping system, soybean and maize crop rotation in different combinations or sequences can increase soil total organic carbon and nutrients, and promote soybean and maize yield, especially using soybean-maize-maize and maize-soybean-soybean planting system. The 16S rRNA and internal transcribed spacer (ITS) amplicon sequencing showed that different cropping systems had different effects on bacterial and fungal communities. The bacterial and fungal communities of soybean monoculture were less diverse when compared to the other crop rotation planting system. Among the different cropping sequences, the number of observed bacterial species was greater in soybean-maize-maize planting setup and fungal species in maize-soybean-soybean planting setup. Some dominant and functional bacterial and fungal taxa in the rotation soils were observed. Network-based analysis suggests that bacterial phyla Acidobacteria and Actinobacteria while fungal phylum Ascomycota showed a positive correlation with other microbial communities. The phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) result showed the presence of various metabolic pathways. Besides, the soybean-maize-maize significantly increased the proportion of some beneficial microorganisms in the soil and reduced the soil-borne animal and plant pathogens. These results warrant further investigation into the mechanisms driving responses of beneficial microbial communities and their capacity on improving soil fertility during legume cropping. The present study extends our understanding of how different crop rotations effect soil parameters, microbial diversity, and metabolic functions, and reveals the importance of crop rotation sequences. These findings could be used to guide decision-making from the microbial perspective for annual crop planting and soil management approaches.

Oceanobacillus saliphilus sp. nov., Isolated from Saline-Alkali Soil in Heilongjiang Province, China.

A novel bacterium, designated strain APA_H-1(4)T, was isolated from the saline-alkaline soil, Zhaodong, Heilongjiang Province, China. Phenotypic and chemotaxonomic analyses, and whole-genome sequencing were used to determine the taxonomic position of the strain. Phylogenetic analysis indicated that the isolate belongs to the genus Oceanobacillus, and showed the highest sequence similarity to O. damuensis KCTC 33146T (98.35%, similarity) and 'O. massiliensis' DSM 24644 (98.32%). The average nucleotide identity values between strain APA_H-1(4)T and other members of the genus Oceanobacillus were lower than 82% recommended for distinguishing novel prokaryotic species. The digital DNA-DNA hybridization values of strain APA_H-1(4)T with O. damuensis KCTC 33146T and 'O. massiliensis' DSM 24644 were 13.60 and 17.60%, respectively. Cells of strain APA_H-1(4)T were Gram-staining positive, motile, aerobic, spore-forming rods (0.5-0.7 × 1.8-2.6 µm) with flagella. The growth was found to occur optimally at 37 °C. The whole-cell hydrolysate contained meso-diaminopimelic acid as the diagnostic cell wall diamino acid. The main detected polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unidentified polar lipid. The predominant respiratory quinone was identified as menaquinone-7 (MK-7). The major cellular fatty acid (>10%) was anteiso-C15:0. The G + C content of the genomic DNA was determined to be 38.4% based on the draft genome sequence. Based on the comparative analysis of polyphasic taxonomic data, strain APA_H-1(4)T represents a novel species of the genus Oceanobacillus, for which the name Oceanobacillus saliphilus sp. nov. is proposed. The type strain is APA_H-1(4)T (=GDMCC 1.2239T = KCTC 43254T).

Alteribacter salitolerans sp. nov., isolated from a saline-alkaline soil.

A Gram-positive strain APA H-16(1)T was isolated from a saline-alkali soil sample collected from Heilongjiang Province, China. Cells were rod shaped, non-motile, endospore forming, and aerobic. Growth occurred at 10-45 °C (optimum, 35 °C), pH 7.0-10.5 (optimum, pH 9.5), and could tolerate NaCl up to 15.0% (w/v). Strain showed low 16S rRNA gene sequence similarities with Alteribacter natronophilus (97.8%), Alteribacter aurantiacus (97.7%), and Alteribacter populi (97.1%). The cell wall peptidoglycan was meso-diaminopimelic acid. The predominant menaquinone was MK-7. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified aminophospholipids, unidentified phospholipid, and unidentified lipid. The major fatty acids were anteiso-C15:0, and iso-C15:0. The genomic G + C content was 45.1%. The average nucleotide identity and digital DNA-DNA hybridization values between strain APA H-16(1)T and the most closely related species were below the cut-off level (95-96%; 70%) for species delineation. Based on phenotypic, phylogenetic, chemotaxonomic, and genome comparison, strain APA H-16(1)T represents a novel species of the genus Alteribacter, for which the name Alteribacter salitolerans sp. nov. is proposed. The type strain is APA H-16(1)T (= KCTC 43228T = CICC 25092T).