TY - JOUR

T1 - Proposal of Bacillus altaicus sp. nov. isolated from soil in the Altai region, Russia

AU - Шиков, Антон Евгеньевич

AU - Романенко, Мария Николаевна

AU - Шматов, Федор

AU - Белоусов, Михаил Владимирович

AU - Соловченко, Алексей

AU - Чивкунова, Ольга

AU - Савельев, Григорий

AU - Кузнецова, Ирина

AU - Карлов, Денис

AU - Нижников, Антон Александрович

AU - Антонец, Кирилл Сергеевич

PY - 2025/9/29

Y1 - 2025/9/29

N2 - The Altai Republic remains a geographic region with an uncovered microbial diversity hiding yet undescribed potential species. Here, we describe the strain al37.1T from the Altai soil. It showed genomic similarity with the Bacillus mycoides strain DSM 2048T. However, the in silico DNA–DNA hybridization (DDH) was 61.6%, which satisfies the accepted threshold for delineating species. The isolate formed circular, smooth colonies, in contrast to the rhizoidal morphology typical of B. mycoides. The strain showed optimal growth under the following conditions: pH 6.5, NaCl concentration 0.5% w/v, and +30 °C. The major fraction of fatty acids was composed of C16:0 (34.77%), C18:1 (15.20%), C14:0 (9.06%), and C18:0 (7.88%), which were sufficiently lower in DSM 2048T (C16:0–15.6%, C14:0–3.7%). In contrast to DSM 2048T, al37.1T utilized glycerol, D-mannose, and D-galactose, while being unable to assimilate D-sorbitol, D-melibiose, and D-raffinose. The strain contains biosynthetic gene clusters (BGCs) associated with the production of fengycin, bacillibactin, petrobactin, and paeninodin, as well as loci coding for insecticidal factors, such as Spp1Aa, chitinases, Bmp1, and InhA1/InhA2. The comparative analysis with the 300 closest genomes demonstrated that these BGCs and Spp1Aa could be considered core for the whole group. Most of the strains, coupled with al37.1T, contained full nheABC and hblABC operons orchestrating the synthesis of enteric toxins. We observed a cytotoxic effect (≈19 and 22% reduction in viability) of the strain on the PANC-1 cell line. Given the unique morphological features and genome-derived data, we propose a new species, B. altaicus, represented by the type strain al37.1T.

AB - The Altai Republic remains a geographic region with an uncovered microbial diversity hiding yet undescribed potential species. Here, we describe the strain al37.1T from the Altai soil. It showed genomic similarity with the Bacillus mycoides strain DSM 2048T. However, the in silico DNA–DNA hybridization (DDH) was 61.6%, which satisfies the accepted threshold for delineating species. The isolate formed circular, smooth colonies, in contrast to the rhizoidal morphology typical of B. mycoides. The strain showed optimal growth under the following conditions: pH 6.5, NaCl concentration 0.5% w/v, and +30 °C. The major fraction of fatty acids was composed of C16:0 (34.77%), C18:1 (15.20%), C14:0 (9.06%), and C18:0 (7.88%), which were sufficiently lower in DSM 2048T (C16:0–15.6%, C14:0–3.7%). In contrast to DSM 2048T, al37.1T utilized glycerol, D-mannose, and D-galactose, while being unable to assimilate D-sorbitol, D-melibiose, and D-raffinose. The strain contains biosynthetic gene clusters (BGCs) associated with the production of fengycin, bacillibactin, petrobactin, and paeninodin, as well as loci coding for insecticidal factors, such as Spp1Aa, chitinases, Bmp1, and InhA1/InhA2. The comparative analysis with the 300 closest genomes demonstrated that these BGCs and Spp1Aa could be considered core for the whole group. Most of the strains, coupled with al37.1T, contained full nheABC and hblABC operons orchestrating the synthesis of enteric toxins. We observed a cytotoxic effect (≈19 and 22% reduction in viability) of the strain on the PANC-1 cell line. Given the unique morphological features and genome-derived data, we propose a new species, B. altaicus, represented by the type strain al37.1T.

KW - Bacillus/genetics

KW - Fatty Acids/metabolism

KW - Genome, Bacterial

KW - Nucleic Acid Hybridization

KW - Phylogeny

KW - RNA, Ribosomal, 16S/genetics

KW - Russia

KW - Soil Microbiology

UR - https://www.mendeley.com/catalogue/d45bf034-e386-3a6e-a07d-5452b208fbb6/

U2 - 10.3390/ijms26199517

DO - 10.3390/ijms26199517

M3 - Article

C2 - 41096783

VL - 26

JO - International Journal of Molecular Sciences

JF - International Journal of Molecular Sciences

SN - 1422-0067

IS - 19

M1 - 9517

ER -