''Bacillus amyloliquefaciens'' is a species of

bacterium Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

in the genus ''

Bacillus ''Bacillus'' (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum ''Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacilli ...

'' that is the source of the

BamHI ''Bam''HI (pronounced "Bam H one") (from ''Bacillus amyloliquefaciens'') is a type II restriction endonuclease, having the capacity for recognizing short sequences (6 bp) of DNA and specifically cleaving them at a target site. This exhibit focus ...

restriction enzyme. It also synthesizes a natural

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

protein

barnase Barnase (a portmanteau of "BActerial" "RiboNucleASE") is a bacterial protein that consists of 110 amino acids and has ribonuclease activity. It is synthesized and secreted by the bacterium '' Bacillus amyloliquefaciens'', but is lethal to the cel ...

, a widely studied

ribonuclease Ribonuclease (commonly abbreviated RNase) is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within the ...

that forms a famously tight complex with its intracellular inhibitor

barstar Barstar is a small protein synthesized by the bacterium ''Bacillus amyloliquefaciens''. Its function is to inhibit the ribonuclease activity of its binding partner barnase Barnase (a portmanteau of "BActerial" "RiboNucleASE") is a bacterial pr ...

, and

plantazolicin Plantazolicin (PZN) is a natural antibiotic produced by the gram-positive soil bacterium ''Bacillus velezensis'' FZB42 (previously ''Bacillus amyloliquefaciens'' FZB42). PZN has specifically been identified as a selective bactericidal agent ac ...

, an antibiotic with selective activity against ''

Bacillus anthracis ''Bacillus anthracis'' is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent ( obligate) pathogen within the genus ''Bacillus''. Its infection is a ...

''. It is used in agriculture, aquaculture, and hydroponics to fight root pathogens such as ''

Ralstonia solanacearum ''Ralstonia solanacearum'' is an aerobic non-spore-forming, Gram-negative, plant pathogenic bacterium. ''R. solanacearum'' is soil-borne and motile with a polar flagellar tuft. It colonises the xylem, causing bacterial wilt in a very wide rang ...

,'' ''

Pythium ''Pythium'' is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but ''Pythium insidiosum'' is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequent ...

'', ''

Rhizoctonia solani ''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name ''Rhi ...

'', ''

Alternaria tenuissima ''Alternaria tenuissima'' is a saprophytic fungus and opportunistic plant pathogen. It is cosmopolitan in distribution, and can colonize a wide range of plant hosts. Colonies of ''A. tenuissima'' produce chains on agar growth media. The fungus o ...

'' and ''

Fusarium ''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...

'' as well improve root tolerance to salt stress. They are considered a growth-promoting

rhizobacteria Rhizobacteria are root-associated bacteria that can have a detrimental (parasitic varieties), neutral or beneficial effect on plant growth. The name comes from the Greek ''rhiza'', meaning root. The term usually refers to bacteria that form symbio ...

and have the ability to quickly colonize roots.

Discovery and name

''Bacillus amyloliquefaciens'' was discovered in soil 1943 by a Japanese scientist named Fukumoto, who gave the bacterium its name because it produced (''faciens'') a liquifying (''lique'')

amylase An amylase () is an enzyme that catalyses the hydrolysis of starch (Latin ') into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. Foods that contain large amounts of ...

(''amylo'').

Uses

Alpha amylase from ''B. amyloliquefaciens'' is often used in

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...

hydrolysis. It is also a source of

subtilisin Subtilisin is a protease (a protein-digesting enzyme) initially obtained from ''Bacillus subtilis''. Subtilisins belong to subtilases, a group of serine proteases that – like all serine proteases – initiate the nucleophilic attack on the p ...

, which catalyzes the breakdown of proteins in a similar way to

trypsin Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the dig ...

Agriculture

''Bacillus amyloliquefaciens'' is considered a root-colonizing biocontrol bacterium, and is used to fight some plant root pathogens in agriculture, aquaculture, and hydroponics. It has been shown to provide benefits to plants in both soil and hydroponic applications. It takes action against bacterial and fungi pathogens, and may prevent infection though

competitive exclusion In ecology, the competitive exclusion principle, sometimes referred to as Gause's law, is a proposition that two species which compete for the same limited resource cannot coexist at constant population values. When one species has even the sligh ...

or out-competing the unwanted pathogen. It has been shown to be effective against several root pathogens that hurt agricultural yields in soil and hydroponics, such as ''Ralstonia solanacearum'' in tomatoes, ''Rhizoctonia solani'' in lettuce, ''Pythium'' in tomatoes, ''Alternaria tenuissima'' in English ivy and ''Fusarium'' in bananas and cucumbers. It also appears to improve root tolerance against abiotic stress, allowing plants such as maize to tolerate high salt concentrations in hydroponic applications, while also reducing salt concentrations in the plant tissue.

Status as a species

Between the 1940s and the 1980s, bacteriologists debated as to whether or not ''B. amyloliquefaciens'' was a separate species or a subspecies of ''

Bacillus subtilis ''Bacillus subtilis'', known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus ''Bacillu ...

''. The matter was settled in 1987; it was established to be a separate species. In the

American Type Culture Collection ATCC or the American Type Culture Collection is a nonprofit organization which collects, stores, and distributes standard reference microorganisms, cell lines and other materials for research and development. Established in 1925 to serve as a natio ...

, the number for ''B. amyloliquefaciens'' is 23350. ''Bacillus amyloliquefaciens'' FZB42, the producer of the ultranarrow-spectrum antibiotic

, was reclassified in 2015 as ''B. velezensis'' NRRL B-41580T (along with ''B. methylotrophicus'' KACC 13015 T and ''B. oryzicola'' KACC 18228) based on phenotype and genotype coherence.

References

External links

Type strain of ''Bacillus amyloliquefaciens'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q4354408 amyloliquefaciens Bacteria described in 1987 Biological pest control