horC confers beer-spoilage ability on hop-sensitive Lactobacillus brevis ABBC45cc.
OBJECTIVE
To determine whether horC confers beer-spoilage ability and to evaluate the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of lactic acid bacteria (LAB).


RESULTS
Hop-sensitive Lactobacillus brevis ABBC45cc was transformed with an expression plasmid, pHYchorBC, containing putative multidrug resistance gene horC and its putative regulator horB, and the transformant was designated as ABBC45cc/pHYchorBC. As a control, ABBC45cc was transformed with pHYchorB that contains horB, and the transformed strain was designated as ABBC45cc/pHYchorB. As a result of beer-spoilage assay of these transformants, ABBC45cc/pHYchorBC exhibited beer-spoilage ability, whereas ABBC45cc/pHYchorB did not. Furthermore ABBC45cc/pHYchorBC showed higher hop resistance than ABBC45cc/pHYchorB, accounting for the differences in beer-spoilage ability observed between the two transformants. ABBC45cc/pHYchorBC also exhibited higher resistance to various structurally unrelated drugs, compared with ABBC45cc/pHYchorB.


CONCLUSIONS
horC was shown to confer hop resistance and beer-spoilage ability on ABBC45cc by presumably encoding a multidrug transporter.


CONCLUSIONS
The finding that horC plays an important role in hop resistance and beer-spoilage ability supports the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of LAB.
Iijima
K
K
Analytical Technology Laboratory, Asahi Breweries, Ltd, Ibaraki, Japan. kazumaru.iijima@asahibeer.co.jp
Suzuki
K
K
Ozaki
K
K
Yamashita
H
H
D001426:Bacterial Proteins / Q000235:genetics*; D001515:Beer; D005506:Food Contamination; D005798:Genes, Bacterial; D005819:Genetic Markers; D027582:Humulus / Q000382:microbiology*; D007218:Industrial Microbiology; D052196:Levilactobacillus brevis / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D014170:Transformation, Genetic; D019076:Transgenes
D001426:Bacterial Proteins; D005819:Genetic Markers; C110353:hor protein, bacteria