Plant antibiotics produced through tissue culture

• Antibiotics:  

• Antibiotics are substances produced by certain microorganisms that suppress the growth of other microorganisms and eventually destroy them.

Antimicrobials in Plant Tissue Culture

Antibiotics (Antimicrobials)

• Bacteristatic–Inhibit bacterial growth; bacteria viable but “dormant”. Growth resumes in antibiotic-free medium.

• Bactericidal –Lethal to bacteria; no subsequent growth in antibiotic-free medium

• Antifungal (Antimycotics) –Fungistatic& Fungicidal• Broad-spectrum Antimicrobials –Inhibit or eliminate

bacteria and fungi.• Antiviral –Inactivate virus

Ideally, Antibiotics in Plant Tissue Culture are:

• Stable Broad spectrum of activity• Unaffected by media pH or components Low chance of

bacterial resistance• Inexpensive Lethal to microbe• Minimal side effects

• (no phytotoxicity) Usable in combinations

Effect on Multiplication

• Grading antibiotics based on their inhibitory effect on plant growth (reduced multiplication rate in vitro):

• Most Inhibitory• Streptomycin Polymyxin-B ⇒ ⇒• Rifampicin Carbenicillin⇒

– Least Inhibitory

Do I Have to Add Antibiotics to the Medium?

– Not necessarily…• Stock Plant Treatment–Reduced phytotoxicity

– •Heveashoots-tips inhibited growth w/ antibiotics in ⇒medium.

– •No inhibition if stock plant sprayed every 2 days for 2 weeks before culture.

– •Contamination controlled • Other studies have shown reduced bacterial

growth in shoot-tips & buds w/ regular antibiotic treatments to stock pants.

Bacteristatic Bactericidal

Reversible inhibition of bacterial growth.

Lethal to Bacteria.

May have bactericidal activity at high concentrations.

Bacteristaticat low concentrations.

Includes:

Choramphenicols

Tetracyclines

Macrolides (Erythromycin)

Includes:

Aminoglycosides

Cephalosporins

Penicillins

Polymyxins(Polymyxin-B)

Rifamycins(Rifampicin)

Antifungals(Antimycotics)

– Amphotericin B• Cycloheximide

• Nystatin

• Griseofulvin– Petachloronitrobenzene(PCNB)

• Thiabendazole

Wide-Spectrum Antimicrobials

• PPM™(Plant Preservative Mixture)

• 8-Hydroxyquinoline

thiostrepton