Title |
Comparative genomics of Lactobacillus species as bee symbionts and description of Lactobacillus bombintestini sp. nov., isolated from the gut of Bombus ignitus |
Author |
Jun Heo, Soo-Jin Kim, Jeong-Seon Kim, Seung-Beom Hong, and Soon-Wo Kwon* |
Address |
Agricultural Microbiology Division, National Institute of Agricultural Sciences, Rural Development Administration, Jeollabuk-do 55365, Republic of Korea |
Bibliography |
Journal of Microbiology, 58(6),445–455, 2020,
|
DOI |
10.1007/s12275-020-9596-3
|
Key Words |
Lactobacillus bombintestini, Bombus ignitus, bee
gut, mutY |
Abstract |
The Lactobacillus genus is widely used for fermentation of
plant materials and dairy products. These species are typically
found in highly specialized environments, with the bee gut
serving as one of the niche locations in which Lactobacillus
is detected. Lactobacillus species isolated from the bee gut and
bee-related habitats were phylogenetically classified into three
distinct groups, Lactobacillus kunkeei, Firm-4, and Firm-5.
The L. kunkeei group was clearly differentiated from other
members of the Lactobacillus buchneri group isolated from
non-bee habitats. In comparison with non-bee members of the
L. buchneri group, three bee-symbiotic Lactobacillus groups
had a small-sized genome with low G + C content and showed
a sharp reduction in the number of genes involved in energy
production, carbohydrate transport and metabolism, and
amino acid transport and metabolism. In addition, all three
groups lacked the mutY gene, which encodes A/G-specific
adenine glycosylase. The phylogenetic dendrogram based on
the presence or absence of 1,199 functional genes indicated
that these bee-symbiotic groups experienced convergent evolution.
The occurrence of convergent evolution is thought to
stem from the three bee-symbiotic groups sharing a similar
habitat, i.e., the bee gut. The causative factor underlying genomic
reduction was postulated to be mutY, which was absent
in all three groups. Here, a novel strain, BHWM-4T, isolated
from the gut of Bombus ignites was studied using polyphasic
taxonomy and classified as a new member of the L.
kunkeei group. The strain was Gram-positive, facultative anaerobic,
and rod-shaped. The 16S ribosomal RNA gene sequence
and genome analysis revealed that strain BHWM-4T was
clustered into the L. kunkeei group, forming a compact cluster
with L. kunkeei and Lactobacillus apinorum. Biochemical,
chemotaxonomic, and genotypic data of strain BHWM-4T
supports the proposal of a novel species, Lactobacillus bombintestini
sp. nov., whose type strain is BHWM-4T (= KACC
19317T = NBRC 113067T). |