2023,
Journal of Bacteriology.
DOI:
10.1128/jb.00165-23
Three genes controlling streptomycin susceptibility in Agrobacterium fabrum
Robyn E. Howarth, Curtis M. Pattillo, Joel S. Griffitts, Diana G. Calvopina-Chavez
Abstract:
ABSTRACT
Streptomycin (Sm) is a commonly used antibiotic for its efficacy against diverse bacteria. The plant pathogen
Agrobacterium fabrum
is a model for studying pathogenesis and interkingdom gene transfer. Streptomycin-resistant variants of
A. fabrum
are commonly employed in genetic analyses, yet mechanisms of resistance and susceptibility to streptomycin in this organism have not previously been investigated. We observe that resistance to a high concentration of streptomycin arises at high frequency in
A. fabrum
, and we attribute this trait to the presence of a chromosomal gene (
strB
) encoding a putative aminoglycoside phosphotransferase. We show how
strB
, along with
rpsL
(encoding ribosomal protein S12) and
rsmG
(encoding a 16S rRNA methyltransferase), modulates streptomycin sensitivity in
A. fabrum
.
IMPORTANCE
The plant pathogen
Agrobacterium fabrum
is a widely used model bacterium for studying biofilms, bacterial motility, pathogenesis, and gene transfer from bacteria to plants. Streptomycin (Sm) is an aminoglycoside antibiotic known for its broad efficacy against gram-negative bacteria.
A. fabrum
exhibits endogenous resistance to somewhat high levels of streptomycin, but the mechanism underlying this resistance has not been elucidated. Here, we demonstrate that this resistance is caused by a chromosomally encoded streptomycin-inactivating enzyme, StrB, that has not been previously characterized in
A. fabrum
. Furthermore, we show how the genes
rsmG
,
rpsL
, and
strB
jointly modulate streptomycin susceptibility in
A. fabrum
.
Streptomycin (Sm) is a commonly used antibiotic for its efficacy against diverse bacteria. The plant pathogen
is a model for studying pathogenesis and interkingdom gene transfer. Streptomycin-resistant variants of
are commonly employed in genetic analyses, yet mechanisms of resistance and susceptibility to streptomycin in this organism have not previously been investigated. We observe that resistance to a high concentration of streptomycin arises at high frequency in
, and we attribute this trait to the presence of a chromosomal gene (
) encoding a putative aminoglycoside phosphotransferase. We show how
, along with
(encoding ribosomal protein S12) and
(encoding a 16S rRNA methyltransferase), modulates streptomycin sensitivity in
.
The plant pathogen
is a widely used model bacterium for studying biofilms, bacterial motility, pathogenesis, and gene transfer from bacteria to plants. Streptomycin (Sm) is an aminoglycoside antibiotic known for its broad efficacy against gram-negative bacteria.
exhibits endogenous resistance to somewhat high levels of streptomycin, but the mechanism underlying this resistance has not been elucidated. Here, we demonstrate that this resistance is caused by a chromosomally encoded streptomycin-inactivating enzyme, StrB, that has not been previously characterized in
. Furthermore, we show how the genes
,
, and
jointly modulate streptomycin susceptibility in
.
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2023-10-30 16:06:00
钟鸣:
#paper doi: 10.1128/jb.00165-23 Three genes controlling streptomycin susceptibility in Agrobacterium fabrum 链霉素是一种氨基糖苷类抗生素，通过干扰16S rRNA的正常工作阻碍细菌复制，实现抗菌效果。农杆菌的链霉素抗性通常由rpsL、rsmG（也称为gidB）和rrs突变引起。本课题中，作者使用链霉菌做连续培养筛选和分析，获取了在低浓度和高浓度抗生素下筛选到的耐药菌准，由于传代筛选过程中未引入外源基因，表明内源性基因的突变调控了耐药性。由于低浓度下的突变体的耐药性高于高浓度下的突变体，因此作者分别对这两批突变体进行了测序。作者首先发现高浓度突变株的rpsL发生了突变而低浓度的没有，对突变的rpsL等位基因进行转移实现，验证了该等位基因能赋予野生型耐药性。对6株低浓度突变体的测序发现，都发生了导致rsmG功能丧失的突变，随后的敲除和回补实证实了该基因突变对链霉素抗性的影响。